本案例需要用到本站的【JAVAEE】运用MVC+DAO设计查询所有用户信息 此文章中的com/bean/DbConnect.java和com/bean/User.java两个javaBean类。
1.创建查询页面
byname.jsp
[sourcecode language=”html” title=”byname.jsp”]<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ taglib prefix="c"
uri="http://java.sun.com/jsp/jstl/core" %>
<!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>
</head>
<body>
<form action="FindByNameServlet" method="post">
<input type="text" name="username">
<input type="submit" value="按照账号查找">
</form>
<c:if test="${requestScope.u!=null }" >
<c:if test="${requestScope.u.id==0 }" >
查询的用户不存在
</c:if>
<c:if test="${requestScope.u.id>=1 }" >
<table>
<tr>
<td>id</td>
<td>用户名</td>
<td>用户密码</td>
<td>权限</td>
</tr>
<tr>
<td>${requestScope.u.id }</td>
<td>${requestScope.u.name }</td>
<td>${requestScope.u.pwd }</td>
<td>${requestScope.u.power }</td>
</tr>
</table>
</c:if>
</c:if>
</body>
</html>[/sourcecode]
2.创建处理的dao类
com/dao/UserDao.java
[sourcecode language=”java” title=”UserDao.java”]
package com.dao;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.Statement;
import java.util.ArrayList;
import com.bean.DbConnect;
import com.bean.User;
public class UserDao {
public User findUserByname(String name) {
User user1=null;
try{
Connection conn;
conn = DbConnect.getDBconnection();
Statement stmt = conn.createStatement();
String sql="select * from benzhu_user where user_name=’"+name+"’";
ResultSet rs=stmt.executeQuery(sql);
if(rs.next()) {
int id = rs.getInt(1);
String name1 = rs.getString(2);
String pwd = rs.getString(3);
int power = rs.getInt(4);
user1 = new User(id,name1,pwd,power);
}
else {
int id= 0;
String name1 = "name";
String pwd = "pwd";
int power = 0;
user1 = new User(id,name1,pwd,power);
}
DbConnect.Close(conn, stmt, rs);
}
catch(Exception e){
e.printStackTrace();
}
return user1;
}
}[/sourcecode]
3.创建servlet服务器处理类
com/servlet/FindByNameServlet.java
[sourcecode language=”java” title=”example-filename.php”]
package com.servlet;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.bean.User;
import com.dao.UserDao;
@WebServlet("/FindByNameServlet")
public class FindByNameServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
String name =request.getParameter("username");
UserDao dao1 = new UserDao();
User user = dao1.findUserByname(name);
request.setAttribute("u", user);
request.getRequestDispatcher("byname.jsp").forward(request, response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request, response);
}
}[/sourcecode]
4.记得导入数据库的java驱动包和c标签包
效果图：
