教你用Java实现一个简单的代码生成器-APISpace

教你用Java实现一个简单的代码生成器

前言

逆向工程从数据库表直接生成代码，是日常开发中常用的敏捷开发手段，常见的例如：mybatis-plus的代码生成器等

为什么要自己写代码生成器呢？MP的生成器不香吗？香！

但是自己写的工具用起来最顺手，可以随意扩展，想怎么玩就怎么玩，只要自己有想法，玩出花来都没问题，当然了，能力有限，现在还只能实现简单版本，更多骚操作自己发挥！

思路：

1、建立jdbc连接，执行查询sql，获取表结构信息。

2、在指定的路径上创建文件。

3、按照我们的布局排版要求，根据表结构信息拼接文件的内容。

4、将字符输出到文件中。

以上即可完成一个文件的自动生成

编码

通用部分

几个内部工具类

file工具类：创建、读取文件

字符串工具类：驼峰标识、下划线互转，首字母大写，数据库字段类型转java类型等

jdbc连接：连接数据库

表注释、表结构信息实体类、执行sql获取表结构信息的方法

表结构信息

private String columnName;//字段名

private String dataType;//字段类型

private String columnComment;//字段注释

private String columnKey;//主键

private String extra;//主键类型

mysql查询表注释、表字段信息使用的是

表字段信息

SELECT

column_name,

data_type,

column_comment,

column_key,

extra

FROM

information_schema.COLUMNS

WHERE

table_schema = (

SELECT DATABASE

())

AND table_name =?

表注释

SELECT

table_comment

FROM

information_schema.TABLES

WHERE

table_schema = (

SELECT DATABASE

())

AND table_name =?

需要支持其他数据库类型的，自己调整就好了，例如oracle获取表注释、表结构sql如下：

-- 表、表注释

SELECT

t.table_name,

t1.comments

FROM

user_tables t

JOIN user_tab_comments t1 ON t.table_name = t1.table_name;

-- 表字段、字段注释

SELECT

t.table_name,

c.column_name,

c.data_type,

cc.comments

FROM

USER_TAB_COLUMNS c

JOIN user_tables t ON c.table_name = t.table_name

JOIN user_col_comments cc ON cc.table_name = t.table_name

WHERE

cc.column_name = c.column_name;

另外，数据连接、基础路径的配置也是一样

/**

* 数据连接相关，需要手动设置

private static final String URL = "jdbc:mysql://localhost:3306/test?serverTimezone=GMT%2B8&characterEncoding=utf-8";

private static final String USERNAME = "root";

private static final String PASSWORD = "123456";

private static final String DRIVER_CLASSNAME = "com.mysql.cj.jdbc.Driver";

/**

* 基础路径，需要手动设置

private String basePackage = "cn\\huanzi\\qch\\baseadmin\\";//根包位置

private String filePackage = basePackage + "sys\\";//文件所在包位置

2.0版本多一个模板文件路径

private String tlfPath = System.getProperty("user.dir") + "\\src\\main\\resources\\tlf\\";//模板文件位置

main函数也一样，调用构造参数，传入表名，调用入口函数

public static void main(String[] args) {

// String[] tables = {"sys_user","sys_menu","sys_authority","sys_user_menu","sys_user_authority","sys_shortcut_menu","sys_setting"};

String[] tables = {"tb_user"};

for (String table : tables) {

String msg = new AutoGenerator(table).create();

System.out.println(msg);

}

V1.0版本

AutoGenerator，1.0版本采用原始的在代码拼接字符串，然后创建文件将字符串输出的方法，比较原始但个人觉得可玩性较高

几个创建方法，就拿实体类来举例

/**

* 创建pojo实体类

private void createPojo(List tableInfos) {

//创建文件

File file = FileUtil.createFile(filePath + "pojo\\" + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + ".java");

//拼接文件内容

StringBuffer stringBuffer = new StringBuffer();

stringBuffer.append(

"package " + filePackage.replaceAll("\\\\", ".") + "pojo;\n" +

"\n" +

"import lombok.Data;\n" +

"import javax.persistence.*;\n" +

"import java.io.Serializable;\n" +

"import java.util.Date;\n" +

"\n" +

"@Entity\n" +

"@Table(name = \"" + tableName + "\")\n" +

"@Data\n" +

"public class " + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + " implements Serializable {\n"

);

//遍历设置属性

for (TableInfo tableInfo : tableInfos) {

//主键

if ("PRI".equals(tableInfo.getColumnKey())) {

stringBuffer.append(" @Id\n");

}

//自增

if ("auto_increment".equals(tableInfo.getExtra())) {

stringBuffer.append(" @GeneratedValue(strategy= GenerationType.IDENTITY)\n");

}

stringBuffer.append(" private ").append(StringUtil.typeMapping(tableInfo.getDataType())).append(" ").append(StringUtil.camelCaseName(tableInfo.getColumnName())).append(";//").append(tableInfo.getColumnComment()).append("\n\n");

}

stringBuffer.append("}");

//写入文件内容

FileUtil.fileWriter(file, stringBuffer);

}

其他的也一样，无非就：创建文件、拼接文件内容、输出文件内容

入口函数，供main函数直接调用

/**

* 快速创建，供外部调用，调用之前先设置一下项目的基础路径

private String create() {

System.out.println("生成路径位置：" + filePath);

//获取表信息

List tableInfo = getTableInfo();

