为没有实现接口的类提供代理
更好的性能
原理：动态生成需要代理的子类，子类重写代理类的非final方法。子类中采用方法拦截的奇数拦截所有父类的方法的调用，顺势织入横切逻辑。
底层：使用ASM字节码处理框架。
缺点：无法代理fianl方法。
Spring AOP
net.sf.cglib.transform: 编译期或运行期类和类文件的转换
net.sf.cglib.proxy: 实现创建代理和方法拦截器的类
net.sf.cglib.reflect: 实现快速反射和C#风格代理的类
net.sf.cglib.util: 集合排序等工具类
net.sf.cglib.beans: JAVABean相关的工具类
package com.cclu.cglibproxy;import java.util.HashMap;import java.util.Map;/*** @author ChangCheng Lu* @date 2023/8/20 15:59*/public class UserService {private static final Map<String, String> nameMap;private static final Map<String, String> addressMap;static {nameMap = new HashMap<>(3);nameMap.put("1001", "木子");nameMap.put("1002", "小一");nameMap.put("1003", "阿同");addressMap = new HashMap<>(3);addressMap.put("1001", "涟水");addressMap.put("1002", "淮安");addressMap.put("1003", "上海");}public String getUserNameById(String userId) {return nameMap.get(userId);}public String getAddressById(String userId) {return addressMap.get(userId);}}
package com.cclu.cglibproxy;import net.sf.cglib.proxy.MethodInterceptor;import net.sf.cglib.proxy.MethodProxy;import java.lang.reflect.Method;/*** @author ChangCheng Lu* @date 2023/8/20 16:04*/public class LogInterceptor implements MethodInterceptor {@Overridepublic Object intercept(Object o, Method method, Object[] objects, MethodProxy methodProxy) throws Throwable {System.out.println("方法调用前...");Object res = methodProxy.invokeSuper(o, objects);System.out.println("方法调用后："+res);return res;}}
package com.cclu.cglibproxy;import net.sf.cglib.proxy.Enhancer;/*** @author ChangCheng Lu* @date 2023/8/20 16:10*/public class Client {public static void mAIn(String[] args) {Enhancer enhancer = new Enhancer();enhancer.setSuperclass(UserService.class);enhancer.setCallback(new LogInterceptor());UserService userService = (UserService) enhancer.create();userService.getUserNameById("1001");userService.getAddressById("1003");}}
package com.cclu.cglibproxy;import java.util.HashMap;import java.util.Map;/*** @author ChangCheng Lu* @date 2023/8/20 15:59*/public class UserService {private static final Map<String, String> nameMap;private static final Map<String, String> addressMap;static {nameMap = new HashMap<>(3);nameMap.put("1001", "木子");nameMap.put("1002", "小一");nameMap.put("1003", "阿同");addressMap = new HashMap<>(3);addressMap.put("1001", "苏州");addressMap.put("1002", "淮安");addressMap.put("1003", "上海");}public String getUserNameById(String userId) {return nameMap.get(userId);}public String getAddressById(String userId) {return addressMap.get(userId);}}
package com.cclu.cglibproxy;import net.sf.cglib.proxy.CallbackFilter;import java.lang.reflect.Method;/*** @author ChangCheng Lu* @date 2023/8/20 16:35*/public class LogInterceptorFilter implements CallbackFilter {@Overridepublic int accept(Method method) {if (method.getName().equals("getUserNameById")) {System.out.println("是不是木子？");return 1;} else if (method.getName().equals("getAddressById")) {System.out.println("是不是阿同？");return 2;}return 0;}}
package com.cclu.cglibproxy;import net.sf.cglib.proxy.FixedValue;/*** @author ChangCheng Lu* @date 2023/8/20 17:44*/public class TargetResultFixed implements FixedValue {@Overridepublic Object loadObject() throws Exception {System.out.println("锁定结果");Object obj = "苏州";return obj;}}
package com.cclu.cglibproxy;import net.sf.cglib.proxy.Callback;import net.sf.cglib.proxy.Enhancer;import net.sf.cglib.proxy.NoOp;import org.junit.Test;/*** @author ChangCheng Lu* @date 2023/8/20 17:32*/public class ProxyTest {@Testpublic void filterTest() {Enhancer enhancer = new Enhancer();enhancer.setSuperclass(UserService.class);enhancer.setCallbackFilter(new LogInterceptorFilter());enhancer.setCallbacks(new Callback[]{NoOp.INSTANCE, new LogInterceptor(), new TargetResultFixed()});UserService userService = (UserService) enhancer.create();System.out.println(userService);System.out.println(userService.getUserNameById("1001"));System.out.println(userService.getAddressById("1003"));}}
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