struts2初学实现用户显示

刚刚开始学习struts2，就从最简单的增删查改开始做吧。

今天就先完成显示功能的是实现吧

首先在开始做之前我们需要对struts2项目进行配置

其中mysql-connector-java-5.1.45是数据库jar包，jstl和standard是el表达式使用的包，其余就是struts最基本的jar包

完成jar包之后便是web.xml和struts2.xml的配置了

首先web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app id="starter" version="2.4"
         xmlns="http://java.sun.com/xml/ns/j2ee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
  
    <display-name>struts2</display-name>
    <display-name>Struts 2 Rest Example</display-name>
  <!-- Filters -->
  <!-- START SNIPPET: filter -->
    <filter>
        <filter-name>action2</filter-name>
        <filter-class>org.apache.struts2.dispatcher.filter.StrutsPrepareAndExecuteFilter</filter-class>
    </filter>
    <!-- END SNIPPET: filter -->

    <filter-mapping>
        <filter-name>action2</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

    <!-- Welcome file lists -->
    <welcome-file-list>
        <welcome-file>index.jsp</welcome-file>
    </welcome-file-list>
    
</web-app>

struts2.xml

<?xml version="1.0" encoding="UTF-8" ?>

<!DOCTYPE struts PUBLIC
        "-//Apache Software Foundation//DTD Struts Configuration 2.5//EN"
        "http://struts.apache.org/dtds/struts-2.5.dtd">
<struts>

</struts>

这里我们暂时还没有写功能所以什么都没有，如果是在官方测试包中提取的struts2。xml中间有一些东西，需要手动删除

在完成了这些之后运行服务器看是否报错，若无错误便是struts2配置完成

第一步创建 用户类

package model;

public class UserModel {
    
    private int id;
    private String userName;
    private String pwd;
    
    public UserModel(){}

    public UserModel(int id, String userName, String pwd) {
        super();
        this.id = id;
        this.userName = userName;
        this.pwd = pwd;
    }
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getUserName() {
        return userName;
    }
    public void setUserName(String userName) {
        this.userName = userName;
    }
    public String getPwd() {
        return pwd;
    }
    public void setPwd(String pwd) {
        this.pwd = pwd;
    }

}

第二步创建 Dao类

package dao;

import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

import javax.security.auth.message.callback.PrivateKeyCallback.Request;

import model.UserModel;
import utils.JDBCUtil;

public class UserDao {
    private String sql = "";
    
    public List<UserModel> selectUser(){
        sql="select * from user";
        boolean flag = false;
        ResultSet rs = JDBCUtil.doQuery(sql);
        List<UserModel> uList = new ArrayList<UserModel>();
        try {
            while(rs.next()){
                UserModel uModel = new UserModel(
                        Integer.parseInt(rs.getString("id")),
                        rs.getString("userName"),
                        rs.getString("pwd"));
                uList.add(uModel);
                
            }
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return uList;
    }

}

第三步编写Action

package action;

import java.util.List;

import javax.servlet.http.HttpServletRequest;

import org.apache.struts2.ServletActionContext;

import dao.UserDao;
import model.UserModel;

public class DisplayAction {
    private UserModel user;

    public UserModel getUser() {
        return user;
    }

    public void setUser(UserModel user) {
        this.user = user;
    }
    public String execute(){
        UserDao dao = new UserDao();
        List<UserModel> uList = dao.selectUser();
        HttpServletRequest request = ServletActionContext.getRequest();   
        request.setAttribute("userList", uList);  
        return "success";
    }
}

在这里我们将数据库取出的数据全部存入request中方便jsp页面使用el表达式来提取

呢么完成这些后struts2的后台已经完成了，最重要的一步配置struts2.xml

<?xml version="1.0" encoding="UTF-8" ?>

<!DOCTYPE struts PUBLIC
        "-//Apache Software Foundation//DTD Struts Configuration 2.5//EN"
        "http://struts.apache.org/dtds/struts-2.5.dtd">
<struts>
    
    <package name="user" namespace="/" extends="struts-default">
        <action name="display" class="action.DisplayAction" method="execute">
            <result name="success" type="dispatcher">/display.jsp</result>
        </action>
    </package>
</struts>

这里其中namespace的作用便是 如果你写的是 / a 呢么在你访问的页面路径之前都会有/a 如果只写 / 呢么无影响 extends 这里内容固定不变。

下面action 中 name 表示访问的名称， class表示访问的直至 ，method 表示访问的方法

result 表示重定向

最后两个jsp的页面

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">
    
    <title>功能模板页面</title>
    <meta http-equiv="pragma" content="no-cache">
    <meta http-equiv="cache-control" content="no-cache">
    <meta http-equiv="expires" content="0">    
    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    <meta http-equiv="description" content="This is my page">
  </head>
  
  <body>
      <a href="display">显示</a>
  </body>
</html>

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">
    
    <title>My JSP 'display.jsp' starting page</title>
    
    <meta http-equiv="pragma" content="no-cache">
    <meta http-equiv="cache-control" content="no-cache">
    <meta http-equiv="expires" content="0">    
    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    <meta http-equiv="description" content="This is my page">


  </head>
  
  <body>
      <table>
        <tr><th>id</th><th>昵称</th><th>密码</th></tr>
        <c:forEach items="${userList}" var="user">
            <tr><td>${user.id }</td><td>${user.userName }</td><td>${user.pwd }</td></tr>
          </c:forEach>
      </table>
  </body>
</html>

 

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