//开始生成代码

createPojo(tableInfo);

createVo(tableInfo);

createRepository(tableInfo);

createService(tableInfo);

createController(tableInfo);

return tableName + " 后台代码生成完毕！";

}

V2.0版本

AutoGeneratorPlus，2.0版本升级了，设置了模板文件、文件内容的字符串从模板读取，再根据关键字替换参数，最后再输出到创建的文件中，这个版本就比较好理解，大部分的代码生成器也都这样干

需要先定义模板文件（文件名后缀无所谓，自己随便定义），拿entity来举例

package cn.huanzi.qch.baseadmin.sys.${entityToLowerCase}.pojo;

import lombok.Data;

import javax.persistence.*;

import java.io.Serializable;

import java.util.Date;

/**

* ${tableComment} 实体类

* ${author}

* ${date}

@Entity

@Table(name = "${tableName}")

@Data

public class ${entity} implements Serializable {

#for

#ifPri

#ifAutoIncrement

private ${tableInfo.dataType} ${tableInfo.columnName};//${tableInfo.columnComment}

#end

}

${}，用于取参数，替换成我们的值

#for、#if，循环遍历表字段以及判断是否为主键、是否主键自增

各种关键字随便定义，我们在读取模板文件处理时能对上就行

文件内容处理

/**

* 读取模板，设置内容，生成文件

* @param templatePath 模板文件路径

* @param outputFile 文件生成路径

* @param tableInfos 表字段信息

* @param customParameter 自定义参数

private void writer(String templatePath, String outputFile,List tableInfos,Map customParameter){

//主键

TableInfo prikey = new TableInfo();

//for循环标识

boolean forFlag = false;

StringBuilder forContent = new StringBuilder();

//驼峰标识映射后的表名

String replacement = StringUtil.captureName(StringUtil.camelCaseName(tableName));

//遍历属性

for (TableInfo tableInfo : tableInfos) {

//主键

if ("PRI".equals(tableInfo.getColumnKey())) {

prikey = tableInfo;

break;

}

try(FileReader fileReader = new FileReader(templatePath);

BufferedReader reader = new BufferedReader(fileReader)) {

//生成文件

File file = FileUtil.createFile(outputFile);

StringBuffer stringBuffer = new StringBuffer();

//读取模板文件，拼接文件内容

Object[] lines = reader.lines().toArray();

for (Object o : lines) {

String line = String.valueOf(o);

/* 设置值 */

//${tableName} 表名称，例如：tb_user

if(line.contains("${tableName}")){

line = line.replaceAll("\\$\\{tableName}", tableName);

}

//${tableComment} 表注释，例如：tb_user

if(line.contains("${tableComment}")){

line = line.replaceAll("\\$\\{tableComment}", tableComment);

}

//${entity} 实体类名称，例如：TbUser

if(line.contains("${entity}")){

line = line.replaceAll("\\$\\{entity}", replacement);

}

//${entityFirstToLowerCase} 实体类名称首字母小写，例如：tbUser

if(line.contains("${entityFirstToLowerCase}")){

line = line.replaceAll("\\$\\{entityFirstToLowerCase}", StringUtil.camelCaseName(tableName));

}

//${entityToLowerCase} 实体类名称全小写，例如：tbuser

if(line.contains("${entityToLowerCase}")){

line = line.replaceAll("\\$\\{entityToLowerCase}", replacement.toLowerCase());

}

//${priDataType} 实体类主键类型，例如：String

if(line.contains("${priDataType}")){

line = line.replaceAll("\\$\\{priDataType}", StringUtil.typeMapping(prikey.getDataType()));

}

//处理自定义参数

line = customParameter(line,customParameter);

//先取得循环体的内容

if(forFlag){

forContent.append(line).append("\n");

}

//是否为for循环遍历表字段

if(line.contains("#for")){

forFlag = true;

}

if(line.contains("#end")){

forFlag = false;

line = line.replaceAll("#end", "");

}

//遍历循环体的内容，并设置值

if(!forFlag && forContent.length() > 0){

//遍历表字段

for (TableInfo tableInfo : tableInfos) {

String tableColumns = forContent.toString()

//表字段信息：类型、名称、注释

.replaceAll("\\$\\{tableInfo.dataType}", StringUtil.typeMapping(tableInfo.getDataType()))

.replaceAll("\\$\\{tableInfo.columnName}", StringUtil.camelCaseName(tableInfo.getColumnName()))

.replaceAll("\\$\\{tableInfo.columnComment}", tableInfo.getColumnComment());

//清除多余#end，以及换行符

tableColumns = tableColumns.replaceAll("#end", "").replaceAll("\n", "");

//设置是否主键、是否自增

String pri = "",autoIncrement="";

//主键

if ("PRI".equals(tableInfo.getColumnKey())) {

pri = " @Id\n";

//自增idSbAaNTddMC

if ("auto_increment".equals(tableInfo.getExtra())){

http:// autoIncrement = "@GeneratedValue(strategy= GenerationType.IDENTITY)\n";

}

tableColumns = tableColumns

.replaceAll("#ifPri", pri)

.replaceAll("#ifAutoIncrement", autoIncrement);

//处理自定义参数

tableColumns = customParameter(tableColumns,customParameter);

//前补tab，后补换行符

stringBuffer.append(" ").append(tableColumns.trim()).append("\n\n");

}

//置空

forContent.setLength(0);

}

if(!forFlag){

stringBuffer.append(line).append("\n");

}

//写入数据到到文件中

FileUtil.fileWriter(file, stringBuffer);

