android native c java进行本地socket通信

http://blog.csdn.net/weidawei0609/article/details/7327626

android native c  java进行本地socket通信

方式一：java做服务器端，native做client端
1. 建立java应用程序，建立Server 类
/*
 * Copyright (C) 2009 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.example.hellojni;

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.net.LocalServerSocket;
import android.net.LocalSocket;


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


public class HelloJni extends Activity
{
    public static final String SOCKET_NAME = "server_test";
    private static final String TAG = "SocketService";
    private LocalServerSocket mServerSocket = null;
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);

	Log.v(TAG, "onCreate");
        try {
            mServerSocket = new LocalServerSocket(SOCKET_NAME);
        } catch (IOException e) {
            Log.v(TAG, "in onCreate, making server socket: " + e);
            return;
        }

        Thread t = new Thread() {
                @Override public void run() {
                    LocalSocket socket = null;
                    while (true) {
                        try {
                            Log.v(TAG, "Waiting for connection...");
                            socket = mServerSocket.accept();
                            Log.v(TAG, ".....Got socket: " + socket);
                            if (socket != null) {
                                startEchoThread(socket);
                            } else {
                                return;  // socket shutdown?
                            }
                        } catch (IOException e) {
                            Log.v(TAG, "in accept: " + e);
                        }
                    }
                }
            };
        t.start();


    }

private void startEchoThread(final LocalSocket socket) {
        Thread t = new Thread() {
                @Override public void run() {
                    try {
                        InputStream is = socket.getInputStream();
                        OutputStream os = socket.getOutputStream();
                        InputStreamReader isr = new InputStreamReader(is);
                        while (true) {
                            char[] data = new char[128];

                            int ret = isr.read(data);
                            for(int i=0;i<ret;i++){
                                Log.d(TAG, "data["+i+"]="+data[i]);
                            }
                            byte[] values = TypeUtils.float2Byte(-1234567.122f);
                            float fd = -1234567.122f;
                            Log.d(TAG, " fd="+fd);
                            for(int i=0;i<values.length;i++){
                                Log.d(TAG, "values["+i+"]="+values[i]);
                            }
                            os.write(values);
                            os.flush();
                           Log.v(TAG, "after write: ");
                        }
                    } catch (IOException e) {
                        Log.v(TAG, "in echo thread loop: " + e.getMessage());
                    }
                }
            };
        t.start();
    }

}









2.将float转换成byte[]数组的工具类

import java.nio.ByteBuffer;
import java.nio.FloatBuffer;

public class TypeUtils {

    public static byte[] floatToByte(float v) {
        ByteBuffer bb = ByteBuffer.allocate(4);
        byte[] ret = new byte[4];
        FloatBuffer fb = bb.asFloatBuffer();
        fb.put(v);
        bb.get(ret);
        return ret;
    }

    public static byte[] float2Byte(float f) {
        byte[] b = new byte[4];
        int l = Float.floatToIntBits(f);
        for (int i = 0; i < b.length; i++) {
            b[i] = new Integer(l).byteValue();
            l = l >> 8;
        }
        return b;
    }

    public static byte[] doubleToByte(double d) {
        byte[] b = new byte[8];
        long l = Double.doubleToLongBits(d);
        for (int i = 0; i < b.length; i++) {
            b[i] = new Long(l).byteValue();
            l = l >> 8;
        }
        return b;
    }

    public static float byteToFloat(byte[] v) {
        ByteBuffer bb = ByteBuffer.wrap(v);
        FloatBuffer fb = bb.asFloatBuffer();
        return fb.get();
    }

    public static float byte2Float(byte[] b) {
        int l = 0;
        l = b[0];
        l &= 0xff;
        l |= ((int) b[1] << 8);
        l &= 0xffff;
        l |= ((int) b[2] << 16);
        l &= 0xffffff;
        l |= ((int) b[3] << 24);
        l &= 0xffffffffl;
        return Float.intBitsToFloat(l);
    }
}

3.在 native中建立client


#include 
   
    

static union FloatValue{
char val[4];
float f;
} mf_t;
static __inline__ int
qemud_fd_write(int  fd, const void*  buff, int  len)
{
    int  len2;
    do {
        len2 = write(fd, buff, len);
    } while (len2 < 0 && errno == EINTR);
    return len2;
}

static __inline__ int
qemud_fd_read(int  fd, void*  buff, int  len)
{
    int  len2;
    do {
        len2 = read(fd, buff, len);
    } while (len2 < 0 && errno == EINTR);
    return len2;
}




int main(int argc, char **argv)
{
    int  fd;
    char answer[200];
    char name[5]= "test!";
    int namelen = 5;
    /* connect to qemud control socket */
    fd = socket_local_client( "server_test",
                              ANDROID_SOCKET_NAMESPACE_ABSTRACT,
                              SOCK_STREAM );
    if (fd < 0) {
        printf("no qemud control socket: %s \n", strerror(errno));
        return -1;
    }

    /* send service name to connect */
    if (qemud_fd_write(fd, name, namelen) != namelen) {
        printf("can't send service name to qemud: %s \n",
           strerror(errno));
        close(fd);
        return -1;
    }
  printf(".... before  qemud_fd_read \n");
    /* read answer from daemon */
    int res =qemud_fd_read(fd, answer, 200);

    printf(" .....after  qemud_fd_read ");
    if (res) {
        printf("connect  to service through qemud res =%d  answer0 =%d ,answer1 =%d answer2 =%d ,answer3 =%d \n",res,answer[0],answer[1],answer[2],answer[3]);
     mf_t.val[0] = answer[0];
     mf_t.val[1] = answer[1];
     mf_t.val[2] = answer[2];
     mf_t.val[3] = answer[3];
      printf(" .....after  convert f=%f \n",mf_t.f);
        close(fd);
        return -1;
    }

    return 0;
}
   

这样就实现了java和native进行通信的目的了，而且是本地socket哟。