如何在Java程序中编译和运行

您的代码可能失败的地方有很多，例如，由于某种原因它可能无法编译；

java

java

src/HelloWorld

我相信您的命令应该看起来更像

java -cp ./src HelloWorld

src

您确实需要尽一切努力来诊断潜在的问题，例如

DiagnosticCollector

JavaCompiler

InputStream

ErrorStream

根据您

HelloWorld.java

import java.io.File;import java.io.IOException;import java.io.InputStream;import java.util.ArrayList;import java.util.Arrays;import java.util.List;import java.util.logging.Level;import java.util.logging.Logger;import javax.tools.Diagnostic;import javax.tools.DiagnosticCollector;import javax.tools.JavaCompiler;import javax.tools.JavaFileObject;import javax.tools.StandardJavaFileManager;import javax.tools.ToolProvider;public class TestCompile {    public static void main(String[] args) {        StringBuilder sb = new StringBuilder(64);        try { DiagnosticCollector<JavaFileObject> diagnostics = new DiagnosticCollector<>(); JavaCompiler compiler = ToolProvider.getSystemJavaCompiler(); try (StandardJavaFileManager fileManager = compiler.getStandardFileManager(diagnostics, null, null)) {     // >>>> Compiler Stage     // This sets up the class path that the compiler will use.     // I've added the .jar file that contains the DoStuff interface within in it...     List<String> optionList = new ArrayList<>();     optionList.add("-classpath");     optionList.add(System.getProperty("java.class.path"));     Iterable<? extends JavaFileObject> compilationUnit          = fileManager.getJavaFileObjectsFromFiles(Arrays.asList(new File("src/HelloWorld.java")));     JavaCompiler.CompilationTask task = compiler.getTask(          null,          fileManager,          diagnostics,          optionList,          null,          compilationUnit);     if (task.call()) {         // <<<< Compiler Stage         // >>>> Run stage...         ProcessBuilder pb = new ProcessBuilder("java", "-cp", "./src", "HelloWorld");         pb.redirectError();         Process p = pb.start();         InputStreamConsumer.consume(p.getInputStream());         p.waitFor();         // <<<< Run Stage     } else {         for (Diagnostic<? extends JavaFileObject> diagnostic : diagnostics.getDiagnostics()) {  System.out.format("Error on line %d in %s%n",       diagnostic.getLineNumber(),       diagnostic.getSource().toUri());         }     } } catch (InterruptedException ex) {     Logger.getLogger(TestCompile.class.getName()).log(Level.SEVERE, null, ex); }        } catch (IOException exp) { exp.printStackTrace();        }    }    public static class InputStreamConsumer implements Runnable {        private InputStream is;        public InputStreamConsumer(InputStream is) { this.is = is;        }        public InputStream getInputStream() { return is;        }        public static void consume(InputStream is) { InputStreamConsumer consumer = new InputStreamConsumer(is); Thread t = new Thread(consumer); t.start();        }        @Override        public void run() { InputStream is = getInputStream(); int in = -1; try {     while ((in = is.read()) != -1) {         System.out.print((char)in);     } } catch (IOException exp) {     exp.printStackTrace(); }        }    }}

作为使用的替代方法

ProcessBuilder pb = new ProcessBuilder("java", "-cp", "./src","HelloWorld");

ProcessBuilder pb = new ProcessBuilder("java", "HelloWorld");pb.directory(new File("src"));pb.redirectError();Process p = pb.start();

这将

java

src