}catch (Exception e){

e.printStackTrace();

}

内置了几个重要参数

${tableName} 表名称，例如：tb_user

${tableComment} 表注释，例如：tb_user

${entity} 实体类名称，例如：TbUser

${entityFirstToLowerCase} 实体类名称首字母小写，例如：tbUser

${entityToLowerCase} 实体类名称全小写，例如：tbuser

${priDataType} 实体类主键类型，例如：String

还有三个表字段信息：类型、名称、注释

${tableInfo.dataType}

${tableInfo.columnName}

${tableInfo.columnComment}

支持自定义参数Map customParameter，例如模板文件中的注释：

/**

* ${author}

* ${date}

入口函数

/**

* 快速创建，供外部调用，调用之前先设置一下项目的基础路径

private String create() {

System.out.println("生成路径位置：" + filePath);

//获取表信息

List tableInfo = getTableInfo();

//驼峰标识映射后的表名

String captureName = StringUtil.captureName(StringUtil.camelCaseName(tableName));

//自定义参数

HashMap customParameter = new HashMap<>();

customParameter.put("date","生成日期："+new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date()));

//读取模板、生成代码

writer(tlfPath+"controller.tlf",

filePath + "controller\\" + captureName + "Controller.java",

tableInfo,customParameter);

writer(tlfPath+"entity.tlf",

filePath + "pojo\\" + captureName + ".java",

tableInfo,customParameter);

writer(tlfPath+"entityvo.tlf",

filePath + "vo\\" + captureName + "Vo.java",

tableInfo,customParameter);

writer(tlfPath+"repository.tlf",

filePath + "repository\\" + captureName + "Repository.java",

tableInfo,customParameter);

writer(tlfPath+"service.tlf",

filePath + "service\\" + captureName + "Service.java",

tableInfo,customParameter);

writer(tlfPath+"serviceimpl.tlf",

filePath + "service\\" + captureName + "ServiceImpl.java",

tableInfo,customParameter);

return tableName + " 后台代码生成完毕！";

}

比较复杂的就是#for、#if的处理，我这里只是简单实现，不过也完全够我们用了

效果

V1.0版本

V2.0版本

后记

大部分项目的代码都是可以复用的，特别是像我们这种封装了一套通用代码，单表直接继承实现CRUD、分页等功能，每个模块高度相似的代码，代码生成器就成了敏捷开发中重要的一步，直接根据数据库表生成我们想要的代码，省去了一步步创建文件、复制粘贴文件内容的繁琐步骤，实现快速开发！

自己写的代码生成器，扩展性更强，满足每个业务模块的代码要求不成问题

开源

在这里贴出完整代码，全都在一个类里面，并且没有其他依赖包，很纯！

v1.0AutoGenerator

package cn.huanzi.qch.baseadmin.autogenerator;

import java.io.File;

import java.io.FileWriter;

import java.io.PrintWriter;

import java.sql.*;

import java.util.ArrayList;

import java.util.List;

/**

* 代码生成工具 V1.0

public class AutoGenerator {

/**

* 程序自动设置

private String tableName;//表名

private String tableComment;//表注释

private String filePath;//最终文件生成位置

/**

* 数据连接相关，需要手动设置

private static final String URL = "jdbc:mysql://localhost:3306/test?serverTimezone=GMT%2B8&characterEncoding=utf-8";

private static final String USERNAME = "root";

private static final String PASSWORD = "123456";

private static final String DRIVER_CLASSNAME = "com.mysql.cj.jdbc.Driver";

/**

* 基础路径，需要手动设置

private String basePackage = "cn\\huanzi\\qch\\baseadmin\\";//根包位置

private String filePackage = basePackage + "sys\\";//文件所在包位置

/**

* 构造参数，设置表名

private AutoGenerator(String tableName) {

//设置表名

this.tableName = tableName;

//文件所在包位置

filePackage = filePackage + StringUtil.camelCaseName(tableName).toLowerCase() + "\\";

//拼接完整最终位置 System.getProperty("user.dir") 获取的是项目所在路径，如果我们是子项目，则需要添加一层路径

filePath = System.getProperty("user.dir") + "\\src\\main\\java\\" + filePackage;

}

/**

* 创建pojo实体类

private void createPojo(List tableInfos) {

//创建文件

File file = FileUtil.createFile(filePath + "pojo\\" + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + ".java");

//拼接文件内容

StringBuffer stringBuffer = new StringBuffer();

stringBuffer.append(

"package " + filePackage.replaceAll("\\\\", ".") + "pojo;\n" +

"\n" +

"import lombok.Data;\n" +

"import javax.persistence.*;\n" +

"import java.io.Serializable;\n" +

"import java.util.Date;\n" +

"\n" +

"@Entity\n" +

"@Table(name = \"" + tableName + "\")\n" +

"@Data\n" +

"public class " + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + " implements Serializable {\n"

);

//遍历设置属性

for (TableInfo tableInfo : tableInfos) {

//主键

if ("PRI".equals(tableInfo.getColumnKey())) {

stringBuffer.append(" @Id\n");

}

//自增

if ("auto_increment".equals(tableInfo.getExtra())) {

stringBuffer.append(" @GeneratedValue(strategy= GenerationType.IDENTITY)\n");

}

stringBuffer.append("}");

//写入文件内容

FileUtil.fileWriter(file, stringBuffer);

