Struts2環境搭建並演示用戶登陸小例子

1）搭建Struts2環境
1）引入jar包
需要的jar包有：Struts2基本jar包，mysql連接jar包。Struts2 jar包引入Struts2壓縮包struts-2.3.30\apps\struts2-blank\WEB-INF\lib目錄下的所有jar即可。
2）配置web.xml
配置web.xml可以從struts-2.3.30\apps\struts2-blank例子程序中copy

<?xml version="1.0" encoding="UTF-8"?>
<web-app id="WebApp_9" 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>Struts Blank</display-name>

    <filter>
        <filter-name>struts2</filter-name>
        <filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</filter-class>
    </filter>

    <filter-mapping>
        <filter-name>struts2</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

    <welcome-file-list>
        <welcome-file>index.html</welcome-file>
    </welcome-file-list>

</web-app>

3)配置Struts.xml
同上，也可以從例子程序中copy之後做修改

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE struts PUBLIC
    "-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"
    "http://struts.apache.org/dtds/struts-2.3.dtd">

<struts>
    <constant name="struts.devMode" value="true" />

    <package name="user" namespace="/" extends="struts-default">
        <!-- global-results表示package中action通用的跳轉方式 -->
        <global-results>
            <result name="main">/main.jsp</result>
        </global-results>
        <!-- action標籤中method可以省略，method方法名默認爲execute -->
        <action name="checkLogin" class="action.checkLoginAction" method="execute">
        </action>
    <!-- 這種action配置方式，訪問url checkLogin時會訪問到checkLoginAction類的execute方法-->
    </package>  

</struts>

配置好了之後環境如下

下面演示用Struts2做一個用戶登陸小例子
小例子用到的內容：JDBC+MySql+Struts2
1)JDBC連接

package db;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
public class DbLib {
    public static Connection getConn() throws ClassNotFoundException, SQLException{
        Connection conn;
        Class.forName("com.mysql.jdbc.Driver");
        String url="jdbc:mysql://localhost:3306/struts2"; 
        conn=DriverManager.getConnection(url,"root","199512");
        return conn;
    }
}

2)JavaBean編寫
Struts2無需繼承任何類

package model;


public class User{
    private int id;
    private String userName;
    private String 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;
    }
    @Override
    public String toString() {
        return "User [id=" + id + ", userName=" + userName + ", pwd=" + pwd + "]";
    }
}

3)編寫數據庫連接類
爲action類提供連接數據庫方法

package dao;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;

import db.DbLib;
import model.User;

public class UserDAO {
    private String sql;
    public boolean checkLogin(User user) throws ClassNotFoundException, SQLException
    {
        Connection conn = DbLib.getConn();
        sql="select count(*) from users where userName=? and pwd=?";
        PreparedStatement ps = conn.prepareStatement(sql);
        ps.setString(1,user.getUserName());
        ps.setString(2,user.getPwd());
        ResultSet rs = ps.executeQuery();
        boolean flag=false;
        rs.next();
        if(rs.getInt(1)==0)
        {
            flag=true;
        }
        conn.close();
        return flag;
    }
}

4）測試用戶可否登陸checkLoginAction編寫
樓主這裏用了繼承ActionSupport類重寫execute的方法。 Struts2 action可以不繼承任何類，自己添加execute方法。也可以繼承ActionSupport類，或者實現Action接口來添加execute方法。

package action;

import java.io.PrintWriter;

import javax.servlet.http.HttpSession;

import org.apache.struts2.ServletActionContext;
import com.opensymphony.xwork2.ActionSupport;
import com.opensymphony.xwork2.ModelDriven;

import dao.UserDAO;
import model.User;

public class checkLoginAction extends ActionSupport implements ModelDriven<User>{
    private UserDAO dao = new UserDAO();
    private User user=new User();//定義並初始化一個模型
    public User getUser() {
        return user;
    }
    public void setUser(User user) {
        this.user = user;
    }
    @Override
    public String execute() throws Exception {
        // TODO Auto-generated method stub
        PrintWriter out = ServletActionContext.getResponse().getWriter();
        HttpSession session = ServletActionContext.getRequest().getSession();
        session.setAttribute("USER", user);
        if(dao.checkLogin(user))
        {
            out.print("1");
        }
        return null;
    }
    //給模型添加屬性
    @Override
    public User getModel() {
        // TODO Auto-generated method stub
        return user;
    }

}

用戶登陸界面
注意struts中訪問action的方式。

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
<script type="text/javascript" src="jslib/jquery-3.0.0.js"></script>
<script type="text/javascript">
    $(function(){
        $("[type='button']").click(function(){
            $.post("checkLogin",{userName:$("[name='user']").val(),pwd:$("[name='pwd']").val()},function(data){
                if(data=="1")
                {
                    $("#info").html("用戶名或者密碼錯誤,請重新輸入");
                }
                else
                {
                    location.href="main.jsp";
                }
            })
        })
    })
</script>
</head>
<body>
    <table>
        <tr><td>用戶名</td><td><input type="text" name="user"></td></tr>
        <tr><td>密碼</td><td><input type="password" name="pwd"></td></tr>
        <tr><td colspan="2"><input type="button" value="登陸"></td></tr>
    </table>
    <div id="info"></div>
</body>

</html>