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昨天在实现一个Java程序启动执行C++程序中，遇到了一些问题，先准备把它记录下来（利人利己
）
准备实现的测试功能是这样的：在一个java程序中启动一个C++可执行程序，然后java程序和C++程序相互通信（java端发送消息给C++程序处理，C++处理完成后将返回一个结果消息给java程序。不断往返循环直至输入exit指令结束）。
首先，在一个java程序中启动一个C++可执行程序 使用的是java的Runtime.getRuntime().exec()，Process类exec()官方说明 http://docs.oracle.com/javase/6/docs/api/java/lang/Process.html
【另外，还有一种java的JNI (Java Native Interface)框架可以实现java调用其它编程语言的方法】
*说明*：
使用exec()方式，C++程序的所有标准 io（即 stdin、stdout和 stderr）操作都将通过三个流(getOutputStream()、getInputStream()和 getErrorStream()) 重定向到父进程。
因此，使用上述重定向特性就可以通过标准输入输出实现Java与C++程序间的简单通信，在处理通信I/O时，使用了BufferedReader和BufferedWriter作为通信输入输出的缓冲，方便对消息处理。
关于readLine()，此处有篇博文点击打开链接 http://blog.csdn.net/swingline/article/details/5357581
*注意*：
1. 由于C++端是按行读取消息的，所以在Java端发送消息时要注意每个消息的结尾都必须加上换行符。这就是为何我在writeToCpp.write(wstr+"\n"); 中要+"\n"的原因。（就是因为这个换行符没加导致我调bug费了好长时间，之前一直找不出什么原因导致java端在console中输入消息发送后java程序就跑飞了。。后来发现在eclipse的console中输入字符串回车后该字符串末尾是不带换行符的。。。）
2. 下面的java代码中开辟了一个线程来处理从C++端传送来的消息打印。非常好用！
3. 【引用自点击打开链接】
另外有个问题没解决：
针对Java启动C++程序场景，如何配置使用eclipse和visual studio (2013)使得我能够从eclipse中debug Java程序跟踪到C++程序后能在Visual studio中继续能debug呢？
我查了下，好像可以通过Visual studio的attach to process功能能够实现联调（在VS中依次打开Debug -> Attach to process. 然后找到启动的java进程选中确定【我选的是javaw.exe】），但是我尝试了好久没有成功。（一开始提示找不到PDB文件，我就去vs的TOOLS -> Options -> Debugging -> Symbols勾选了“Microsoft Symbol Servers” ，部分PDB文件就可以加载了，但还有部分PDB文件加载不上。。。打的断点也是显示黄色圆圈带感叹号 【提示信息见下文】）
还请有经验的大侠能帮忙提供下eclipse与VS联调的解决方案，谢谢！！
下面就是实现了双边通信的java和C++源代码
Java端代码片段：
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.util.Scanner;
public class JavaCallCpp {
static BufferedWriter writeToCpp;
static BufferedReader readFromCpp;
public static void main(String[] args) throws IOException {
try {
Process execute = Runtime.getRuntime().exec("D:/WorkSpace/vs/stringstream/Debug/stringstream");
//int exitVal = execute.waitFor();
writeToCpp = new BufferedWriter(new OutputStreamWriter(execute.getOutputStream()));
readFromCpp = new BufferedReader(new InputStreamReader(execute.getInputStream()));
MyThread myThread=new MyThread(readFromCpp);
myThread.start();
/*Write to C++*/
writeToCpp.write("have entered the scentence\n");
writeToCpp.write("aaaaa\n");
writeToCpp.flush();
//writeToCpp.write("quit\n");
//writeToCpp.flush();
/*Read from C++*/
writeToCpp.write("abcd\n");
writeToCpp.flush();
Scanner writer = new Scanner(System.in);
// while(true){
String wstr = null;
while(true){
wstr=writer.next();
if(wstr.equals("exit")){
writer.close();
break;
}
System.out.println(wstr);
writeToCpp.write(wstr+"\n");
writeToCpp.flush();
}
writeToCpp.flush();
System.out.println("out of while.");
/*while((readLine = readFromCpp.readLine()) != null){
System.out.println(readLine);
}*/
// }
//writerString.close();
execute.destroyForcibly();//强制终止
execute.getInputStream().close();