}

/**

* 创建vo类

private void createVo(List tableInfos) {

File file = FileUtil.createFile(filePath + "vo\\" + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "Vo.java");

StringBuffer stringBuffer = new StringBuffer();

stringBuffer.append(

"package " + filePackage.replaceAll("\\\\", ".") + "vo;\n" +

"\n" +

"import "+ basePackage.replaceAll("\\\\", ".") +" common.pojo.PageCondition;"+

"import lombok.Data;\n" +

"import java.io.Serializable;\n" +

"import java.util.Date;\n" +

"\n" +

"@Data\n" +

"public class " + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "Vo extends PageCondition implements Serializable {\n"

);

//遍历设置属性

for (TableInfo tableInfo : tableInfos) {

}

stringBuffer.append("}");

FileUtil.fileWriter(file, stringBuffer);

}

/**

* 创建repository类

private void createRepository(List tableInfos) {

File file = FileUtil.createFile(filePath + "repository\\" + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "Repository.java");

StringBuffer stringBuffer = new StringBuffer();

String t = "String";

//遍历属性

for (TableInfo tableInfo : tableInfos) {

//主键

if ("PRI".equals(tableInfo.getColumnKey())) {

t = StringUtil.typeMapping(tableInfo.getDataType());

}

stringBuffer.append(

"package " + filePackage.replaceAll("\\\\", ".") + "repository;\n" +

"\n" +

"import " + basePackage.replaceAll("\\\\", ".") + "common.repository.*;\n" +

"import " + filePackage.replaceAll("\\\\", ".") + "pojo." + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + ";\n" +

"import org.springframework.stereotype.Repository;\n" +

"\n" +

"@Repository\n" +

"public interface " + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "Repository extends CommonRepository<" + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + ", " + t + "> {"

);

stringBuffer.append("\n");

stringBuffer.append("}");

FileUtil.fileWriter(file, stringBuffer);

}

/**

* 创建service类

private void createService(List tableInfos) {

File file = FileUtil.createFile(filePath + "service\\" + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "Service.java");

StringBuffer stringBuffer = new StringBuffer();

String t = "String";

//遍历属性

for (TableInfo tableInfo : tableInfos) {

//主键

if ("PRI".equals(tableInfo.getColumnKey())) {

t = StringUtil.typeMapping(tableInfo.getDataType());

}

stringBuffer.append(

"package " + filePackage.replaceAll("\\\\", ".") + "service;\n" +

"\n" +

"import " + basePackage.replaceAll("\\\\", ".") + "common.service.*;\n" +

"import " + filePackage.replaceAll("\\\\", ".") + "pojo." + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + ";\n" +

"import " + filePackage.replaceAll("\\\\", ".") + "vo." + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "Vo;\n" +

"\n" +

"public interface " + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "Service extends CommonService<" + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "Vo, " + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + ", " + t + "> {"

);

stringBuffer.append("\n");

stringBuffer.append("}");

FileUtil.fileWriter(file, stringBuffer);

//Impl

File file1 = FileUtil.createFile(filePath + "service\\" + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "ServiceImpl.java");

StringBuffer stringBuffer1 = new StringBuffer();

stringBuffer1.append(

"package " + filePackage.replaceAll("\\\\", ".") + "service;\n" +

"\n" +

"import " + basePackage.replaceAll("\\\\", ".") + "common.service.*;\n" +

"import " + filePackage.replaceAll("\\\\", ".") + "pojo." + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + ";\n" +

"import " + filePackage.replaceAll("\\\\", ".") + "vo." + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "Vo;\n" +

"import " + filePackage.replaceAll("\\\\", ".") + "repository." + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "Repository;\n" +

"import org.springframework.beans.factory.annotation.Autowired;\n" +

"import org.springframework.stereotype.Service;\n" +

"import org.springframework.transaction.annotation.Transactional;\n" +

"import javax.persistence.EntityManager;\n" +

"import javax.persistence.PersistenceContext;\n" +

"\n" +

"@Service\n" +

"@Transactional\n" +

"public class " + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "ServiceImpl extends CommonServiceImpl<" + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "Vo, " + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + ", " + t + "> implements " + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "Service{"

);

stringBuffer1.append("\n\n");

stringBuffer1.append(

" @PersistenceContext\n" +

" private EntityManager em;\n");

stringBuffer1.append("" +

" @Autowired\n" +

" private " + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "Repository " + StringUtil.camelCaseName(tableName) + "Repository;\n");

stringBuffer1.append("}");

FileUtil.fileWriter(file1, stringBuffer1);

}

/**

* 创建controller类

private void createController(List tableInfos) {

File file = FileUtil.createFile(filePath + "controller\\" + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "Controller.java");

StringBuffer stringBuffer = new StringBuffer();

String t = "String";

//遍历属性

for (TableInfo tableInfo : tableInfos) {

//主键

if ("PRI".equals(tableInfo.getColumnKey())) {

t = StringUtil.typeMapping(tableInfo.getDataType());

}

stringBuffer.append(

"package " + filePackage.replaceAll("\\\\", ".") + "controller;\n" +

"\n" +

"import " + basePackage.replaceAll("\\\\", ".") + "common.controller.*;\n" +

"import " + filePackage.replaceAll("\\\\", ".") + "pojo." + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + ";\n" +

"import " + filePackage.replaceAll("\\\\", ".") + "vo." + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "Vo;\n" +

"import " + filhttp://ePackage.replaceAll("\\\\", ".") + "service." + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "Service;\n" +

