Java实现文件的分割与合并-APISpace

Java实现文件的分割与合并

本文实例为大家分享了java实现文件的分割与合并的具体代码，供大家参考，具体内容如下

一、文件分割实现思想

1、设置分割文件（块）的大小；

2、通过输入流获取源文件的大小；

3、根据1、2步的计算结果计算出分割后的文件个数（源文件的大小 / 设置分割文件的大小，如果设置的文件大小大于源文件的大小，接下来判断1、2步计算结果，如果余数为0，则文件个数为商值，如果余数大于0，则文件个数为商值加1。

如果设置分割文件的大小小于源文件的大小，那么文件个数为1。）；

4、分割文件（边读边写）。

二、文件合并实现思想

1、文件合并与文件分割实现思想的第4步类似，就是边读边写。

方式一：调用API中的RandomAccessFile，此类的实例支持对随机存取文件的读取和写入。按块分割与合并，示例代码如下：

package com.cn.filesplite1;

import java.io.BufferedInputStream;

import java.io.BufferedOutputStream;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileNotFoundException;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.InputStream;

import java.io.RandomAccessFile;

import java.io.SequenceInputStream;

import java.util.ArrayList;

import java.util.List;

import java.util.Vector;

public class SplitFile {

//文件的路径

private String filePath;

//文件名

private String fileName;

//文件大小

private long length;

//块数

private int size;

//每块的大小

private long blockSize;

//分割后的存放目录

private String destBlockPath;

//每块的名称

private List blockPath;

public SplitFile(){

blockPath = new ArrayList();

}

public SplitFile(String filePath,String destBlockPath){

this(filePath,destBlockPath,1024);

}

public SplitFile(String filePath,String destBlockPath,long blockSize){

this();

this.filePath= filePath;

this.destBlockPath =destBlockPath;

this.blockSize=blockSize;

init();

}

/**

* 初始化操作计算块数、确定文件名

public void init(){

File src =null;

//健壮性

if(null==filePath ||!(((src=new File(filePath)).exists()))){

return;

}

if(src.isDirectory()){

return ;

}

//文件名

this.fileName =src.getName();

//计算块数实际大小与每块大小

this.length = src.length();

//修正每块大小

if(this.blockSize>length){

this.blockSize =length;

}

//确定块数

size= (int)(Math.ceil(length*1.0/this.blockSize));

//确定文件的路径

initPathName();

}

private void initPathName(){

for(int i=0;i

this.blockPath.add(destBlockPath+"/"+this.fileName+".part"+i);

}

/**

* 文件的分割

* 0)、第几块

* 1、起始位置

* 2、实际大小

* @param destPath 分割文件存放目录

public void split(){

long beginPos =0; //起始点

long actualBlockSize =blockSize; //实际大小

//计算所有块的大小、位置、索引

for(int i=0;i

if(i==size-1){ //最后一块

actualBlockSize =this.length-beginPos;

}

spiltDetail(i,beginPos,actualBlockSize);

beginPos+=actualBlockSize; //本次的终点，下一次的起点

}

/**

* 文件的分割输入输出

* 文件拷贝

* @param idx 第几块

* @param beginPos 起始点

* @param actualBlockSize 实际大小

private void spiltDetail(int idx,long beginPos,long actualBlockSize){

//1、创建源

File src = new File(this.filePath); //源文件

File dest = new File(this.blockPath.get(idx)); //目标文件

//2、选择流

RandomAccessFile raf = null; //输入流

BufferedOutputStream bos=null; //输出流

try {

raf=new RandomAccessFile(src,"r");

bos =new BufferedOutputStream(new FileOutputStream(dest));

//读取文件

raf.seek(beginPos);

//缓冲区

byte[] flush = new byte[1024];

//接收长度

int len =0;

while(-1!=(len=raf.read(flush))){

if(actualBlockSize-len>=0){ //查看是否足够

//写出

bos.write(flush, 0, len);

actualBlockSize-=len; //剩余量

}else{ //写出最后一次的剩余量

bos.write(flush, 0, (int)actualBlockSize);

break;

