Java反射机制

第一种方法

调用处

public String invokeMethod(Map<String, String> params) throws NoSuchMethodException, InvocationTargetException, IllegalAccessException {
        ApplicationContext applicationContext = ApplicationContextHolder.getApplicationContext();
        Class<?>  aClass = applicationContext.getBean("UserService").getClass();
        Method method = aClass.getDeclaredMethod("selectUser", String.class);
        Map<String, String> data = new HashMap<String, String>();
        data.put("listId", "123");
        CommonResult result = (CommonResult) method.invoke(applicationContext.getBean("UserService"),"吕茹花");
        log.info(result.toString());
        return "aa";
    }

ApplicationContextHolder.java

package com.baidu.aduhdmap.platform.common;

import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.stereotype.Service;

@Service("applicationContextProvider")
public class ApplicationContextHolder implements ApplicationContextAware {
    private static ApplicationContext appContext;

    /**
     *
     * @param ctx
     * @throws BeansException
     */
    @Override
    public void setApplicationContext(ApplicationContext ctx) throws BeansException {
        ApplicationContextHolder.appContext = ctx;
    }

    /**
     *
     * @return
     */
    public static ApplicationContext getApplicationContext() {
        return appContext;
    }

}

第二种 动态代理

调用处

public class UserProxyTest { 

@Test
public void test() { 

IUserDao target = new UserDao();
System.out.println("目标对象信息：" + target.getClass());
//获取代理类实例对象
IUserDao proxy = (IUserDao) new UserProxy(target).getProxyInstance();
System.out.println("代理对象信息：" + proxy.getClass());
//执行代理方法
proxy.insert();
}
}

UserProxy.java

package com.baidu.aduhdmap.platform.common;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;

public class UserProxy {

    private Object target; //目标对象
    public UserProxy(Object target) {

        this.target = target;
    }
    /** * 利用JDK API获取到代理对象 * @return */
    public Object getProxyInstance() {

//目标对象的加载器
        ClassLoader loader = target.getClass().getClassLoader();
//目标对象的实现接口类型
        Class<?>[] interfaces = target.getClass().getInterfaces();
//InnvocationHandler事件处理器实例对象
        InvocationHandler h = new InvocationHandler() {

            @Override
            public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {

                System.out.println("添加数据前：手动开启事务");
// 执行目标对象方法
                Object value = method.invoke(target, args);
                System.out.println("添加数据后：手动提交事务");
                return null;
            }
        };
//传入3个参数，创建代理类的实例对象，并返回
        return Proxy.newProxyInstance(loader, interfaces,h);
    }
}

参考 https://javaforall.cn/172696.html