如何用java代码运行外部程序？
package com.test;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;

public class EXERunner {

	public void runExe(String exePath) {
		try {
			Process process = Runtime.getRuntime().exec(exePath);
			// 注：process进程的输出流 相对于本进程就是输入流
			Thread errorHandler = new Thread(new ErrorIOHandler(process.getErrorStream()));
			Thread normalHandler = new Thread(new NormalIOHandler(process.getInputStream()));
			Thread cmdHandler = new Thread(new CmdIOHandler(process.getOutputStream()));
			errorHandler.start();
			normalHandler.start();
			cmdHandler.start();
			process.waitFor(); // 等待process进程的输出流都被处理
			int exitValue = process.exitValue();
			if (exitValue == 0) {
				System.out.println("进程正常退出");
			} else {
				System.out.println("进程异常退出");
			}
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

	public static void main(String[] args) {
		new EXERunner().runExe("C:\\Windows\\System32\\ipconfig.exe");
	}
}

// 处理外部程序的错误输出流
class ErrorIOHandler implements Runnable {

	private InputStream error;

	public ErrorIOHandler(InputStream error) {
		this.error = error;
	}

	@Override
	public void run() {
		BufferedReader br = new BufferedReader(new InputStreamReader(error));
		String line = "";
		try {
			while ((line = br.readLine()) != null) {
				System.out.println(line);
			}
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

}

// 处理外部程序的正常输出流
class NormalIOHandler implements Runnable {

	private InputStream normal;

	public NormalIOHandler(InputStream normal) {
		this.normal = normal;
	}

	@Override
	public void run() {
		BufferedReader br = new BufferedReader(new InputStreamReader(normal));
		String line = "";
		try {
			while ((line = br.readLine()) != null) {
				System.out.println(line);
			}
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

}

// 给外部程序发送命令
class CmdIOHandler implements Runnable {

	private OutputStream out;

	public CmdIOHandler(OutputStream out) {
		this.out = out;
	}

	@Override
	public void run() {
		try {
			String line = "";
			BufferedReader br = new BufferedReader(new InputStreamReader(System.in));//控制台读取流
			while (true) {
				line = br.readLine();//从控制台读取一行
				if (line.equals("")) {
					break;
				} else {
					out.write((line + "\r\n").getBytes());//发送命令给外部程序
				}
				out.flush();
			}
			br.close();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}
}

如何用java代码运行外部程序？package com.test;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
public class EXERunner {
public void runExe(String exePath) {
try {
Process process = Runtime.getRuntime().exec(exePath);
// 注：process进程的输出流 相对于本进程就是输入流
Thread errorHandler = new Thread(new ErrorIOHandler(process.getErrorStream()));
Thread normalHandler = new Thread(new NormalIOHandler(process.getInputStream()));
Thread cmdHandler = new Thread(new CmdIOHandler(process.getOutputStream()));
errorHandler.start();
normalHandler.start();
cmdHandler.start();
process.waitFor(); // 等待process进程的输出流都被处理
int exitValue = process.exitValue();
if (exitValue == 0) {
System.out.println("进程正常退出");
} else {
System.out.println("进程异常退出");
}
} catch (Exception e) {
e.printStackTrace();
}
}
public static void main(String[] args) {
new EXERunner().runExe("C:\\Windows\\System32\\ipconfig.exe");
}
}
// 处理外部程序的错误输出流
class ErrorIOHandler implements Runnable {
private InputStream error;
public ErrorIOHandler(InputStream error) {
this.error = error;
}
@Override
public void run() {
BufferedReader br = new BufferedReader(new InputStreamReader(error));
String line = "";
try {
while ((line = br.readLine()) != null) {
System.out.println(line);
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
// 处理外部程序的正常输出流
class NormalIOHandler implements Runnable {
private InputStream normal;
public NormalIOHandler(InputStream normal) {
this.normal = normal;
}
@Override
public void run() {
BufferedReader br = new BufferedReader(new InputStreamReader(normal));
String line = "";
try {
while ((line = br.readLine()) != null) {
System.out.println(line);
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
// 给外部程序发送命令
class CmdIOHandler implements Runnable {
private OutputStream out;
public CmdIOHandler(OutputStream out) {
this.out = out;
}
@Override
public void run() {
try {
String line = "";
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));//控制台读取流
while (true) {
line = br.readLine();//从控制台读取一行
if (line.equals("")) {
break;
} else {
out.write((line + "\r\n").getBytes());//发送命令给外部程序
}
out.flush();
}
br.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}

    

            
可执行类
Runtime.getRuntime().exec("C:\\Users\\xu\\Desktop\\stop.exe");

链接类
 ProcessBuilder pb = new ProcessBuilder("cmd","/c","C:\\Users\\xu\\Desktop\\stop.cmd.lnk"); 
  Process process = pb.start(); 


          
  

Java运行外部程序问题解决


1、现象：问题描述

   关于java通过Runtime.getRuntime.exec()运行外部命令抛异常的解决方法在java程序中频繁调用Runtime.getRuntime.exec("command")来运行一个外部命令。发现运行一段时间以后会抛出异常： IOException：too many files open 检查程序，凡是使用的流都关闭了，还是抛异常。

2、关键过程：根本原因分析

   后来上网查了一把，发现在Solaris下使用： Process = Runtime.exec("command") 运行一个外部程序后，Process对象的三个流(InputStream,OutputStream,ErrorStream) 即使你不使用，也要人为地get出来后显式的调用close()关闭。否则相关的文件句柄不会释放。我在使用的时候只用到了OutputStream，也就只关闭了OutputStream, 剩下的两个流我没有用到，就没有获得，当然也没有关闭，于是积累下来，过一段时间就打开了过多的文件句柄，抛异常了。

3、结论：解决方案及效果加入以下语句后解决问题：

process.getInputStream().close();

process.getOutputStream().close();

process.getErrorStream().close();

4、经验总结：预防措施和规范建议

Process对象的三个流(InputStream,OutputStream,ErrorStream) 都需要关闭。