}

} catch (FileNotFoundException e) {

e.printStackTrace();

} catch (IOException e) {

e.printStackTrace();

}finally{

FileUtil.close(bos,raf);

}

/**

* 文件的合并

public void merge(String destPath){

//创建源

File dest =new File(destPath);

//选择流

BufferedOutputStream bos=null; //输出流

SequenceInputStream sis =null ;//输入流

//创建一个容器

Vector vi = new Vector();

try {

for (int i = 0; i < this.blockPath.size(); i++) {

vi.add(new BufferedInputStream(new FileInputStream(new File(this.blockPath.get(i)))));

}

bos =new BufferedOutputStream(new FileOutputStream(dest,true)); //追加

sis=new SequenceInputStream(vi.elements());

//缓冲区

byte[] flush = new byte[1024];

//接收长度

int len =0;

while(-1!=(len=sis.read(flush))){

bos.write(flush, 0, len);

}

bos.flush();

FileUtil.close(sis);

} catch (Exception e) {

}finally{

FileUtil.close(bos);

}

/**

* @param args

public static void main(String[] args) {

//1024 * 30 表示按照每块30Kb大小分割

SplitFile split = new SplitFile("F:/123/1234/logFile.txt","F:/123/",1024 * 30);

System.out.println(split.size);

// split.split();

split.merge("F:/123/logFile.txt");

}

package com.cn.filesplite1;

import java.io.Closeable;

public class FileUtil {

/**

* 工具类关闭流

* 可变参数: ... 只能形参最后一个位置,处理方式与数组一致

public static void close(Closeable ... io){

for(Closeable temp:io){

try {

if (null != temp) {

temp.close();

}

} catch (Exception e) {

}

/**

* 使用泛型方法

public static void closeAll(T ... io){

for(Closeable temp:io){

try {

if (null != temp) {

temp.close();

}

} catch (Exception e) {

}

方式二：用读写的方式实现文件的分割与合并，具体实现如下代码所示：

定义一个抽象类

package com.cn.filesplite2;

import java.io.File;

import java.io.IOException;

/**

* 文件分割

* @author Administrator

public abstract class SplitFile {

/**

* 设置单个文件的大小

* 根据自己需求设置大小，字节进率为1024，本例中设置的最http://大分割文件大小是2Gb。

public static long MAX_BYTE = 1024 * 1024 * 1024 * 2L; //2G

/**

* 获取可以分割的文件数

* @param fileByte 文件大小

* @param fileParh 文件路径

* @return

public abstract int getSplitFileNum(long fileByte,String fileParh);

/**

* 获取文件长度

* @param file

* @return

* @throws IOException

public abstract long getFileLength(File file) ;

/**

* 分割文件

* @param srcFile

* @param splitFileNum

* @return

* @throws IOException

public abstract String[] splitFile (File srcFile,int splitFileNum) throws IOException;

/**

* 合并文件

* @param files

* @param newFile

* @throws IOException

public abstract void mergeFile(String[] files,String newFile) throws IOException;

}

实现类

package com.cn.filesplite2;

import java.io.BufferedReader;

import java.io.BufferedWriter;

import java.io.File;

import java.io.FileReader;

import java.io.FileWriter;

import java.io.IOException;

/**

* 文本文件分割

* @author Administrator

public class SplitTextFile extends SplitFile{

@Override

public long getFileLength(File file) {

FileReader fr = null;

BufferedReader br = null;

//文件大小

long fileSize = 0;

try {

fr = new FileReader(file);

br = new BufferedReader(fr);

String line = br.readLine();

//按行读取文件

while(line != null){

//计算文件大小

fileSize += line.length();

line = br.readLine();

}

} catch (IOException e) {

e.printStachttp://kTrace();

}finally{

//关闭输入流

try {

if(br != null){

br.close();

}

if(fr != null){

fr.close();

}

} catch (IOException e) {

e.printStackTrace();

}

//返回文件大小

return fileSize;

