動態生成編譯運行java類

  本代碼並非原創,是在我以前的學習筆記裏面翻閱出來的,是csdn裏面一位叫路人甲的朋友在論壇裏面的回覆,也許在這裏發出來會幫助到很多朋友.其實十分簡單就不加註釋了,一共就3步,生成java文件,編譯java文件,運行java類,

 

 

 package com.syj; import java.io.File; import java.io.FileWriter; import java.lang.reflect.Method; public class CreateClass { private static String CLASS_NAME = "CreateClassTest"; private static String CLASS_FILE = CLASS_NAME + ".java"; public static void main(String args[]) { CreateClass mtc = new CreateClass(); mtc.createClass(); System.out.println("javac " + CLASS_FILE); mtc.compileClass(); System.out.println("java " + CLASS_NAME); mtc.runClass(); } public void createClass() { try { new File(CLASS_FILE).delete(); FileWriter aWriter = new FileWriter(CLASS_FILE, true); aWriter.write("public class " + CLASS_NAME + "{"); aWriter.write("public void println() {"); aWriter.write("System.out.println("=" + CLASS_NAME + "=");"); aWriter.write("}}"); aWriter.flush(); aWriter.close(); } catch (Exception e) { e.printStackTrace(); } } public void compileClass() { String filePath = new File(CreateClass.class.getClassLoader() .getResource("").getFile()).getAbsolutePath(); String[] source = { "-d", filePath, new String(CLASS_FILE) }; System.out.println("javac out:" + com.sun.tools.javac.Main.compile(source)); } public void runClass() { try { Class params[] = {}; Object paramsObj[] = {}; Class testClass = Class.forName(CLASS_NAME); Object iClass = testClass.newInstance(); Method thisMethod = testClass.getDeclaredMethod("println", params); thisMethod.invoke(iClass, paramsObj); } catch (Exception e) { e.printStackTrace(); } } }  
需要引入%JAVA_HOME%/lib/tools.jar;這也是我遇到的tools.jar的唯一一個用途呵呵.

原文網址：http://blog.csdn.net/sunyujia/archive/2008/05/02/2359194.aspx