Java与C++通信尝试 Socket通信方式

代码绝大部来自http://www.z6688.com/info/37437-1.htm, 但是在自己调试过程中做了一些补充.

 

Java与C++复合使用还有其他方式(譬如:JNI的), 今天特地尝试了一种Socket的方式:

本代码展示了,java向C++发送一个Employee的Struct结构; 反向的转化碰到了一些问题:

譬如想将C++发送回来的byte[]转化String,但是不能直接用new String(byte[]), java会忽略掉数组中0(这个零在C++中刚好又是字符串结束的标志)

 

Java端代码(window7， jdk1.6):

package tcp.test;

import java.net.*;

/**
 * 与c语言通信(java做client，c/c++做server，传送一个结构)
 * 
 * @author kingfish
 * @version 1.0
 */
public class Employee {
	private byte[] buf = new byte[28]; // 为说明问题，定死大小，事件中可以灵活处理

	/**
	 * 将int转为低字节在前，高字节在后的byte数组
	 */
	private static byte[] tolh(int n) {
		byte[] b = new byte[4];
		b[0] = (byte) (n & 0xff);
		b[1] = (byte) (n >> 8 & 0xff);
		b[2] = (byte) (n >> 16 & 0xff);
		b[3] = (byte) (n >> 24 & 0xff);
		return b;
	}
	/**
	 * 将byte数组转化成String
	 */
	private static String toStr(byte[] valArr,int maxLen) {
		int index = 0;
		while(index < valArr.length && index < maxLen) {
			if(valArr[index] == 0) {
				break;
			}
			index++;
		}
		byte[] temp = new byte[index];
		System.arraycopy(valArr, 0, temp, 0, index);
		return new String(temp);
	}
	
	/**
	 * 将低字节在前转为int，高字节在后的byte数组
	 */
	private static int vtolh(byte[] bArr) {
		int n = 0;
		for(int i=0;i<bArr.length&&i<4;i++){
			int left = i*8;
			n+= (bArr[i] << left);
		}
		return n;
	}
	public String name = "";
	public int id = 0;
	public float salary = 0;
	/**
	 * 将float转为低字节在前，高字节在后的byte数组
	 */
	private static byte[] tolh(float f) {
		return tolh(Float.floatToRawIntBits(f));
	}
	
	private static Employee getEmployee(byte[] bArr) {
		String name = "";
		int id = 0;
		float salary = 0;
		
		byte[] temp = new byte[20];
		name = toStr(bArr,20);
		
		System.arraycopy(bArr, 20, temp, 0, 4);
		id = vtolh(temp);
		
		return new Employee(name, id, salary);
		

	}
	/**
	 * 构造并转换
	 */
	public Employee(String name, int id, float salary) {
		this.name = name;
		this.id = id;
		this.salary = salary;
		
		byte[] temp = name.getBytes();
		System.arraycopy(temp, 0, buf, 0, temp.length);

		temp = tolh(id);
		System.arraycopy(temp, 0, buf, 20, temp.length);

		temp = tolh(salary);
		System.arraycopy(temp, 0, buf, 24, temp.length);
	}
	
	/**
	 * 返回要发送的数组
	 */
	public byte[] getbuf() {
		return buf;
	}

	/**
	 * 发送测试
	 */
	public static void main(String[] args) {
		try {
			int index = 0;
			byte[] receive = new byte[28];
			while(true){
				Socket sock = new Socket("127.0.0.1", 5050);
				System.out.println("send content:  name=kingfish  "+"value="+(1+index));
				sock.getOutputStream().write(new Employee("kingfish"+index, 1+index++, 10.99f + index).getbuf());
				sock.getInputStream().read(receive);
				Employee ee = getEmployee(receive);
				System.out.println("    response:  name="+ee.name+"  "+"value="+ee.id);
				sock.close();
			}
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
} // end 

 

 

C++端代码(环境: window7， visual studio 2008):

 

// SocketTest.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include "stdio.h"   
#include <WINSOCK2.H>  
#pragma comment(lib, "Ws2_32.lib")

struct   UserInfo   {   
  char   UserName[20];   
   int   UserId;   
};   
struct   Employee   {   
  UserInfo   user;   
     float   salary;   
};   
int main(int argc, char* argv[]) {   

			  WSADATA   wsaData;   
				 char   buf[1024];
				  int   nBytes=1024, recvbytes;   
			   SOCKET   Listening;   
			   SOCKET   NewConnection;
		  SOCKADDR_IN   ServerAddr;   
		  SOCKADDR_IN   ClientAddr;   
				  int   ClientAddrLen=sizeof(ClientAddr);   
				  int   Port = 5050;   
				  int   c;
				  WSAStartup(MAKEWORD(2,2),&wsaData);   
				  Listening = socket( AF_INET, SOCK_STREAM, IPPROTO_TCP );   
				  ServerAddr.sin_family = AF_INET;   
				  ServerAddr.sin_addr.s_addr = htonl(INADDR_ANY);   
				  ServerAddr.sin_port = htons(Port);   
				  
				  bind( Listening, (SOCKADDR *)&ServerAddr, sizeof(ServerAddr) );   
				  listen( Listening, 5 );
				  printf( "Wating   accpet....\n" );   

				 
		 while(true) {
				  NewConnection = accept(Listening,(SOCKADDR   *)&ClientAddr, &ClientAddrLen);   
				  printf( "Wating   recv.....\n" );   
				  if( ( recvbytes=recv(NewConnection,buf,nBytes,0) )   ==   SOCKET_ERROR )   
				  {   
					  printf( "\nErrorcode=%d,   Recv   from   client\n", WSAGetLastError() );
					  return   0;   
				  }   
				  Employee   *data   =   new   Employee;   
				  data   =   (Employee   *)&buf;   
				    
				  printf( "Userid:   %d   Username:   %s  Salary:  %f", data->user.UserId, data->user.UserName, data->salary );   
				  data->user.UserId = 007;   
				  strcpy(data->user.UserName, "Test");
				  data->salary = 800;
				    
				  send( NewConnection, buf, recvbytes, 0 );
					 
		  }
		  return   0;

}

 

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评论

1 楼 s_STEFANIE_s 2012-06-07  

谢谢分享，对我很有帮助！