}

@Override

public int getSplitFileNum(long fileByte,String fileParh){

fileByte = getFileLength(new File(fileParh));

if(MAX_BYTE < fileByte){

if(fileByte % MAX_BYTE == 0){

return (int) (fileByte/MAX_BYTE);

}else{

return (int) (fileByte/MAX_BYTE) + 1;

}

return 1;

}

@Override

public String[] splitFile(File srcFile, int splitFileNum) throws IOException {

splitFileNum = getSplitFileNum(getFileLength(srcFile), srcFile.toString());

if(splitFileNum <= 0){

return null;

}

FileReader fr = null;

BufferedReader br = null;

long readNum = 0;

String[] splits = new String[splitFileNum];

try {

fr = new FileReader(srcFile);

br = new BufferedReader(fr);

int i = 0;

while(splitFileNum > i){

//分割后的文件名

String name = null;

//文件后缀

String nameLast = null;

if(srcFile.getName().indexOf(".") != -1){

name = srcFile.getName().substring(0, srcFile.getName().indexOf("."));

int last = srcFile.getName().lastIndexOf(".");

// System.out.println(i);

// String string = str.substring(i);

nameLast = srcFile.getName().substring(last);

}else{

name = srcFile.getName();

}

splits[i] = srcFile.getParent() + "/" + name + "_" + i + nameLast;

File wfile = new File(splits[i]);

if(!wfile.exists()){

wfile.getParentFile().mkdirs();

wfile.createNewFile();

}

FileWriter fw = new FileWriter(wfile,false);

BufferedWriter bw = new BufferedWriter(fw);

String line = br.readLine();

int flush = 0;

while(line != null){

if(line.trim().length() == 0){

line = br.readLine();

continue;

}

readNum += line.length();

if(i + 1 == splitFileNum){

bw.write(line);

bw.newLine();

}else{

if(readNum >= MAX_BYTE){

bw.write(line);

bw.newLine();

break;

}else{

bw.write(line);

bw.newLine();

}

line = br.readLine();

if(flush % 100 == 0){

bw.flush();

}

bw.flush();

fw.flush();

bw.close();

fw.close();

readNum = 0;

i++;

}

} catch (RuntimeException e) {

e.printStackTrace();

}

finally{

try {

if(br != null) br.close();

if(fr != null) fr.close();

} catch (Exception e) {

e.printStackTrace();

}finally{

br = null;

fr = null;

}

return splits;

}

@Override

public void mergeFile(String[] files, String newFile) throws IOException {

File wfile = new File(newFile);

FileWriter writer = null;

BufferedWriter bufferedWriter = null;

try {

writer = new FileWriter(wfile,false);

bufferedWriter = new BufferedWriter(writer);

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

File rFile = new File(files[i]);

FileReader reader = new FileReader(rFile);

BufferedReader bufferedReader = new BufferedReader(reader);

String line = bufferedReader.readLine();

while(line != null){

if(line.trim().length() == 0){

line = bufferedReader.readLine();

continue;

}

bufferedWriter.write(line);

bufferedWriter.newLine();

line = bufferedReader.readLine();

}

bufferedWriter.flush();

writer.flush();

} catch (Exception e) {

e.printStackTrace();

}finally{

if(bufferedWriter != null)

bufferedWriter.close();

bufferedWriter = null;

if(writer != null)

writer.close();

writer = null;

}

IxIZf

测试类

package com.cn.filesplite2;

import java.io.File;

import java.io.IOException;

import org.junit.Test;

public class TestSplitFile {

SplitTextFile splitTextFile = new SplitTextFile();

@Test

public void funSplitFile() throws IOException{

String srcPath = "E:/splitfile/splitfile.txt";

File file = new File(srcPath);

long fileLength = splitTextFile.getFileLength(file);

System.out.println("文件大小：" + fileLength);

int partitionFileNum = splitTextFile.getSplitFileNum(fileLength, srcPath);

System.out.println("个数" + partitionFileNum);

//文件分割

splitTextFile.splitFile(new File(srcPath), partitionFileNum);

