JAVAEE - Implementation of custom interceptors, struts2 tags, login functions and verification login interceptors

1. Custom interceptor

1. Architecture

2. Interceptor creation

//拦截器:第一种创建方式//拦截器生命周期:随项目的启动而创建,随项目关闭而销毁public class MyInterceptor implements Interceptor{}

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//创建方式2: 继承AbstractInterceptor -> struts2的体贴//帮我们空实现了init 和 destory方法. 我们如果不需要实现这两个方法,就可以只实现intercept方法public class MyInterceptor2 extends AbstractInterceptor{}

//创建方式3:继承MethodFilterInterceptor 方法过滤拦截器//功能: 定制拦截器拦截的方法.// 定制哪些方法需要拦截.// 定制哪些方法不需要拦截public class MyInterceptor3 extends MethodFilterInterceptor{}

3. Interceptor api

//放行String result = invocation.invoke();

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//前处理System.out.println("MyInterceptor3 的前处理!");//放行String result = invocation.invoke();//后处理System.out.println("MyInterceptor3 的后处理!");

//不放行,直接跳转到一个结果页面//不执行后续的拦截器以及Action,直接交给Result处理结果.进行页面跳转return "success";

  add,delete /index.jsp

/login.jsp

1. Tag system

## 2.struts2 tag structure

3. Control tags

Prepare Action and then go to jsp to practice struts2 tags

public class Demo2Action extends ActionSupport {public String execute() throws Exception { List list = new ArrayList<>(); list.add("tom"); list.add("jerry"); list.add("jack"); list.add("rose"); list.add("hqy"); ActionContext.getContext().put("list", list);return SUCCESS; } }

<%@ taglib prefix="s" uri="/struts-tags" %>

|
list长度为4!list长度为3!list不3不4!

this.addActionError("我是错误信息 哈哈哈");

public class UserAction extends ActionSupport implements ModelDriven {private User user = new User();private UserService us = new UserServiceImpl(); public String login() throws Exception {//1 调用Service 执行登陆操作User u = us.login(user);//2 将返回的User对象放入session域作为登陆标识ActionContext.getContext().getSession().put("user", u);//3 重定向到项目的首页return "toHome"; } @Overridepublic User getModel() {return user; } }

Service layer code:

public class UserServiceImpl implements UserService {private UserDao ud = new UserDaoImpl(); @Overridepublic User login(User user) {//打开事务 HibernateUtils.getCurrentSession().beginTransaction();//1.调用Dao根据登陆名称查询User对象User existU = ud .getByUserCode(user.getUser_code());//提交事务 HibernateUtils.getCurrentSession().getTransaction().commit(); if(existU==null){//获得不到=>抛出异常提示用户名不存在throw new RuntimeException("用户名不存在!"); }//2 比对密码是否一致if(!existU.getUser_password().equals(user.getUser_password())){//不一致=>抛出异常提示密码错误throw new RuntimeException("密码错误!"); }//3 将数据库查询的User返回return existU; } }

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Dao layer code:

public class UserDaoImpl implements UserDao { @Overridepublic User getByUserCode(String user_code) {//HQL查询//1.获得SessionSession session = HibernateUtils.getCurrentSession();//2 书写HQLString hql = "from User where user_code = ? ";//3 创建查询对象Query query = session.createQuery(hql);//4 设置参数query.setParameter(0, user_code);//5 执行查询User u = (User) query.uniqueResult();return u; } }

Core code:

login/login.jsp /jsp/customer/list.jsp CustomerAction_list / /index.htm/login.jsp

Supplementary knowledge: Check whether the parent page of the current page is itself, not If so, jump to solve the page nesting problem.

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