先贴代码：

package test;

import java.io.BufferedReader;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileNotFoundException;

import java.io.FileWriter;

import java.io.FilenameFilter;

import java.io.IOException;

import java.io.InputStreamReader;

import java.util.concurrent.CountDownLatch;

import java.util.concurrent.ExecutorService;

import java.util.concurrent.Executors;

import java.util.logging.ConsoleHandler;

import java.util.logging.FileHandler;

import java.util.logging.Level;

import java.util.logging.Logger;

import java.util.logging.SimpleFormatter;

public class TxtMerge extends Thread {

/**

* 日志

*/

private static Logger logger;

/**

* 日志路径

*/

private static String logPath = "D:\\text\\log.log";

/**

* 日志配置

*/

static {

logger = Logger.getLogger("txtMerge");

FileHandler fh;

try {

fh = new FileHandler(logPath, true);

logger.addHandler(fh);// 日志输出文件

logger.setLevel(Level.ALL);

fh.setFormatter(new SimpleFormatter());// 输出格式

} catch (SecurityException e) {

logger.log(Level.SEVERE, "安全性错误", e);

} catch (IOException e) {

logger.log(Level.SEVERE, "读取文件日志错误", e);

}

}

private static void infoLog(String msg) {

logger.log(Level.INFO, msg);

}

private static void errorLog(String msg, Throwable e) {

logger.log(Level.SEVERE, msg, e);

}

/**

* 待合并文件夹路径

*/

private String path;

/**

* 输出路径(绝对路径)

*/

private String outPath;

/**

* 文件列表

*/

private File[] files;

/**

* 剩余未合并文件数

*/

private Integer fileNum;// 未处理的文件数

/**

* 工作线程总数

*/

private Integer threadNum;

/**

* 对合并文件进行写操作的对象

*/

private FileWriter fileWriter;

/**

*

* @param path

* 待合并文件夹路径

* @param outPath

* 输出路径(绝对路径)

* @param threadNum

* 工作线程总数

*/

public TxtMerge(String path, String outPath, int threadNum) {

this.path = path;

this.outPath = outPath;

this.threadNum = threadNum;

this.files = new File(this.path).listFiles(new FilenameFilter() {

@Override

public boolean accept(File dir, String name) {

if (name.endsWith(".txt"))

return true;

return false;

}

});

this.fileNum = this.files.length;

StringBuilder sBuilder = new StringBuilder(this.fileNum + "个文本文件， at:" + this.path);

for (File f : this.files) {

sBuilder.append("\n");

sBuilder.append(f.getName());

}

infoLog(sBuilder.toString());

}

@Override

public void run() {

if (this.fileNum <= 0) {

infoLog("无文件：" + this.path);

return;

}

CountDownLatch doneSignal = new CountDownLatch(this.threadNum);// 结束信号，用于关闭写操作

CountDownLatch startSignal = new CountDownLatch(1);// 开始执行信号

ExecutorService threadPool = Executors.newCachedThreadPool();

try {

this.fileWriter = new FileWriter(outPath);

} catch (IOException e) {

errorLog("创建输出文件失败", e);

return;

}

for (int i = 0; i < threadNum; i++) {

threadPool.execute(new Worker(startSignal, doneSignal));

}

startSignal.countDown();// 开始

try {

doneSignal.await();// 等待其他线程结束

} catch (InterruptedException e) {

e.printStackTrace();

} finally {

try {

this.fileWriter.close();

} catch (IOException e) {

e.printStackTrace();

}

}

threadPool.shutdown();

infoLog("结束");

}

/**

* 获取一个未处理的文件

*

* @author LiuJie

* @time 2016年8月24日 下午10:43:15

* @return 处理完了返回null

*/

private File getFile() {

if (0 == fileNum) {

return null;

}

File file = null;

synchronized (this.fileNum) {

if (0 < fileNum) {

file = this.files[this.fileNum - 1];

this.fileNum--;

infoLog(Thread.currentThread().getName() + " 操作" + file.getName() + "，剩余：" + fileNum);

}

}

return file;

}

/**

* 工作线程，容器中拿不出文件时结束

*

* @author Liujie

* @time 2016年8月24日 下午11:04:36

*/

private class Worker implements Runnable {

private CountDownLatch startSignal;

private CountDownLatch doneSignal;

public Worker(CountDownLatch startSignal, CountDownLatch doneSignal) {

this.startSignal = startSignal;

this.doneSignal = doneSignal;

}

@Override

public void run() {

infoLog(Thread.currentThread().getName() + " 就绪");

try {

startSignal.await();// 等待开始执行信号的发布

} catch (InterruptedException e1) {

errorLog("等待开始信号异常", e1);

}

infoLog(Thread.currentThread().getName() + " 开始");

FileInputStream fis = null;

InputStreamReader isr = null;

BufferedReader br = null;

while (true) {

File file = getFile();

if (null == file) {

break;

}

try {

fis = new FileInputStream(file);

isr = new InputStreamReader(fis, "UTF-8");

br = new BufferedReader(isr);

String readStr = "";

while ((readStr = br.readLine()) != null) {

synchronized (fileWriter) {

fileWriter.write(readStr + "\r\n");

}

}

} catch (FileNotFoundException e) {

errorLog("找不到指定文件", e);

} catch (IOException e) {

errorLog("读取文件失败", e);

} finally {

try {

br.close();

isr.close();

fis.close();

} catch (IOException e) {

errorLog("关闭异常", e);

}

}

}

doneSignal.countDown();// 告诉“主线程”工作完成

infoLog(Thread.currentThread().getName() + " 结束");

}

}

public static void main(String[] args) throws InterruptedException {

TxtMerge txtMerge = new TxtMerge("D:\\text", "D:\\text\\merge.txt", 5);

txtMerge.start();

}

}