}

@Test

public void funMergeFile() throws IOException{

String[] files = {"E:/splitfile/splitfile0",

"E:/splitfile/splitfile1",

"E:/splitfile/splitfile2"

// ...files/

};

String newFile = "E:/splitfile/newmergefile";

splitTextFile.mergeFile(files, newFile);

}

以上内容如有任何问题或错误，恳请大家能给予意见，我会及时更正，谢谢大家。

this.blockPath.add(destBlockPath+"/"+this.fileName+".part"+i);

}

/**

* 文件的分割

* 0)、第几块

* 1、起始位置

* 2、实际大小

* @param destPath 分割文件存放目录

public void split(){

long beginPos =0; //起始点

long actualBlockSize =blockSize; //实际大小

//计算所有块的大小、位置、索引

for(int i=0;i

if(i==size-1){ //最后一块

actualBlockSize =this.length-beginPos;

}

spiltDetail(i,beginPos,actualBlockSize);

beginPos+=actualBlockSize; //本次的终点，下一次的起点

}

/**

* 文件的分割输入输出

* 文件拷贝

* @param idx 第几块

* @param beginPos 起始点

* @param actualBlockSize 实际大小

private void spiltDetail(int idx,long beginPos,long actualBlockSize){

//1、创建源

File src = new File(this.filePath); //源文件

File dest = new File(this.blockPath.get(idx)); //目标文件

//2、选择流

RandomAccessFile raf = null; //输入流

BufferedOutputStream bos=null; //输出流

try {

raf=new RandomAccessFile(src,"r");

bos =new BufferedOutputStream(new FileOutputStream(dest));

//读取文件

raf.seek(beginPos);

//缓冲区

byte[] flush = new byte[1024];

//接收长度

int len =0;

while(-1!=(len=raf.read(flush))){

if(actualBlockSize-len>=0){ //查看是否足够

//写出

bos.write(flush, 0, len);

actualBlockSize-=len; //剩余量

}else{ //写出最后一次的剩余量

bos.write(flush, 0, (int)actualBlockSize);

break;

}

} catch (FileNotFoundException e) {

e.printStackTrace();

} catch (IOException e) {

e.printStackTrace();

}finally{

FileUtil.close(bos,raf);

}

/**

* 文件的合并

public void merge(String destPath){

//创建源

File dest =new File(destPath);

//选择流

BufferedOutputStream bos=null; //输出流

SequenceInputStream sis =null ;//输入流

//创建一个容器

Vector vi = new Vector();

try {

for (int i = 0; i < this.blockPath.size(); i++) {

vi.add(new BufferedInputStream(new FileInputStream(new File(this.blockPath.get(i)))));

}

bos =new BufferedOutputStream(new FileOutputStream(dest,true)); //追加

sis=new SequenceInputStream(vi.elements());

//缓冲区

byte[] flush = new byte[1024];

//接收长度

int len =0;

while(-1!=(len=sis.read(flush))){

bos.write(flush, 0, len);

}

bos.flush();

FileUtil.close(sis);

} catch (Exception e) {

}finally{

FileUtil.close(bos);

}

/**

* @param args

public static void main(String[] args) {

//1024 * 30 表示按照每块30Kb大小分割

SplitFile split = new SplitFile("F:/123/1234/logFile.txt","F:/123/",1024 * 30);

System.out.println(split.size);

// split.split();

split.merge("F:/123/logFile.txt");

}

package com.cn.filesplite1;

import java.io.Closeable;

public class FileUtil {

/**

* 工具类关闭流

* 可变参数: ... 只能形参最后一个位置,处理方式与数组一致

public static void close(Closeable ... io){

for(Closeable temp:io){

try {

if (null != temp) {

temp.close();

}

} catch (Exception e) {

}

/**

* 使用泛型方法

public static void closeAll(T ... io){

for(Closeable temp:io){

try {

if (null != temp) {

temp.close();

}

} catch (Exception e) {

}

方式二：用读写的方式实现文件的分割与合并，具体实现如下代码所示：

定义一个抽象类

package com.cn.filesplite2;

import java.io.File;

import java.io.IOException;