"import org.springframework.beans.factory.annotation.Autowired;\n" +

"import org.springframework.web.bind.annotation.*;\n" +

"\n" +

"@RestController\n" +

"@RequestMapping(\"/sys/" + StringUtil.camelCaseName(tableName) + "/\")\n" +

"public class " + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "Controller extends CommonController<" + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "Vo, " + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + ", " + t + "> {"

);

stringBuffer.append("\n");

stringBuffer.append("" +

" @Autowired\n" +

" private " + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "Service " + StringUtil.camelCaseName(tableName) + "Service;\n");

stringBuffer.append("}");

FileUtil.fileWriter(file, stringBuffer);

}

/**

* file工具类

private static class FileUtil {

/**

* 创建文件

* @param pathNameAndFileName 路径跟文件名

* @return File对象

private static File createFile(String pathNameAndFileName) {

File file = new File(pathNameAndFileName);

try {

//获取父目录

File fileParent = file.getParentFile();

if (!fileParent.exists()) {

fileParent.mkdirs();

}

//创建文件

if (!file.exists()) {

file.createNewFile();

}

} catch (Exception e) {

file = null;

System.err.println("新建文件操作出错");

e.printStackTrace();

}

return file;

}

/**

* 字符流写入文件

* @param file file对象

* @param stringBuffer 要写入的数据

private static void fileWriter(File file, StringBuffer stringBuffer) {

//字符流

try {

FileWriter resultFile = new FileWriter(file, false);//true,则追加写入 false,则覆盖写入

PrintWriter myFile = new PrintWriter(resultFile);

//写入

myFile.println(stringBuffer.toString());

myFile.close();

resultFile.close();

} catch (Exception e) {

System.err.println("写入操作出错");

e.printStackTrace();

}

/**

* 字符串处理工具类

private static class StringUtil {

/**

* 数据库类型->JAVA类型

* @param dbType 数据库类型

* @return JAVA类型

private static String typeMapping(String dbType) {

String javaType;

if ("int|integer".contains(dbType)) {

javaType = "Integer";

} else if ("float|double|decimal|real".contains(dbType)) {

javaType = "Double";

} else if ("date|time|datetime|timestamp".contains(dbType)) {

javaType = "Date";

} else {

javaType = "String";

}

return javaType;

}

/**

* 驼峰转换为下划线

private static String underscoreName(String camelCaseName) {

StringBuilder result = new StringBuilder();

if (camelCaseName != null && camelCaseName.length() > 0) {

result.append(camelCaseName.substring(0, 1).toLowerCase());

for (int i = 1; i < camelCaseName.length(); i++) {

char ch = camelCaseName.charAt(i);

if (Character.isUpperCase(ch)) {

result.append("_");

result.append(Character.toLowerCase(ch));

} else {

result.append(ch);

}

return result.toString();

}

/**

* 首字母大写

private static String captureName(String name) {

char[] cs = name.toCharArray();

cs[0] -= 32;

return String.valueOf(cs);

}

/**

* 下划线转换为驼峰

private static String camelCaseName(String underscoreName) {

StringBuilder result = new StringBuilder();

if (underscoreName != null && underscoreName.length() > 0) {

boolean flag = false;

for (int i = 0; i < underscoreName.length(); i++) {

char ch = underscoreName.charAt(i);

if ("_".charAt(0) == ch) {

flag = true;

} else {

if (flag) {

result.append(Character.toUpperCase(ch));

flag = false;

} else {

result.append(ch);

}

return result.toString();

}

/**

* JDBC连接数据库工具类

private static class DBConnectionUtil {

static {

// 1、加载驱动

try {

Class.forName(DRIVER_CLASSNAME);

} catch (ClassNotFoundException e) {

e.printStackTrace();

}

/**

* 返回一个Connection连接

static Connection getConnection() {

Connection conn = null;

// 2、连接数据库

try {

conn = DriverManager.getConnection(URL, USERNAME, PASSWORD);

} catch (SQLException e) {

e.printStackTrace();

}

return conn;

}

/**

* 关闭Connection，Statement连接

public static void close(Connection conn, Statement stmt) {

try {

conn.close();

stmt.close();

} catch (SQLException e) {

e.printStackTrace();

}

/**

* 关闭Connection，Statement，ResultSet连接

public static void close(Connection conn, Statement stmt, ResultSet rs) {

try {

close(conn, stmt);

rs.close();

} catch (SQLException e) {

e.printStackTrace();

}

/**

* 表结构信息实体类

private class TableInfo {

private String columnName;//字段名

private String dataType;//字段类型

private String columnComment;//字段注释

private String columnKey;//主键

private String extra;//主键类型

public String getColumnName() {

return columnName;

}

public void setColumnName(String columnName) {

this.columnName = columnName;

}

public String getDataType() {

return dataType;

}

public void setDataType(String dataType) {

this.dataType = dataType;

}

public String getColumnComment() {

return columnComment;

}

public void setColumnComment(String columnComment) {

this.columnComment = columnComment;

}

public String getColumnKey() {

return columnKey;

}

public void setColumnKey(String columnKey) {

this.columnKey = columnKey;

}

public String getExtra() {

return extra;

}

public void setExtra(String extra) {

this.extra = extra;

}

/**

* 获取表结构信息

* 目前仅支持mysql

private List getTableInfo() {

Connection conn = null;

PreparedStatement ps = null;

ResultSet rs = null;

