java读取properties文件

java读取properties文件

关键字: java读取properties配置文件 今天要将以前一个项目的数据连接改成从properties文件中配置。找了好久，网上也不少，可就是读取文件时总是找不到文件在哪（我放在classes目录下了）。最后终于成功，记下，以做纪念。

Java代码

package com.web.connection; import java.io.IOException; import java.io.InputStream; import java.sql.Connection; import java.sql.DriverManager; import java.sql.SQLException; import java.util.Properties; import java.util.logging.Level; import java.util.logging.Logger; public class Conn { private String fileName="/db.properties";//这里是指放在classes下，如果有包的话，前面加包名即可。例：/com/web/db.properties private String driver = ""; private String url = ""; private String username =""; private String password = ""; Connection conn=null; public Connection getConn(){ Properties p = new Properties(); try { InputStream in = Conn.class.getResourceAsStream(fileName);// 与类在同一级，也可用/package/path/to/fileName p.load(in); in.close(); if(p.containsKey("driver")){ this.driver = p.getProperty("driver"); } if(p.containsKey("url")){ this.url = p.getProperty("url"); } if(p.containsKey("user")){ this.username = p.getProperty("user"); } if(p.containsKey("password")){ this.password = p.getProperty("password"); } } catch (IOException ex) { Logger.getLogger(Conn.class.getName()).log(Level.SEVERE, null, ex); } System.out.println(p.getProperty("driver")); try { Class.forName(this.driver); conn = DriverManager.getConnection(this.url,this.username,this.password); } catch (SQLException ex) { ex.printStackTrace(); System.out.print("获取连接异常"); } catch (ClassNotFoundException ex) { System.out.print("加载驱动出错"); ex.printStackTrace();; } return conn; } } package com.web.connection; import java.io.IOException; import java.io.InputStream; import java.sql.Connection; import java.sql.DriverManager; import java.sql.SQLException; import java.util.Properties; import java.util.logging.Level; import java.util.logging.Logger; public class Conn { private String fileName="/db.properties";//这里是指放在classes下，如果有包的话，前面加包名即可。例：/com/web/db.properties private String driver = ""; private String url = ""; private String username =""; private String password = ""; Connection conn=null; public Connection getConn(){ Properties p = new Properties(); try { InputStream in = Conn.class.getResourceAsStream(fileName);//这里有人用new FileInputStream(fileName),不过这种方式找不到配置文件。有人说是在classes下，我调过了，不行。 p.load(in); in.close(); if(p.containsKey("driver")){ this.driver = p.getProperty("driver"); } if(p.containsKey("url")){ this.url = p.getProperty("url"); } if(p.containsKey("user")){ this.username = p.getProperty("user"); } if(p.containsKey("password")){ this.password = p.getProperty("password"); } } catch (IOException ex) { Logger.getLogger(Conn.class.getName()).log(Level.SEVERE, null, ex); } System.out.println(p.getProperty("driver")); try { Class.forName(this.driver); conn = DriverManager.getConnection(this.url,this.username,this.password); } catch (SQLException ex) { ex.printStackTrace(); System.out.print("获取连接异常"); } catch (ClassNotFoundException ex) { System.out.print("加载驱动出错"); ex.printStackTrace();; } return conn; } } 网上文章常见的几种读取.properties文件的方式 1、使用java.util.Properties类的load()方法 示例： Java代码 1. InputStream in = lnew BufferedInputStream(new2. Properties p = new3. p.load(in); InputStream in = lnew BufferedInputStream(new FileInputStream(name)); Properties p = new Properties(); p.load(in);2、使用java.util.ResourceBundle类的getBundle()方法 示例： Java代码 1. ResourceBundle rb = ResourceBundle.getBundle(name, Locale.getDefault()); ResourceBundle rb = ResourceBundle.getBundle(name, Locale.getDefault());用ResourceBundle读取.properties文件可避免路径问题 我在jar里读取.properties文件时，总是找不到文件路径，后来用ResourceBundle读取.properties文件即可避免路径问题，代码如下： //process为文件名，切记不要加 .properties， URL是文件里的键名 Java代码 1. getBundle("com.ihandy.smsoc.app.process");2. "URL");3. System.out.println(s);4. pURL = s; ResourceBundle bundle = ResourceBundle.getBundle("com.ihandy.smsoc.app.process"); String s = bundle.getString("URL"); System.out.println(s); pURL = s;3、使用java.util.PropertyResourceBundle类的构造函数 示例： Java代码 1. InputStream in = new BufferedInputStream(new2. ResourceBundle rb = new InputStream in = new BufferedInputStream(new FileInputStream(name)); ResourceBundle rb = new PropertyResourceBundle(in);4、使用class变量的getResourceAsStream()方法 示例： Java代码 1. InputStream in = 类名.class.getResourceAsStream(name);2. Properties p = new3. p.load(in); InputStream in = 类名.class.getResourceAsStream(name); Properties p = new Properties(); p.load(in);5、使用class.getClassLoader()所得到的java.lang.ClassLoader的getResourceAsStream()方法 示例： Java代码 1. InputStream in = 类名.class.getClassLoader().getResourceAsStream(name);2. Properties p = new3. p.load(in); InputStream in = 类名.class.getClassLoader().getResourceAsStream(name); Properties p = new Properties(); p.load(in);6、使用java.lang.ClassLoader类的getSystemResourceAsStream()静态方法 示例： Java代码 1. InputStream in = ClassLoader.getSystemResourceAsStream(name);2. Properties p = new3. p.load(in); InputStream in = ClassLoader.getSystemResourceAsStream(name); Properties p = new Properties(); p.load(in);7、Servlet中可以使用javax.servlet.ServletContext的getResourceAsStream()方法 示例： Java代码 1. InputStream in = context.getResourceAsStream(path);2. Properties p = new3. p.load(in);

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