/**

* 文件分割

* @author Administrator

public abstract class SplitFile {

/**

* 设置单个文件的大小

* 根据自己需求设置大小，字节进率为1024，本例中设置的最http://大分割文件大小是2Gb。

public static long MAX_BYTE = 1024 * 1024 * 1024 * 2L; //2G

/**

* 获取可以分割的文件数

* @param fileByte 文件大小

* @param fileParh 文件路径

* @return

public abstract int getSplitFileNum(long fileByte,String fileParh);

/**

* 获取文件长度

* @param file

* @return

* @throws IOException

public abstract long getFileLength(File file) ;

/**

* 分割文件

* @param srcFile

* @param splitFileNum

* @return

* @throws IOException

public abstract String[] splitFile (File srcFile,int splitFileNum) throws IOException;

/**

* 合并文件

* @param files

* @param newFile

* @throws IOException

public abstract void mergeFile(String[] files,String newFile) throws IOException;

}

实现类

package com.cn.filesplite2;

import java.io.BufferedReader;

import java.io.BufferedWriter;

import java.io.File;

import java.io.FileReader;

import java.io.FileWriter;

import java.io.IOException;

/**

* 文本文件分割

* @author Administrator

public class SplitTextFile extends SplitFile{

@Override

public long getFileLength(File file) {

FileReader fr = null;

BufferedReader br = null;

//文件大小

long fileSize = 0;

try {

fr = new FileReader(file);

br = new BufferedReader(fr);

String line = br.readLine();

//按行读取文件

while(line != null){

//计算文件大小

fileSize += line.length();

line = br.readLine();

}

} catch (IOException e) {

e.printStachttp://kTrace();

}finally{

//关闭输入流

try {

if(br != null){

br.close();

}

if(fr != null){

fr.close();

}

} catch (IOException e) {

e.printStackTrace();

}

//返回文件大小

return fileSize;

}

@Override

public int getSplitFileNum(long fileByte,String fileParh){

fileByte = getFileLength(new File(fileParh));

if(MAX_BYTE < fileByte){

if(fileByte % MAX_BYTE == 0){

return (int) (fileByte/MAX_BYTE);

}else{

return (int) (fileByte/MAX_BYTE) + 1;

}

return 1;

}

@Override

public String[] splitFile(File srcFile, int splitFileNum) throws IOException {

splitFileNum = getSplitFileNum(getFileLength(srcFile), srcFile.toString());

if(splitFileNum <= 0){

return null;

}

FileReader fr = null;

BufferedReader br = null;

long readNum = 0;

String[] splits = new String[splitFileNum];

try {

fr = new FileReader(srcFile);

br = new BufferedReader(fr);

int i = 0;

while(splitFileNum > i){

//分割后的文件名

String name = null;

//文件后缀

String nameLast = null;

if(srcFile.getName().indexOf(".") != -1){

name = srcFile.getName().substring(0, srcFile.getName().indexOf("."));

int last = srcFile.getName().lastIndexOf(".");

// System.out.println(i);

// String string = str.substring(i);

nameLast = srcFile.getName().substring(last);

}else{

name = srcFile.getName();

}

splits[i] = srcFile.getParent() + "/" + name + "_" + i + nameLast;

File wfile = new File(splits[i]);

if(!wfile.exists()){

wfile.getParentFile().mkdirs();

wfile.createNewFile();

}

FileWriter fw = new FileWriter(wfile,false);

BufferedWriter bw = new BufferedWriter(fw);

String line = br.readLine();

int flush = 0;

while(line != null){

if(line.trim().length() == 0){

line = br.readLine();

continue;

}

readNum += line.length();

if(i + 1 == splitFileNum){

bw.write(line);

bw.newLine();

}else{

if(readNum >= MAX_BYTE){

bw.write(line);

bw.newLine();

break;

}else{

bw.write(line);

bw.newLine();

}

line = br.readLine();

if(flush % 100 == 0){

bw.flush();