readFromCpp.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}class MyThread extends Thread{
private BufferedReader bfr;
public MyThread(BufferedReader bfr){
this.bfr=bfr;
}
@Override
public void run() {
// TODO Auto-generated method stub
super.run();
String readLine = null;
Boolean _b=true;
try {
while(_b){
readLine=bfr.readLine();
if(readLine==null)
{
_b=false;
}else{
System.out.println(readLine);
}
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
C++端程序片段：
void fun1(){
string cmd;
string line, word;
cout << "enter a scentence, and exit with typing \"quit\""<<endl;
while (getline(cin, line)&& line!="quit")
{
stringstream stream(line);
cout << stream.str() << endl;
while (stream >> word){ cout << word << endl; }
}
while (true){
cout << "please input a command, and exit with typing \"exit\": "<<endl;
getline(std::cin, cmd);
if (0==strcmp(cmd.c_str(),"exit")){ //strcmp返回str1-str2的值
cout << "cmd is exit, exit 0 \n";
exit (0);
}
else if (strcmp(cmd.c_str(), "continue") !=0){
cout << "cmd is not \"continue\" to break\n";
continue;
}
else{
cout << "cmd is continue, break while(true) \n";
break;
}
}
cout << "OK, pass over while(true) \n";
}
/*以下是针对debug问题的（可忽略）*/
eclipse与visual studio联调debug的提示信息：
'javaw.exe' (Win32): Loaded 'C:\Program Files\Java\jdk1.8.0_65\bin\javaw.exe'. Cannot find or open the PDB file. 'javaw.exe' (Win32): Loaded 'C:\Windows\System32\ntdll.dll'. Symbols loaded. 'javaw.exe' (Win32): Loaded 'C:\Windows\System32\kernel32.dll'. Symbols loaded. 'javaw.exe' (Win32): Loaded 'C:\Windows\System32\KernelBase.dll'. Symbols loaded. 'javaw.exe' (Win32): Loaded 'C:\Windows\System32\advapi32.dll'. Symbols loaded. 'javaw.exe' (Win32): Loaded 'C:\Windows\System32\msvcrt.dll'. Symbols loaded. 'javaw.exe' (Win32): Loaded 'C:\Windows\System32\sechost.dll'. Symbols loaded. 'javaw.exe' (Win32): Loaded 'C:\Windows\System32\rpcrt4.dll'. Symbols loaded. 'javaw.exe' (Win32): Loaded 'C:\Windows\System32\user32.dll'. Symbols loaded. 'javaw.exe' (Win32): Loaded 'C:\Windows\System32\gdi32.dll'. Symbols loaded. 'javaw.exe' (Win32): Loaded 'C:\Windows\WinSxS\amd64_microsoft.windows.common-controls_6595b64144ccf1df_6.0.10586.0_none_8c15ae12515e1c22\comctl32.dll'. Symbols loaded. 'javaw.exe' (Win32): Loaded 'C:\Windows\System32\combase.dll'. Cannot find or open the PDB file. 'javaw.exe' (Win32): Loaded 'C:\Windows\System32\bcryptprimitives.dll'. Cannot find or open the PDB file. 'javaw.exe' (Win32): Loaded 'C:\Windows\System32\imm32.dll'. Cannot find or open the PDB file. 'javaw.exe' (Win32): Loaded 'C:\Program Files\Java\jdk1.8.0_65\jre\bin\msvcr100.dll'. Symbols loaded. 'javaw.exe' (Win32): Loaded 'C:\Program Files\Java\jdk1.8.0_65\jre\bin\server\jvm.dll'. Cannot find or open the PDB file. 'javaw.exe' (Win32): Loaded 'C:\Windows\System32\psapi.dll'. Symbols loaded. 'javaw.exe' (Win32): Loaded 'C:\Windows\System32\wsock32.dll'. Symbols loaded. 