Spring-cglib代理

一导入包

Spring框架中的cglib包

这时候不需要目标类和代理类的接口了

public class Person {private Long pid;private String pname;public Long getPid() {return pid;}public void setPid(Long pid) {this.pid = pid;}public String getPname() {return pname;}public void setPname(String pname) {this.pname = pname;}}

public class PersonDaoImpl{public void savePerson() {System.out.println("save person");}public void updatePerson() {System.out.println("update person");}public void deletePerson() {System.out.println("delete person");}public List<Person> getPerson() {Person person = new Person();person.setPid(1L);person.setPname("aaa");List<Person> personList = new ArrayList<Person>();personList.add(person);for(Person person2:personList){System.out.println(person2.getPname());}return personList;}}

public class Transaction {public void beginTransaction(){System.out.println("begin transaction");}public void commit(){System.out.println("commit");}}

public class PersonDaoInteceptor implements MethodInterceptor{private Transaction transaction;private Object target;public PersonDaoInteceptor(Transaction transaction,Object target){this.transaction = transaction;this.target = target;}public Object createProxy(){Enhancer enhancer = new Enhancer();enhancer.setSuperclass(this.target.getClass());//设置目标类为代理类的父类enhancer.setCallback(this);//设置拦截器为回调函数return enhancer.create();}@Overridepublic Object intercept(Object arg0, Method method, Object[] arg2,MethodProxy arg3) throws Throwable {Object obj;String methodName = method.getName();if("savePerson".equals(methodName)||"updatePerson".equals(methodName)||"deletePerson".equals(methodName)){this.transaction.beginTransaction();obj = method.invoke(this.target, arg2);//调用目标类的目标方法this.transaction.commit();}else{obj = method.invoke(this.target, arg2);//调用目标类的目标方法}return obj;}}

public class PersonDaoTest {@Testpublic void test(){Transaction transaction = new Transaction();PersonDaoImpl target = new PersonDaoImpl();PersonDaoInteceptor inteceptor = new PersonDaoInteceptor(transaction, target);PersonDaoImpl proxy = (PersonDaoImpl)inteceptor.createProxy();proxy.updatePerson();}}

cglib和jdk的动态代理：

    * jdk

        目标类和代理类实现了共同的接口

       拦截器必须实现InvocationHandler接口，而这个接口中invoke方法体的内容就是代理对象方法体的内容

        当客户端用代理对象调用方法的时候，invoke方法执行

    * cglib

         目标类是代理类的父类

        拦截器必须实现MethodInterceptor接口，而接口中的intercept方法就是代理类的方法体

         使用字节码增强机制创建代理对象的