}

bw.flush();

fw.flush();

bw.close();

fw.close();

readNum = 0;

i++;

}

} catch (RuntimeException e) {

e.printStackTrace();

}

finally{

try {

if(br != null) br.close();

if(fr != null) fr.close();

} catch (Exception e) {

e.printStackTrace();

}finally{

br = null;

fr = null;

}

return splits;

}

@Override

public void mergeFile(String[] files, String newFile) throws IOException {

File wfile = new File(newFile);

FileWriter writer = null;

BufferedWriter bufferedWriter = null;

try {

writer = new FileWriter(wfile,false);

bufferedWriter = new BufferedWriter(writer);

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

File rFile = new File(files[i]);

FileReader reader = new FileReader(rFile);

BufferedReader bufferedReader = new BufferedReader(reader);

String line = bufferedReader.readLine();

while(line != null){

if(line.trim().length() == 0){

line = bufferedReader.readLine();

continue;

}

bufferedWriter.write(line);

bufferedWriter.newLine();

line = bufferedReader.readLine();

}

bufferedWriter.flush();

writer.flush();

} catch (Exception e) {

e.printStackTrace();

}finally{

if(bufferedWriter != null)

bufferedWriter.close();

bufferedWriter = null;

if(writer != null)

writer.close();

writer = null;

}

IxIZf

测试类

package com.cn.filesplite2;

import java.io.File;

import java.io.IOException;

import org.junit.Test;

public class TestSplitFile {

SplitTextFile splitTextFile = new SplitTextFile();

@Test

public void funSplitFile() throws IOException{

String srcPath = "E:/splitfile/splitfile.txt";

File file = new File(srcPath);

long fileLength = splitTextFile.getFileLength(file);

System.out.println("文件大小：" + fileLength);

int partitionFileNum = splitTextFile.getSplitFileNum(fileLength, srcPath);

System.out.println("个数" + partitionFileNum);

//文件分割

splitTextFile.splitFile(new File(srcPath), partitionFileNum);

}

@Test

public void funMergeFile() throws IOException{

String[] files = {"E:/splitfile/splitfile0",

"E:/splitfile/splitfile1",

"E:/splitfile/splitfile2"

// ...files/

};

String newFile = "E:/splitfile/newmergefile";

splitTextFile.mergeFile(files, newFile);

}

以上内容如有任何问题或错误，恳请大家能给予意见，我会及时更正，谢谢大家。

if(i==size-1){ //最后一块

actualBlockSize =this.length-beginPos;

}

spiltDetail(i,beginPos,actualBlockSize);

beginPos+=actualBlockSize; //本次的终点，下一次的起点

}

/**

* 文件的分割输入输出

* 文件拷贝

* @param idx 第几块

* @param beginPos 起始点

* @param actualBlockSize 实际大小

private void spiltDetail(int idx,long beginPos,long actualBlockSize){

//1、创建源

File src = new File(this.filePath); //源文件

File dest = new File(this.blockPath.get(idx)); //目标文件

//2、选择流

RandomAccessFile raf = null; //输入流

BufferedOutputStream bos=null; //输出流

try {

raf=new RandomAccessFile(src,"r");

bos =new BufferedOutputStream(new FileOutputStream(dest));

//读取文件

raf.seek(beginPos);

//缓冲区

byte[] flush = new byte[1024];

//接收长度

int len =0;

while(-1!=(len=raf.read(flush))){

if(actualBlockSize-len>=0){ //查看是否足够

//写出

bos.write(flush, 0, len);

actualBlockSize-=len; //剩余量

}else{ //写出最后一次的剩余量

bos.write(flush, 0, (int)actualBlockSize);

break;

}

} catch (FileNotFoundException e) {

e.printStackTrace();

} catch (IOException e) {

e.printStackTrace();

}finally{

FileUtil.close(bos,raf);

}

/**

* 文件的合并

public void merge(String destPath){

//创建源

File dest =new File(destPath);

