如何使用Java實現(xiàn)動態(tài)編譯并動態(tài)加載？附詳細實例代碼

public class AlTest { 
	public String sayHello(){
		System.out.println("AlTest類 sayHello()方法正在執(zhí)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;
 
  /**
   * 任務：job test
   */
  @Scheduled(cron = "*/10 * * * * * ")
  public void test2() {
    try {
       if (isExecute) {
         return;
       }
       isExecute = true;		//只是測試，所以只執(zhí)行一次
			
	   complierAndRun();
	} catch (Exception e) {
	   logger.error("test", e);
	}
  }
	
 public void complierAndRun(){
   try {
			
	 System.out.println(System.getProperty("user.dir"));
	 //動態(tài)編譯
	 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("沒有編譯成功！");
	 }
			
	 //動態(tài)執(zhí)行
	 Class clz = Class.forName("AlTest");//返回與帶有給定字符串名的類 或接口相關(guān)聯(lián)的 Class 對象。
	 Object o = clz.newInstance();
	 Method method = clz.getDeclaredMethod("sayHello");//返回一個 Method 對象，該對象反映此 Class 對象所表示的類或接口的指定已聲明方法
	 String result= (String)method.invoke(o);//靜態(tài)方法第一個參數(shù)可為null,第二個參數(shù)為實際傳參
	 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可加載目錄下
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"));
			 //動態(tài)編譯
			JavaCompiler javac = ToolProvider.getSystemJavaCompiler();
			int status = javac.run(null, null, null, "-d", "D:\","D:/test/AlTest.java");
			if(status!=0){
				System.out.println("沒有編譯成功！");
			}
			
			//動態(tài)執(zhí)行
			//Class clz = Class.forName("AlTest");//返回與帶有給定字符串名的類 或接口相關(guān)聯(lián)的 Class 對象。
			//自定義類加載器的加載路徑
			MyClassLoader myClassLoader = new MyClassLoader("D:\");
			//包名+類名
			Class clz = myClassLoader.loadClass("AlTest");
			Object o = clz.newInstance();
			Method method = clz.getDeclaredMethod("sayHello");//返回一個 Method 對象，該對象反映此 Class 對象所表示的類或接口的指定已聲明方法
			String result= (String)method.invoke(o);//靜態(tài)方法第一個參數(shù)可為null,第二個參數(shù)為實際傳參
			System.out.println(result);
		} catch (Exception e) {
			logger.error("test", e);
		}
	}

public class ScriptUtils {
     
    private static final Logger logger = LoggerFactory.getLogger(ScriptUtils.class);
     
    /**
     * 
     * <p>執(zhí)行字符串計算</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("表達式執(zhí)行異常： " + e.getMessage());
        } 
        return result;
    }
     
    /**
     * 解析字符串， 并將其當作表達式執(zhí)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("表達式執(zhí)行異常： " + e.getMessage());
        } 
        return result;
    }