ArrayList list = new ArrayList<>();

try {

conn = DBConnectionUtil.getConnection();

//表字段信息

String sql = "select column_name,data_type,column_comment,column_key,extra from information_schema.columns where table_schema = (select database()) and table_name=?";

ps = conn.prepareStatement(sql);

ps.setString(1, tableName);

rs = ps.executeQuery();

while (rs.next()) {

TableInfo tableInfo = new TableInfo();

//列名，全部转为小写

tableInfo.setColumnName(rs.getString("column_name").toLowerCase());

//列类型

tableInfo.setDataType(rs.getString("data_type"));

//列注释

tableInfo.setColumnComment(rs.getString("column_comment"));

//主键

tableInfo.setColumnKey(rs.getString("column_key"));

//主键类型

tableInfo.setExtra(rs.getString("extra"));

list.add(tableInfo);

}

//表注释

sql = "select table_comment from information_schema.tables where table_schema = (select database()) and table_name=?";

ps = conn.prepareStatement(sql);

ps.setString(1, tableName);

rs = ps.executeQuery();

while (rs.next()) {

//表注释

tableComment = rs.getString("table_comment");

}

} catch (SQLException e) {

e.printStackTrace();

} finally {

if(rs != null){

DBConnectionUtil.close(conn, ps, rs);

}

return list;

}

/**

* 快速创建，供外部调用，调用之前先设置一下项目的基础路径

private String create() {

System.out.println("生成路径位置：" + filePath);

//获取表信息

List tableInfo = getTableInfo();

//开始生成代码

createPojo(tableInfo);

createVo(tableInfo);

createRepository(tableInfo);

createService(tableInfo);

createController(tableInfo);

return tableName + " 后台代码生成完毕！";

}

public static void main(String[] args) {

// String[] tables = {"sys_user","sys_menu","sys_authority","sys_user_menu","sys_user_authority","sys_shortcut_menu","sys_setting"};

String[] tables = {"tb_user"};

for (String table : tables) {

String msg = new AutoGenerator(table).create();

System.out.println(msg);

}

v2.0 AutoGeneratorPlus

package cn.huanzi.qch.baseadmin.autogenerator;

import java.io.*;

import java.sql.*;

import java.text.SimpleDateFormat;

import java.util.ArrayList;

import java.util.Date;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

/**

* 代码生成工具 V2.0

public class AutoGeneratorPlus {

/**

* 程序自动设置

private String tableName;//表名

private String tableComment;//表注释

private String filePath;//最终文件生成位置

/**

* 数据连接相关，需要手动设置

private static final String URL = "jdbc:mysql://localhost:3306/test?serverTimezone=GMT%2B8&characterEncoding=utf-8";

private static final String USERNAME = "root";

private static final String PASSWORD = "123456";

private static final String DRIVER_CLASSNAME = "com.mysql.cj.jdbc.Driver";

/**

* 基础路径，需要手动设置

private String tlfPath = System.getProperty("user.dir") + "\\src\\main\\resources\\tlf\\";//模板文件位置

private String basePackage = "cn\\huanzi\\qch\\baseadmin\\";//根包位置

private String filePackage = basePackage + "sys\\";//文件所在包位置

/**

* 构造参数，设置表名

private AutoGeneratorPlus(String tableName) {

//设置表名

this.tableName = tableName;

//文件所在包位置

filePackage = filePackage + StringUtil.camelCaseName(tableName).toLowerCase() + "\\";

//拼接完整最终位置 System.getProperty("user.dir") 获取的是项目所在路径，如果我们是子项目，则需要添加一层路径

filePath = System.getProperty("user.dir") + "\\src\\main\\java\\" + filePackage;

}

/**

* 读取模板，设置内容，生成文件

* @param templatePath 模板文件路径

* @param outputFile 文件生成路径

* @param tableInfos 表字段信息

* @param customParameter 自定义参数

private void writer(String templatePath, String outputFile,List tableInfos,Map customParameter){

//主键

TableInfo prikey = new TableInfo();

//for循环标识

boolean forFlag = false;

StringBuilder forContent = new StringBuilder();

//驼峰标识映射后的表名

String replacement = StringUtil.captureName(StringUtil.camelCaseName(tableName));

//遍历属性

for (TableInfo tableInfo : tableInfos) {

//主键

if ("PRI".equals(tableInfo.getColumnKey())) {

prikey = tableInfo;

break;

}

try(FileReader fileReader = new FileReader(templatePath);

BufferedReader reader = new BufferedReader(fileReader)) {

//生成文件

File file = FileUtil.createFile(outputFile);

StringBuffer stringBuffer = new StringBuffer();

//读取模板文件，拼接文件内容

Object[] lines = reader.lines().toArray();

for (Object o : lines) {

String line = String.valueOf(o);

/* 设置值 */

//${tableName} 表名称，例如：tb_user

if(line.contains("${tableName}")){

line = line.replaceAll("\\$\\{tableName}", tableName);

}

//${tableComment} 表注释，例如：tb_user

if(line.contains("${tableComment}")){

line = line.replaceAll("\\$\\{tableComment}", tableComment);

}

//${entity} 实体类名称，例如：TbUser

if(line.contains("${entity}")){

line = line.replaceAll("\\$\\{entity}", replacement);

}

//${entityFirstToLowerCase} 实体类名称首字母小写，例如：tbUser

if(line.contains("${entityFirstToLowerCase}")){

line = line.replaceAll("\\$\\{entityFirstToLowerCase}", StringUtil.camelCaseName(tableName));