//选择流

BufferedOutputStream bos=null; //输出流

SequenceInputStream sis =null ;//输入流

//创建一个容器

Vector vi = new Vector();

try {

for (int i = 0; i < this.blockPath.size(); i++) {

vi.add(new BufferedInputStream(new FileInputStream(new File(this.blockPath.get(i)))));

}

bos =new BufferedOutputStream(new FileOutputStream(dest,true)); //追加

sis=new SequenceInputStream(vi.elements());

//缓冲区

byte[] flush = new byte[1024];

//接收长度

int len =0;

while(-1!=(len=sis.read(flush))){

bos.write(flush, 0, len);

}

bos.flush();

FileUtil.close(sis);

} catch (Exception e) {

}finally{

FileUtil.close(bos);

}

/**

* @param args

public static void main(String[] args) {

//1024 * 30 表示按照每块30Kb大小分割

SplitFile split = new SplitFile("F:/123/1234/logFile.txt","F:/123/",1024 * 30);

System.out.println(split.size);

// split.split();

split.merge("F:/123/logFile.txt");

}

package com.cn.filesplite1;

import java.io.Closeable;

public class FileUtil {

/**

* 工具类关闭流

* 可变参数: ... 只能形参最后一个位置,处理方式与数组一致

public static void close(Closeable ... io){

for(Closeable temp:io){

try {

if (null != temp) {

temp.close();

}

} catch (Exception e) {

}

/**

* 使用泛型方法

public static void closeAll(T ... io){

for(Closeable temp:io){

try {

if (null != temp) {

temp.close();

}

} catch (Exception e) {

}

方式二：用读写的方式实现文件的分割与合并，具体实现如下代码所示：

定义一个抽象类

package com.cn.filesplite2;

import java.io.File;

import java.io.IOException;

/**

* 文件分割

* @author Administrator

public abstract class SplitFile {

/**

* 设置单个文件的大小

* 根据自己需求设置大小，字节进率为1024，本例中设置的最http://大分割文件大小是2Gb。

public static long MAX_BYTE = 1024 * 1024 * 1024 * 2L; //2G

/**

* 获取可以分割的文件数

* @param fileByte 文件大小

* @param fileParh 文件路径

* @return

public abstract int getSplitFileNum(long fileByte,String fileParh);

/**

* 获取文件长度

* @param file

* @return

* @throws IOException

public abstract long getFileLength(File file) ;

/**

* 分割文件

* @param srcFile

* @param splitFileNum

* @return

* @throws IOException

public abstract String[] splitFile (File srcFile,int splitFileNum) throws IOException;

/**

* 合并文件

* @param files

* @param newFile

* @throws IOException

public abstract void mergeFile(String[] files,String newFile) throws IOException;

}

实现类

package com.cn.filesplite2;

import java.io.BufferedReader;

import java.io.BufferedWriter;

import java.io.File;

import java.io.FileReader;

import java.io.FileWriter;

import java.io.IOException;

/**

* 文本文件分割

* @author Administrator

public class SplitTextFile extends SplitFile{

@Override

public long getFileLength(File file) {

FileReader fr = null;

BufferedReader br = null;

//文件大小

long fileSize = 0;

try {

fr = new FileReader(file);

br = new BufferedReader(fr);

String line = br.readLine();

//按行读取文件

while(line != null){

//计算文件大小

fileSize += line.length();

line = br.readLine();

}

} catch (IOException e) {

e.printStachttp://kTrace();

}finally{

//关闭输入流

try {

if(br != null){

br.close();

}

if(fr != null){

fr.close();

}

} catch (IOException e) {

e.printStackTrace();

}

//返回文件大小

return fileSize;

}

@Override

public int getSplitFileNum(long fileByte,String fileParh){

fileByte = getFileLength(new File(fileParh));

if(MAX_BYTE < fileByte){

if(fileByte % MAX_BYTE == 0){

return (int) (fileByte/MAX_BYTE);

}else{

return (int) (fileByte/MAX_BYTE) + 1;

}

return 1;