'javaw.exe' (Win32): Loaded 'C:\Windows\System32\ws2_32.dll'. Symbols loaded. 'javaw.exe' (Win32): Loaded 'C:\Windows\System32\version.dll'. Symbols loaded. 'javaw.exe' (Win32): Loaded 'C:\Windows\System32\winmm.dll'. Symbols loaded. 'javaw.exe' (Win32): Loaded 'C:\Windows\System32\winmmbase.dll'. Symbols loaded. 'javaw.exe' (Win32): Loaded 'C:\Windows\System32\cfgmgr32.dll'. Symbols loaded. 'javaw.exe' (Win32): Loaded 'C:\Program Files\Java\jdk1.8.0_65\jre\bin\verify.dll'. Cannot find or open the PDB file. 'javaw.exe' (Win32): Loaded 'C:\Program Files\Java\jdk1.8.0_65\jre\bin\java.dll'. Cannot find or open the PDB file. 'javaw.exe' (Win32): Loaded 'C:\Program Files\Java\jdk1.8.0_65\jre\bin\jdwp.dll'. Cannot find or open the PDB file. 'javaw.exe' (Win32): Loaded 'C:\Program Files\Java\jdk1.8.0_65\jre\bin\npt.dll'. Cannot find or open the PDB file. 'javaw.exe' (Win32): Loaded 'C:\Program Files\Java\jdk1.8.0_65\jre\bin\zip.dll'. Cannot find or open the PDB file. 'javaw.exe' (Win32): Loaded 'C:\Windows\System32\shell32.dll'. Symbols loaded. 'javaw.exe' (Win32): Loaded 'C:\Windows\System32\windows.storage.dll'. Symbols loaded. 'javaw.exe' (Win32): Loaded 'C:\Windows\System32\shlwapi.dll'. Symbols loaded. 'javaw.exe' (Win32): Loaded 'C:\Windows\System32\kernel.appcore.dll'. Symbols loaded. 'javaw.exe' (Win32): Loaded 'C:\Windows\System32\SHCore.dll'. Symbols loaded. 'javaw.exe' (Win32): Loaded 'C:\Windows\System32\powrprof.dll'. Cannot find or open the PDB file. 'javaw.exe' (Win32): Loaded 'C:\Windows\System32\profapi.dll'. Cannot find or open the PDB file. 'javaw.exe' (Win32): Loaded 'C:\Program Files\Java\jdk1.8.0_65\jre\bin\dt_socket.dll'. Cannot find or open the PDB file. 'javaw.exe' (Win32): Loaded 'C:\Windows\System32\NapiNSP.dll'. Symbols loaded. 'javaw.exe' (Win32): Loaded 'C:\Windows\System32\pnrpnsp.dll'. Symbols loaded. 'javaw.exe' (Win32): Loaded 'C:\Windows\System32\nlaapi.dll'. Symbols loaded. 'javaw.exe' (Win32): Loaded 'C:\Windows\System32\mswsock.dll'. Symbols loaded. 'javaw.exe' (Win32): Loaded 'C:\Windows\System32\dnsapi.dll'. Symbols loaded. 'javaw.exe' (Win32): Loaded 'C:\Windows\System32\nsi.dll'. Symbols loaded. 'javaw.exe' (Win32): Loaded 'C:\Windows\System32\winrnr.dll'. Symbols loaded. 'javaw.exe' (Win32): Loaded 'C:\Windows\System32\wshbth.dll'. Symbols loaded. 'javaw.exe' (Win32): Loaded 'C:\Windows\System32\FWPUCLNT.DLL'. Cannot find or open the PDB file. 'javaw.exe' (Win32): Loaded 'C:\Windows\System32\bcrypt.dll'. Cannot find or open the PDB file. 'javaw.exe' (Win32): Loaded 'C:\Windows\System32\rasadhlp.dll'. Cannot find or open the PDB file.
BufferedWriter.write()与BufferedReader.readLine() (附带Java中的Runtime exec)
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原文地址：http://blog.csdn.net/haifeng_gu/article/details/51916187
