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 );

     /**

      *

      * <p>执行字符串计算</p>

      * @param express

      * @param params

      * @return

      * @throws ScriptException

      */

     @SuppressWarnings ( "unchecked" )

     public static <T, E> E eval(String express, Map<String, T> params) throws ScriptException{

         ScriptEngineManager manager = new ScriptEngineManager(); 

         ScriptEngine engine = manager.getEngineByName( "js" );

         if (params == null ){

             params = new HashMap<String,T>();

         }

         Iterator<Map.Entry<String, T>> iter = params.entrySet().iterator();

         Map.Entry<String, T> 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 <T> Boolean evalBoolean(String express, Map<String, T> params) {

         ScriptEngineManager manager = new ScriptEngineManager(); 

         ScriptEngine engine = manager.getEngineByName( "js" );

         if (params == null ){

             params = new HashMap<String,T>();

         }

         Iterator<Map.Entry<String, T>> iter = params.entrySet().iterator();

         Map.Entry<String, T> 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;

     }