}

@Override

public String[] splitFile(File srcFile, int splitFileNum) throws IOException {

splitFileNum = getSplitFileNum(getFileLength(srcFile), srcFile.toString());

if(splitFileNum <= 0){

return null;

}

FileReader fr = null;

BufferedReader br = null;

long readNum = 0;

String[] splits = new String[splitFileNum];

try {

fr = new FileReader(srcFile);

br = new BufferedReader(fr);

int i = 0;

while(splitFileNum > i){

//分割后的文件名

String name = null;

//文件后缀

String nameLast = null;

if(srcFile.getName().indexOf(".") != -1){

name = srcFile.getName().substring(0, srcFile.getName().indexOf("."));

int last = srcFile.getName().lastIndexOf(".");

// System.out.println(i);

// String string = str.substring(i);

nameLast = srcFile.getName().substring(last);

}else{

name = srcFile.getName();

}

splits[i] = srcFile.getParent() + "/" + name + "_" + i + nameLast;

File wfile = new File(splits[i]);

if(!wfile.exists()){

wfile.getParentFile().mkdirs();

wfile.createNewFile();

}

FileWriter fw = new FileWriter(wfile,false);

BufferedWriter bw = new BufferedWriter(fw);

String line = br.readLine();

int flush = 0;

while(line != null){

if(line.trim().length() == 0){

line = br.readLine();

continue;

}

readNum += line.length();

if(i + 1 == splitFileNum){

bw.write(line);

bw.newLine();

}else{

if(readNum >= MAX_BYTE){

bw.write(line);

bw.newLine();

break;

}else{

bw.write(line);

bw.newLine();

}

line = br.readLine();

if(flush % 100 == 0){

bw.flush();

}

bw.flush();

fw.flush();

bw.close();

fw.close();

readNum = 0;

i++;

}

} catch (RuntimeException e) {

e.printStackTrace();

}

finally{

try {

if(br != null) br.close();

if(fr != null) fr.close();

} catch (Exception e) {

e.printStackTrace();

}finally{

br = null;

fr = null;

}

return splits;

}

@Override

public void mergeFile(String[] files, String newFile) throws IOException {

File wfile = new File(newFile);

FileWriter writer = null;

BufferedWriter bufferedWriter = null;

try {

writer = new FileWriter(wfile,false);

bufferedWriter = new BufferedWriter(writer);

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

File rFile = new File(files[i]);

FileReader reader = new FileReader(rFile);

BufferedReader bufferedReader = new BufferedReader(reader);

String line = bufferedReader.readLine();

while(line != null){

if(line.trim().length() == 0){

line = bufferedReader.readLine();

continue;

}

bufferedWriter.write(line);

bufferedWriter.newLine();

line = bufferedReader.readLine();

}

bufferedWriter.flush();

writer.flush();

} catch (Exception e) {

e.printStackTrace();

}finally{

if(bufferedWriter != null)

bufferedWriter.close();

bufferedWriter = null;

if(writer != null)

writer.close();

writer = null;

}

IxIZf

测试类

package com.cn.filesplite2;

import java.io.File;

import java.io.IOException;

import org.junit.Test;

public class TestSplitFile {

SplitTextFile splitTextFile = new SplitTextFile();

@Test

public void funSplitFile() throws IOException{

String srcPath = "E:/splitfile/splitfile.txt";

File file = new File(srcPath);

long fileLength = splitTextFile.getFileLength(file);

System.out.println("文件大小：" + fileLength);

int partitionFileNum = splitTextFile.getSplitFileNum(fileLength, srcPath);

System.out.println("个数" + partitionFileNum);

//文件分割

splitTextFile.splitFile(new File(srcPath), partitionFileNum);

}

@Test

public void funMergeFile() throws IOException{

String[] files = {"E:/splitfile/splitfile0",

"E:/splitfile/splitfile1",

"E:/splitfile/splitfile2"

// ...files/

};

String newFile = "E:/splitfile/newmergefile";

splitTextFile.mergeFile(files, newFile);

}

以上内容如有任何问题或错误，恳请大家能给予意见，我会及时更正，谢谢大家。

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