}

//${entityToLowerCase} 实体类名称全小写，例如：tbuser

if(line.contains("${entityToLowerCase}")){

line = line.replaceAll("\\$\\{entityToLowerCase}", replacement.toLowerCase());

}

//${priDataType} 实体类主键类型，例如：String

if(line.contains("${priDataType}")){

line = line.replaceAll("\\$\\{priDataType}", StringUtil.typeMapping(prikey.getDataType()));

}

//处理自定义参数

line = customParameter(line,customParameter);

//先取得循环体的内容

if(forFlag){

forContent.append(line).append("\n");

}

//是否为for循环遍历表字段

if(line.contains("#for")){

forFlag = true;

}

if(line.contains("#end")){

forFlag = false;

line = line.replaceAll("#end", "");

}

//遍历循环体的内容，并设置值

if(!forFlag && forContent.length() > 0){

//遍历表字段

for (TableInfo tableInfo : tableInfos) {

String tableColumns = forContent.toString()

//表字段信息：类型、名称、注释

.replaceAll("\\$\\{tableInfo.dataType}", StringUtil.typeMapping(tableInfo.getDataType()))

.replaceAll("\\$\\{tableInfo.columnName}", StringUtil.camelCaseName(tableInfo.getColumnName()))

.replaceAll("\\$\\{tableInfo.columnComment}", tableInfo.getColumnComment());

//清除多余#end，以及换行符

tableColumns = tableColumns.replaceAll("#end", "").replaceAll("\n", "");

//设置是否主键、是否自增

String pri = "",autoIncrement="";

//主键

if ("PRI".equals(tableInfo.getColumnKey())) {

pri = " @Id\n";

//自增id

if ("auto_increment".equals(tableInfo.getExtra())){

autoIncrement = "@GeneratedValue(strategy= GenerationType.IDENTITY)\n";

}

tableColumns = tableColumns

.replaceAll("#ifPri", pri)

.replaceAll("#ifAutoIncrement", autoIncrement);

//处理自定义参数

tableColumns = customParameter(tableColumns,customParameter);

//前补tab，后补换行符

stringBuffer.append(" ").append(tableColumns.trim()).append("\n\n");

}

//置空

forContent.setLength(0);

}

if(!forFlag){

stringBuffer.append(line).append("\n");

}

//写入数据到到文件中

FileUtil.fileWriter(file, stringBuffer);

}catch (Exception e){

e.printStackTrace();

}

private void writer(String templatePath, String outputFile,List tableInfos){

writer(templatePath,outputFile,tableInfos,new HashMap<>());

}

/**

* 处理自定义参数

private String customParameter(String str,Map customParameter){

for (String key : customParameter.keySet()) {

str = str.replaceAll("\\$\\{"+key+"}",customParameter.get(key));

}

return str;

}

/**

* file工具类

private static class FileUtil {

/**

* 创建文件

* @param pathNameAndFileName 路径跟文件名

* @return File对象

private static File createFile(String pathNameAndFileName) {

File file = new File(pathNameAndFileName);

try {

//获取父目录

File fileParent = file.getParentFile();

if (!fileParent.exists()) {

fileParent.mkdirs();

}

//创建文件

if (!file.exists()) {

file.createNewFile();

}

} catch (Exception e) {

file = null;

System.err.println("新建文件操作出错");

e.printStackTrace();

}

return file;

}

/**

* 字符流写入文件

* @param file file对象

* @param stringBuffer 要写入的数据

private static void fileWriter(File file, StringBuffer stringBuffer) {

//字符流

try {

FileWriter resultFile = new FileWriter(file, false);//true,则追加写入 false,则覆盖写入

PrintWriter myFile = new PrintWriter(resultFile);

//写入

myFile.println(stringBuffer.toString());

myFile.close();

resultFile.close();

} catch (Exception e) {

System.err.println("写入操作出错");

e.printStackTrace();

}

/**

* 字符串处理工具类

private static class StringUtil {

/**

* 数据库类型->JAVA类型

* @param dbType 数据库类型

* @return JAVA类型

private static String typeMapping(String dbType) {

String javaType;

if ("int|integer".contains(dbType)) {

javaType = "Integer";

} else if ("float|double|decimal|real".contains(dbType)) {

javaType = "Double";

} else if ("date|time|datetime|timestamp".contains(dbType)) {

javaType = "Date";

} else {

javaType = "String";

}

return javaType;

}

/**

* 驼峰转换为下划线

private static String underscoreName(String camelCaseName) {

StringBuilder result = new StringBuilder();

if (camelCaseName != null && camelCaseName.length() > 0) {

result.append(camelCaseName.substring(0, 1).toLowerCase());

for (int i = 1; i < camelCaseName.length(); i++) {

char ch = camelCaseName.charAt(i);

if (Character.isUpperCase(ch)) {

result.append("_");

result.append(Character.toLowerCase(ch));

} else {

result.append(ch);

}

return result.toString();

}

/**

* 首字母大写

private static String captureName(String name) {

char[] cs = name.toCharArray();

cs[0] -= 32;

return String.valueOf(cs);

}

/**

* 下划线转换为驼峰

private static String camelCaseName(String underscoreName) {

StringBuilder result = new StringBuilder();

if (underscoreName != null && underscoreName.length() > 0) {

boolean flag = false;

for (int i = 0; i < underscoreName.length(); i++) {

char ch = underscoreName.charAt(i);

if ("_".charAt(0) == ch) {

flag = true;

