Java中的类反射与动态代理详解

package cn.juwatech.reflectionexample;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
public class ReflectionDemo {
    public static void main(String[] args) throws ClassNotFoundException {
        Class<?> clazz = Class.forName("cn.juwatech.reflectionexample.Person");
        // 获取类名
        System.out.println("类名：" + clazz.getName());
        // 获取类的字段信息
        System.out.println("字段信息：");
        Field[] fields = clazz.getDeclaredFields();
        for (Field field : fields) {
            System.out.println(field.getName() + " - " + field.getType());
        }
        // 获取类的方法信息
        System.out.println("方法信息：");
        Method[] methods = clazz.getDeclaredMethods();
        for (Method method : methods) {
            System.out.print(method.getName() + "(");
            Class<?>[] parameterTypes = method.getParameterTypes();
            for (int i = 0; i < parameterTypes.length; i++) {
                System.out.print(parameterTypes[i].getName());
                if (i < parameterTypes.length - 1) {
                    System.out.print(", ");
                }
            }
            System.out.println(") - " + method.getReturnType().getName());
        }
    }
}

package cn.juwatech.proxyexample;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
interface UserService {
    void save();
}
class UserServiceImpl implements UserService {
    public void save() {
        System.out.println("保存用户信息");
    }
}
public class DynamicProxyDemo {
    public static void main(String[] args) {
        UserService userService = new UserServiceImpl();
        UserService proxy = (UserService) Proxy.newProxyInstance(
                UserServiceImpl.class.getClassLoader(),
                UserServiceImpl.class.getInterfaces(),
                new InvocationHandler() {
                    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
                        System.out.println("开启事务");
                        Object result = method.invoke(userService, args);
                        System.out.println("提交事务");
                        return result;
                    }
                });
        proxy.save();
    }
}