使用java的交互式命令Runtime.getRunTime.exec（）

Question

如何使用Runtime.getRunTime.exec（）發送和接收多個輸入。

例如，如果我想運行諸如openSSL之類的東西來生成csr，它會詢問諸如狀態，城市，常用名等內容。

Process p = Runtime.getRuntime().exec(cmd); 
OutputStream out = p.getOutputStream(); 
//print stuff p.getInputStream(); 
//Now i want to send some inputs 
out.write("test".getBytes()); 
//flush and close??? don't know what to do here 
//print what ever is returned 
//Now i want to send some more inputs 
out.write("test2".getBytes()); 
//print what ever is returned.. and so on until this is complete 

爲什麼不使用p.getInputStream（）來讀取你所需要的使用out.write而 發送（）相應地發送數據。

Process p = Runtime.getRuntime().exec(cmd); 
OutputStream out = p.getOutputStream(); 
//print stuff p.getInputStream(); 
out.write("test".getBytes()); 
out.close(); //if i don't close, it will just sit there 
//print stuff p.getInputStream(); 
out.write("test".getBytes()); // I can no longer write at this point, maybe because the outputstream was closed? 

Answer 1

爲什麼不使用p.getInputStream().read()看你需要什麼，而使用out.write()相應地發送數據要發送。

這裏是取自一個例子：http://www.rgagnon.com/javadetails/java-0014.html

String line; 
OutputStream stdin = null; 
InputStream stderr = null; 
InputStream stdout = null; 

    // launch EXE and grab stdin/stdout and stderr 
    Process process = Runtime.getRuntime().exec ("/folder/exec.exe"); 
    stdin = process.getOutputStream(); 
    stderr = process.getErrorStream(); 
    stdout = process.getInputStream(); 

    // "write" the parms into stdin 
    line = "param1" + "\n"; 
    stdin.write(line.getBytes()); 
    stdin.flush(); 

    line = "param2" + "\n"; 
    stdin.write(line.getBytes()); 
    stdin.flush(); 

    line = "param3" + "\n"; 
    stdin.write(line.getBytes()); 
    stdin.flush(); 

    stdin.close(); 

    // clean up if any output in stdout 
    BufferedReader brCleanUp = 
    new BufferedReader (new InputStreamReader (stdout)); 
    while ((line = brCleanUp.readLine()) != null) { 
    //System.out.println ("[Stdout] " + line); 
    } 
    brCleanUp.close(); 

    // clean up if any output in stderr 
    brCleanUp = 
    new BufferedReader (new InputStreamReader (stderr)); 
    while ((line = brCleanUp.readLine()) != null) { 
    //System.out.println ("[Stderr] " + line); 
    } 
    brCleanUp.close();