} else {

if (flag) {

result.append(Character.toUpperCase(ch));

flag = false;

} else {

result.append(ch);

}

return result.toString();

}

/**

* JDBC连接数据库工具类

private static class DBConnectionUtil {

static {

// 1、加载驱动

try {

Class.forName(DRIVER_CLASSNAME);

} catch (ClassNotFoundException e) {

e.printStackTrace();

}

/**

* 返回一个Connection连接

static Connection getConnection() {

Connection conn = null;

// 2、连接数据库

try {

conn = DriverManager.getConnection(URL, USERNAME, PASSWORD);

} catch (SQLException e) {

e.printStackTrace();

}

return conn;

}

/**

* 关闭Connection，Statement连接

public static void close(Connection conn, Statement stmt) {

try {

conn.close();

stmt.close();

} catch (SQLException e) {

e.printStackTrace();

}

/**

* 关闭Connection，Statement，ResultSet连接

public static void close(Connection conn, Statement stmt, ResultSet rs) {

try {

close(conn, stmt);

rs.close();

} catch (SQLException e) {

e.printStackTrace();

}

/**

* 表结构信息实体类

private class TableInfo {

private String columnName;//字段名

private String dataType;//字段类型

private String columnComment;//字段注释

private String columnKey;//主键

private String extra;//主键类型

public String getColumnName() {

return columnName;

}

public void setColumnName(String columnName) {

this.columnName = columnName;

}

public String getDataType() {

return dataType;

}

public void setDataType(String dataType) {

this.dataType = dataType;

}

public String getColumnComment() {

return columnComment;

}

public void setColumnComment(String columnComment) {

this.columnComment = columnComment;

}

public String getColumnKey() {

return columnKey;

}

public void setColumnKey(String columnKey) {

this.columnKey = columnKey;

}

public String getExtra() {

return extra;

}

public void setExtra(String extra) {

this.extra = extra;

}

/**

* 获取表结构信息

* 目前仅支持mysql

private List getTableInfo() {

Connection conn = null;

PreparedStatement ps = null;

ResultSet rs = null;

ArrayList list = new ArrayList<>();

try {

conn = DBConnectionUtil.getConnection();

//表字段信息

String sql = "select column_name,data_type,column_comment,column_key,extra from information_schema.columns where table_schema = (select database()) and table_name=?";

ps = conn.prepareStatement(sql);

ps.setString(1, tableName);

rs = ps.executeQuery();

while (rs.next()) {

TableInfo tableInfo = new TableInfo();

//列名，全部转为小写

tableInfo.setColumnName(rs.getString("column_name").toLowerCase());

//列类型

tableInfo.setDataType(rs.getString("data_type"));

//列注释

tableInfo.setColumnComment(rs.getString("column_comment"));

//主键

tableInfo.setColumnKey(rs.getString("column_key"));

//主键类型

tableInfo.setExtra(rs.getString("extra"));

list.add(tableInfo);

}

//表注释

sql = "select table_comment from information_schema.tables where table_schema = (select database()) and table_name=?";

ps = conn.prepareStatement(sql);

ps.setString(1, tableName);

rs = ps.executeQuery();

while (rs.next()) {

//表注释

tableComment = rs.getString("table_comment");

}

} catch (SQLException e) {

e.printStackTrace();

} finally {

if(rs != null){

DBConnectionUtil.close(conn, ps, rs);

}

return list;

}

/**

* 快速创建，供外部调用，调用之前先设置一下项目的基础路径

private String create() {

System.out.println("生成路径位置：" + filePath);

//获取表信息

List tableInfo = getTableInfo();

//驼峰标识映射后的表名

String captureName = StringUtil.captureName(StringUtil.camelCaseName(tableName));

//自定义参数

HashMap customParameter = new HashMap<>();

customParameter.put("date","生成日期："+new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date()));

//读取模板、生成代码

writer(tlfPath+"controller.tlf",

filePath + "controller\\" + captureName + "Controller.java",

tableInfo,customParameter);

writer(tlfPath+"entity.tlf",

filePath + "pojo\\" + captureName + ".java",

tableInfo,customParameter);

writer(tlfPath+"entityvo.tlf",

filePath + "vo\\" + captureName + "Vo.java",

tableInfo,customParameter);

writer(tlfPath+"repository.tlf",

filePath + "repository\\" + captureName + "Repository.java",

tableInfo,customParameter);

writer(tlfPath+"service.tlf",

filePath + "service\\" + captureName + "Service.java",

tableInfo,customParameter);

writer(tlfPath+"serviceimpl.tlf",

filePath + "service\\" + captureName + "ServiceImpl.java",

tableInfo,customParameter);

return tableName + " 后台代码生成完毕！";

}

public static void main(String[] args) {

// String[] tables = {"sys_user","sys_menu","sys_authority","sys_user_menu","sys_user_authority","sys_shortcut_menu","sys_setting"};

String[] tables = {"tb_user"};

for (String table : tables) {

String msg = new AutoGeneratorPlus(table).create();

System.out.println(msg);

}

同时，所有代码都在base admin项目里，代码已经开源、托管到我的github、码云：

GitHub：https://github.com/huanzi-qch/base-admin

码云：https://gitee.com/huanzi-qch/base-admin

python怎么过滤字符串中的英文字母

248 2023-01-03

教你用Java实现一个简单的代码生成器

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