android的NDK和java进行本地socket通信

关于Android应用与Framework的socket通信，相信关心这个问题的朋友们已经看过《android使用socket使底层和framework通信》这篇文章，美中不足的是作者只贴出一些关键的代码片段而并没有放出源码。我这里还是以一个能实际运行的例子为基础来讲，这样也方便大家学习。

首先看一下效果，如下图。我填写姓名"Potter"，选择性别"Mr"然后点击发送，底层socket收到消息后将消息直接返回给我，我将返回的结果（Mr.Potter）直接显示在Result。

编写socket服务端代码，生成可执行脚本htfsk。

#define SOCKET_NAME "htfsk"

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <sys/wait.h>
#include <sys/un.h>
#include <cutils/sockets.h>
#include <utils/Log.h>
#include <android/log.h>

int main(){
    char log[200]; 

    int connect_number = 6;
    int fdListen = -1, new_fd = -1;
    int ret;
    struct sockaddr_un peeraddr;
    socklen_t socklen = sizeof (peeraddr);
    int numbytes ;
    char buff[256];
    //这一步很关键，就是获取init.rc中配置的名为 "htfsk" 的socket
    fdListen = android_get_control_socket(SOCKET_NAME);
    if (fdListen < 0) {
	sprintf(log,"Failed to get socket '" SOCKET_NAME "' errno:%d", errno);
	__android_log_write(ANDROID_LOG_DEBUG,"FTM_JNI",log);
	exit(-1);
    }
    //开始监听
    ret = listen(fdListen, connect_number);    

    sprintf(log,"Listen result %d",ret);
    __android_log_write(ANDROID_LOG_DEBUG,"FTM_JNI",log); 

    if (ret < 0) {
        perror("listen");
        exit(-1);
    }
    //等待Socket客户端发启连接请求
    new_fd = accept(fdListen, (struct sockaddr *) &peeraddr, &socklen);
    sprintf(log,"Accept_fd %d",new_fd);
    __android_log_write(ANDROID_LOG_DEBUG,"FTM_JNI",log);
    if (new_fd < 0 ) {
        sprintf(log,"%d",errno);
        __android_log_write(ANDROID_LOG_DEBUG,"FTM_JNI",log);
        perror("accept error");
        exit(-1);
    }

    while(1){
	//循环等待Socket客户端发来消息
	__android_log_write(ANDROID_LOG_DEBUG,"FTM_JNI","Waiting for receive");
	if((numbytes = recv(new_fd,buff,sizeof(buff),0))==-1){
        sprintf(log,"%d",errno);
        __android_log_write(ANDROID_LOG_DEBUG,"FTM_JNI",log);
		perror("recv");
		continue;
	}
	//发送消息回执给Socket客户端
	if(send(new_fd,buff,strlen(buff),0)==-1)
	{
		perror("send");
		close(new_fd);
		exit(0);
	}
    }

    close(new_fd);
    close(fdListen);
    return 0;
}

3、编写客户端java代码。核心代码如下：

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;

import android.net.LocalSocket;
import android.net.LocalSocketAddress;
import android.util.Log;

/**
 * Socket客户端
 *
 * @author lai_zs
 * @date：2012-3-17 下午12:15:09
 */
public class SocketClient {
	private final String SOCKET_NAME = "htfsk";
	private LocalSocket client;
	private LocalSocketAddress address;
	private boolean isConnected = false;
	private int connetTime = 1;

	public SocketClient() {
		client = new LocalSocket();
		address = new LocalSocketAddress(SOCKET_NAME, LocalSocketAddress.Namespace.RESERVED);
		new ConnectSocketThread().start();
	}

	/**
	 * 发送消息
	 * @param msg
	 * @return 返回Socket服务端的消息回执
	 */
	public String sendMsg(String msg) {
		if (!isConnected) {
			return "Connect fail";
		}
		try {
			BufferedReader in = new BufferedReader(new InputStreamReader(client.getInputStream()));
			PrintWriter out = new PrintWriter(client.getOutputStream());
			out.println(msg);
			out.flush();
			return in.readLine();
		} catch (IOException e) {
			e.printStackTrace();
		}
		return "Nothing return";
	}

	/**
	 * 异步连接Socket,如果连接不上会尝试重复连接十次
	 *
	 * @author Administrator
	 *
	 */
	private class ConnectSocketThread extends Thread {
		@Override
		public void run() {
			while (!isConnected && connetTime <= 10) {
				try {
					sleep(1000);
					Log.i("SocketClient","Try to connect socket;ConnectTime:"+connetTime);
					client.connect(address);
					isConnected = true;
				} catch (Exception e) {
					connetTime++;
					isConnected = false;
					Log.i("SocketClient","Connect fail");
				}
			}
		}
	}

	/**
	 * 关闭Socket
	 */
	public void closeSocket() {
		try {
			client.close();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

}