跨进程同步锁的实现方法：

1. C++ named mutex

2. 文件是全系统通用的，可以通过文件锁来实现变相的跨进程锁

一个 java 例子：

ProgramA

import java.io.BufferedReader;
import java.io.File;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.RandomAccessFile;
import java.nio.ByteBuffer;
import java.nio.MappedByteBuffer;
import java.nio.channels.FileChannel;
import java.nio.channels.FileLock;

public class ProgramA {

    public static void main(String[] args) throws IOException {
        
        RandomAccessFile randomAccessFile = new RandomAccessFile("884e94ae-e524-4c73-9200-3df9bec9f6af", "rw");
        FileChannel fileChannel = randomAccessFile.getChannel();
        FileLock fileLock = null;
        
        try
        {
            fileLock = fileChannel.lock();
            
            System.out.println("A已获取锁");
            
            BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
            reader.readLine();
        }
        finally
        {
            fileLock.release();
            System.out.println("A已释放锁");
        }
    }
}

 

ProgramB：

import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.RandomAccessFile;
import java.nio.ByteBuffer;
import java.nio.MappedByteBuffer;
import java.nio.channels.FileChannel;
import java.nio.channels.FileLock;

public class ProgramB {

    public static void main(String[] args) throws IOException {
        RandomAccessFile randomAccessFile = new RandomAccessFile("884e94ae-e524-4c73-9200-3df9bec9f6af", "rw");
        FileChannel fileChannel = randomAccessFile.getChannel();
        FileLock fileLock = null;
        
        try
        {
            System.out.println("B正在获取锁");
            fileLock = fileChannel.lock();
            System.out.println("B已获取锁");
            
            BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
            reader.readLine();
        }
        finally
        {
            fileLock.release();
            System.out.println("B已释放锁");
        }
    }

}

 

其实还可以这样实现：

import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.nio.channels.FileChannel;
import java.nio.channels.FileLock;

public class CrossProcessLocker implements AutoCloseable {

    private String id = null;
    private FileLock fileLock = null;
    
    @SuppressWarnings("resource")
    public CrossProcessLocker(String id) throws IOException {
        this.id = id;
        RandomAccessFile randomAccessFile = new RandomAccessFile(id, "rw");
        FileChannel fileChannel = randomAccessFile.getChannel();
        fileLock = fileChannel.lock();
    }
    
    @Override
    public void close() throws Exception {
        fileLock.release();
    }
    
}

import java.io.BufferedReader;
import java.io.File;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.RandomAccessFile;
import java.nio.ByteBuffer;
import java.nio.MappedByteBuffer;
import java.nio.channels.FileChannel;
import java.nio.channels.FileLock;

public class ProgramA {

    public static void main(String[] args) throws Exception {
        
        System.out.println("A正在获取锁");
        try(CrossProcessLocker cpl = new CrossProcessLocker("884e94ae-e524-4c73-9200-3df9bec9f6af"))
        {
            System.out.println("A已获取锁");
            BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
            reader.readLine();
        }
        
        System.out.println("A已释放锁");
    }
}

import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.RandomAccessFile;
import java.nio.ByteBuffer;
import java.nio.MappedByteBuffer;
import java.nio.channels.FileChannel;
import java.nio.channels.FileLock;
import java.util.Timer;
import java.util.TimerTask;

public class ProgramB {

    public static void main(String[] args) throws Exception {
        
        System.out.println("B正在获取锁");
        try(CrossProcessLocker cpl = new CrossProcessLocker("884e94ae-e524-4c73-9200-3df9bec9f6af"))
        {
            System.out.println("B已获取锁");
            BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
            reader.readLine();
        }
        
        System.out.println("B已释放锁");
    }

}