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我试图在java程序中处理从diff的运行得到的数据到GNU grep的一个实例。我设法使用Process对象的outputStream获取diff的输出，但是我目前正在将程序发送给grep的标准输入（通过另一个用Java创建的Process对象）。使用输入运行Grep只会返回状态码1.我做错了什么？将数据写入java中调用的grep程序的InputStream中
下面是我到目前为止的代码：要比较
public class TestDiff {
final static String diffpath = "/usr/bin/";
public static void diffFiles(File leftFile, File rightFile) {
Runtime runtime = Runtime.getRuntime();
File tmp = File.createTempFile("dnc_uemo_", null);
String leftPath = leftFile.getCanonicalPath();
String rightPath = rightFile.getCanonicalPath();
Process proc = runtime.exec(diffpath+"diff -n "+leftPath+" "+rightPath, null);
InputStream inStream = proc.getInputStream();
try {
proc.waitFor();
} catch (InterruptedException ex) {
}
byte[] buf = new byte[256];
OutputStream tmpOutStream = new FileOutputStream(tmp);
int numbytes = 0;
while ((numbytes = inStream.read(buf, 0, 256)) != -1) {
tmpOutStream.write(buf, 0, numbytes);
}
String tmps = new String(buf,"US-ASCII");
inStream.close();
tmpOutStream.close();
FileInputStream tmpInputStream = new FileInputStream(tmp);
Process addProc = runtime.exec(diffpath+"grep \"^a\" -", null);
OutputStream addProcOutStream = addProc.getOutputStream();
numbytes = 0;
while ((numbytes = tmpInputStream.read(buf, 0, 256)) != -1) {
addProcOutStream.write(buf, 0, numbytes);
addProcOutStream.flush();
}
tmpInputStream.close();
addProcOutStream.close();
try {
addProc.waitFor();
} catch (InterruptedException ex) {
}
int exitcode = addProc.exitValue();
System.out.println(exitcode);
inStream = addProc.getInputStream();
InputStreamReader sr = new InputStreamReader(inStream);
BufferedReader br = new BufferedReader(sr);
String line = null;
int numInsertions = 0;
while ((line = br.readLine()) != null) {
String[] p = line.split(" ");
numInsertions += Integer.parseInt(p[1]);
}
br.close();
}
}
两个leftPath和rightPath是指向文件的File对象。