java实现动态编译并动态加载

 public class AlTest { public String sayHello(){ System.out.println("AlTest类 sayHello()方法正在执行...."); return "hello word"; } }

 package com.piao.job; import java.lang.reflect.Method; import javax.tools.JavaCompiler; import javax.tools.ToolProvider; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.beans.factory.annotation.Configurable; import org.springframework.scheduling.annotation.EnableScheduling; import org.springframework.scheduling.annotation.Scheduled; import org.springframework.stereotype.Component; @Component @Configurable @EnableScheduling public class CompilerJob { private static final Logger logger = LoggerFactory.getLogger(CompilerJob.class); private static boolean isExecute = false; /** * 任务：job test */ @Scheduled(cron = "*/10 * * * * * ") public void test2() { try { if (isExecute) { return; } isExecute = true;		//只是测试，所以只执行一次 complierAndRun(); } catch (Exception e) { logger.error("test", e); } } public void complierAndRun(){ try { System.out.println(System.getProperty("user.dir")); //动态编译 JavaCompiler javac = ToolProvider.getSystemJavaCompiler(); int status = javac.run(null, null, null, "-d", System.getProperty("user.dir")+"\\target\\classes","D:/test/AlTest.java"); if(status!=0){ System.out.println("没有编译成功！"); } //动态执行 Class clz = Class.forName("AlTest");//返回与带有给定字符串名的类 或接口相关联的 Class 对象。 Object o = clz.newInstance(); Method method = clz.getDeclaredMethod("sayHello");//返回一个 Method 对象，该对象反映此 Class 对象所表示的类或接口的指定已声明方法 String result= (String)method.invoke(o);//静态方法第一个参数可为null,第二个参数为实际传参 System.out.println(result); } catch (Exception e) { logger.error("test", e); } } }

 //生成到工程classes下 //int status = javac.run(null, null, null, "-d", System.getProperty("user.dir")+"\\target\\classes","D:/test/AlTest.java"); //生成到BootStrap ClassLoader可加载目录下 int status = javac.run(null, null, null, "-d", "C:\\Program Files\\Java\\jdk1.8.0_65\\jre\\classes","D:/test/AlTest.java");

 public void complierAndRun(){ try { System.out.println(System.getProperty("user.dir")); //动态编译 JavaCompiler javac = ToolProvider.getSystemJavaCompiler(); int status = javac.run(null, null, null, "-d", "D:\\","D:/test/AlTest.java"); if(status!=0){ System.out.println("没有编译成功！"); } //动态执行 //Class clz = Class.forName("AlTest");//返回与带有给定字符串名的类 或接口相关联的 Class 对象。 //自定义类加载器的加载路径 MyClassLoader myClassLoader = new MyClassLoader("D:\\"); //包名+类名 Class clz = myClassLoader.loadClass("AlTest"); Object o = clz.newInstance(); Method method = clz.getDeclaredMethod("sayHello");//返回一个 Method 对象，该对象反映此 Class 对象所表示的类或接口的指定已声明方法 String result= (String)method.invoke(o);//静态方法第一个参数可为null,第二个参数为实际传参 System.out.println(result); } catch (Exception e) { logger.error("test", e); } }

 public class ScriptUtils { private static final Logger logger = LoggerFactory.getLogger(ScriptUtils.class); /** * * 
执行字符串计算
 * @param express * @param params * @return * @throws ScriptException */ @SuppressWarnings("unchecked") public static  E eval(String express, Map params) throws ScriptException{ ScriptEngineManager manager = new ScriptEngineManager(); ScriptEngine engine = manager.getEngineByName("js"); if(params == null){ params = new HashMap(); } Iterator> iter = params.entrySet().iterator(); Map.Entry entry = null; while(iter.hasNext()){ entry = iter.next(); engine.put(entry.getKey(), entry.getValue()); } E result = null; try { result = (E)engine.eval(express); } catch (ScriptException e) { logger.warn("表达式执行异常： " + e.getMessage()); } return result; } /** * 解析字符串， 并将其当作表达式执行 * @param express * @param params * @return * @throws ScriptException */ public static  Boolean evalBoolean(String express, Map params) { ScriptEngineManager manager = new ScriptEngineManager(); ScriptEngine engine = manager.getEngineByName("js"); if(params == null){ params = new HashMap(); } Iterator> iter = params.entrySet().iterator(); Map.Entry entry = null; while(iter.hasNext()){ entry = iter.next(); engine.put(entry.getKey(), entry.getValue()); } Boolean result = null; try { result = (Boolean)engine.eval(express); } catch (ScriptException e) { result = false; logger.warn("表达式执行异常： " + e.getMessage()); } return result; }