异常捕获！

[HACKOR-INC]

Runtime rt = Runtime.getRuntime();
rt.exec("java a");
请教怎么能捕获类a产生的异常？！

[oldcat0076]

你在类a里面自己捕获或者在类a中抛出异常，在外面捕获，如：
try{
Runtime rt = Runtime.getRuntime();
rt.exec("java a");
}
catch(Exception e){
}

[skyyoung]

你想在JAVA里执行另外的JAVA程序吗。给个程序你看看。
import java.io.*;
import java.util.*;
import java.lang.reflect.*;

public class MakeTodayClass {
Date today = new Date();
String todayMillis = Long.toString(today.getTime());
String todayClass = "z_" + todayMillis;
String todaySource = todayClass + ".java";

public static void main (String args[]){
MakeTodayClass mtc = new MakeTodayClass();
mtc.createIt();
if (mtc.compileIt()) {
System.out.println("Running " + mtc.todayClass + ":\n\n");
mtc.runIt();
}
else
System.out.println(mtc.todaySource + " is bad.");
}

public void createIt() {
try {
FileWriter aWriter = new FileWriter(todaySource, true);
//aWriter.write("package com;");
aWriter.write("public class "+ todayClass + "{");
aWriter.write(" public void doit() {");
aWriter.write(" System.out.println(\""+todayMillis+"\");");
aWriter.write(" }}\n");
aWriter.flush();
aWriter.close();
}
catch(Exception e){
e.printStackTrace();
}
}

public boolean compileIt() {
String [] source = {"-d","d:/",new String(todaySource) };
ByteArrayOutputStream baos= new ByteArrayOutputStream();

//new sun.tools.javac.Main(baos,source[0]).compile(source);
// if using JDK >= 1.3 then use
System.out.println(com.sun.tools.javac.Main.compile(source));
System.out.println("================"+new String(baos.toByteArray()));
return (baos.toString().indexOf("error")==-1);
}

public void runIt() {
try {
Class params[] = {};
Object paramsObj[] = {};
Class thisClass = Class.forName(todayClass);
Object iClass = thisClass.newInstance();
Method thisMethod = thisClass.getDeclaredMethod("doit", params);
thisMethod.invoke(iClass, paramsObj);
}
catch (Exception e) {
e.printStackTrace();
}
}
}