Launch JVM process from a Java application use Runtime.exec?

问题:

I want to be able to launch a Java server process from an existing java application and monitor the stdoutput and stderror and redirect that output to a file. Is the best approach to use 'Runtime.exec' and treat the app like any other OS process or is there something more suited for new JVMs.

This is on Java 1.5

回答1:

Instead of Runtime, you should probably use ProcessBuilder, though I don't know if something else is even more appropriate in your case (running a Java process in particular).

回答2:

I know I am late in this thread, but in case someone needs it, in my experience, it is easier to use ANT to launch a Java application. This has the benefit of being platform independent. Here is a sample class that does that:

package com.trilliantnetworks.scheduler.quartz.test;  import java.io.File; import java.io.PrintStream; import org.apache.tools.ant.BuildException; import org.apache.tools.ant.DefaultLogger; import org.apache.tools.ant.DemuxOutputStream; import org.apache.tools.ant.Project; import org.apache.tools.ant.taskdefs.Echo; import org.apache.tools.ant.taskdefs.Java; import org.apache.tools.ant.types.Path;  public class MyLaunchTest {  public static void main(String[] args) {      Project project = new Project();     project.setBaseDir(new File(System.getProperty("user.dir")));     project.init();     DefaultLogger logger = new DefaultLogger();     project.addBuildListener(logger);     logger.setOutputPrintStream(System.out);     logger.setErrorPrintStream(System.err);     logger.setMessageOutputLevel(Project.MSG_INFO);     System.setOut(new PrintStream(new DemuxOutputStream(project, false)));     System.setErr(new PrintStream(new DemuxOutputStream(project, true)));     project.fireBuildStarted();      System.out.println("running");     Throwable caught = null;     try {         Echo echo = new Echo();         echo.setTaskName("Echo");         echo.setProject(project);         echo.init();         echo.setMessage("Launching Some Class");         echo.execute();          Java javaTask = new Java();         javaTask.setTaskName("runjava");         javaTask.setProject(project);         javaTask.setFork(true);         javaTask.setFailonerror(true);         javaTask.setClassname(MyClassToLaunch.class.getName());         Path path = new Path(project, new File(System.getProperty("user.dir") + "/classes").getAbsolutePath());         javaTask.setClasspath(path);         javaTask.init();         int ret = javaTask.executeJava();         System.out.println("java task return code: " + ret);      } catch (BuildException e) {         caught = e;     }     project.log("finished");     project.fireBuildFinished(caught); } } 

回答3:

If you do decide to use Runtime, read "When Runtime.exec Won't..."

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