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JavaBean+servlet+jsp——>对数据进行增删改查

1.开始页面（查询数据）

 1 <%@page import="com.zdsofe.work.Student"%>
 2 <%@page import="java.util.List"%>
 3 <%@page import="com.zdsofe.work.ReadData"%>
 4 <%@ page language="java" contentType="text/html; charset=UTF-8"
 5     pageEncoding="UTF-8"%>
 6 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
 7 <html>
 8 <head>
 9 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
10 <title>Insert title here</title>
11 </head>
12 <body>
13 <% ReadData rd=new ReadData();
14   List<Student> list= rd.findInfo();
15 %>
16 
17 <table border="1">
18 <tr>
19 <th>序号</th>
20 <th>名字</th>
21 <th>密码</th>
22 <th>操作</th>
23 </tr>
24 
25 
26 <%
27 for(int i=0;i<list.size();i++)
28 {
29     %>
30     <tr>
31     <td><%=list.get(i).getId()%></td>
32     <td><%=list.get(i).getUserName()%></td>
33     <td><%=list.get(i).getMima()%></td>
34     <td><a href="../servlet?userN=<%=list.get(i).getUserName()%>">修改</a>
35         <a href="../DeleteServlet?userI=<%=list.get(i).getId()%>">删除</a>
36     </td>
37     </tr>
38 <% 
39   }
40 %>
41 
42 </table>
43 </body>
44 </html>

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2.获取数据的servlet

 1 package com.zdsofe.work;
 2 
 3 import java.io.IOException;
 4 import java.sql.ResultSet;
 5 import java.sql.SQLException;
 6 import java.sql.Statement;
 7 
 8 import javax.servlet.ServletException;
 9 import javax.servlet.annotation.WebServlet;
10 import javax.servlet.http.HttpServlet;
11 import javax.servlet.http.HttpServletRequest;
12 import javax.servlet.http.HttpServletResponse;
13 import javax.servlet.http.HttpSession;
14 
15 import com.zdsofe.util.DBUtil;
16 
17 /**
18  * Servlet implementation class servlet
19  */
20 @WebServlet("/servlet")
21 public class servlet extends HttpServlet {
22     private static final long serialVersionUID = 1L;
23        
24     /**
25      * @see HttpServlet#HttpServlet()
26      */
27     public servlet() {
28         super();
29         // TODO Auto-generated constructor stub
30     }
31 
32     /**
33      * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
34      */
35     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
36         //解决乱码问题
37         request.setCharacterEncoding("utf-8");
38         response.setCharacterEncoding("utf-8");
39         response.setContentType("text/html charset=utf-8");
40       
41        //获取用户名：
42         String userName = request.getParameter("userN");
43         
44        //根据用户名查询某一条用户信息
45         Student stu=ReadData.findUserByName(userName);
46         HttpSession session = request.getSession();
47         session.setAttribute("user", stu);
48         session.setAttribute("title", "修改用户");
49         response.sendRedirect("/webProject2/pages/edit.jsp");
50     }
51 
52     /**
53      * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
54      */
55    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
56                 
57         
58     }
59 
60 }

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3.修改页面

 1 <%@page import="com.zdsofe.work.Student"%>
 2 <%@ page language="java" contentType="text/html; charset=UTF-8"
 3     pageEncoding="UTF-8"%>
 4 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
 5 <html>
 6 <head>
 7 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
 8 <title>Insert title here</title>
 9 </head>
10 
11 <%
12 //获取用户信息
13    Student stu=(Student)session.getAttribute("user");
14 %>
15 <body>
16 
17 <form action="../EditServlet" method="get">
18 
19 用户名：<input type="text" name="userName" value="<%=stu.getUserName()%>"><br/>
20 密码：<input type="password" name="mima" value="<%=stu.getMima()%>"><br/>
21 <button type="submit">提交</button>
22 
23 </form>
24 
25 </body>
26 </html>

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4.修改数据的servlet

 1 package com.zdsofe.work;
 2 
 3 import java.io.IOException;
 4 import java.lang.reflect.InvocationTargetException;
 5 import java.util.Enumeration;
 6 import java.util.HashMap;
 7 import java.util.Map;
 8 
 9 import javax.servlet.ServletException;
10 import javax.servlet.annotation.WebServlet;
11 import javax.servlet.http.HttpServlet;
12 import javax.servlet.http.HttpServletRequest;
13 import javax.servlet.http.HttpServletResponse;
14 
15 import org.apache.commons.beanutils.BeanUtils;
16 
17 /**
18  * Servlet implementation class EditServlet
19  */
20 @WebServlet("/EditServlet")
21 public class EditServlet extends HttpServlet {
22     private static final long serialVersionUID = 1L;
23        
24     /**
25      * @see HttpServlet#HttpServlet()
26      */
27     public EditServlet() {
28         super();
29         // TODO Auto-generated constructor stub
30     }
31 
32     /**
33      * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
34      */
35     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
36                 //请求和响应页面的编码格式修改
37                 
38                 request.setCharacterEncoding("UTF-8");
39                 response.setCharacterEncoding("utf-8");
40                 response.setContentType("text/html charset=utf-8");
41                 /*//获取表单中的所用控件name属性
42                 Enumeration<String> en = request.getParameterNames();
43                 Map<String, Object> mapObj = new HashMap<>();
44                 //实例化一个Student对象
45                 Student stu=new Student();
46                 while(en.hasMoreElements())
47                 {
48                     String rs = en.nextElement();
49                     mapObj.put(rs, request.getParameter("rs"));
50                 }
51                 try {
52                     BeanUtils.populate(stu, mapObj);
53                 
54                     
55                 } catch (IllegalAccessException | InvocationTargetException e) {
56                     e.printStackTrace();
57                 }*/
58                 String name=request.getParameter("userName");
59                 String mima=request.getParameter("mima");
60                 Student stu=new Student(name,mima);
61                 //根据条件修改用户信息，调用执行sql方法
62                 
63                 int upResult = ReadData.update(stu);
64                 
65                 if(upResult==1)
66                 {
67                     response.sendRedirect(request.getContextPath()+"/pages/student.jsp");
68                 }
69             
70     }
71 
72     /**
73      * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
74      */
75     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
76         // TODO Auto-generated method stub
77     }
78 
79 }

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5.删除数据的servlet

 1 package com.zdsofe.work;
 2 
 3 import java.io.IOException;
 4 import java.sql.SQLException;
 5 import java.sql.Statement;
 6 
 7 import javax.servlet.ServletException;
 8 import javax.servlet.annotation.WebServlet;
 9 import javax.servlet.http.HttpServlet;
10 import javax.servlet.http.HttpServletRequest;
11 import javax.servlet.http.HttpServletResponse;
12 
13 import com.zdsofe.util.DBUtil;
14 
15 /**
16  * Servlet implementation class DeleteServlet
17  */
18 @WebServlet("/DeleteServlet")
19 public class DeleteServlet extends HttpServlet {
20     private static final long serialVersionUID = 1L;
21        
22     /**
23      * @see HttpServlet#HttpServlet()
24      */
25     public DeleteServlet() {
26         super();
27         // TODO Auto-generated constructor stub
28     }
29 
30     /**
31      * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
32      */
33     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
34 
35                 //获取要删除的用户ID
36                 String userId = request.getParameter("userI");
37                 //删除的sql语句
38                 String sql = "delete from denglu  where id = "+userId+"";
39                 
40             try {
41                 Statement stam=    DBUtil.getConnection().createStatement();
42                 stam.executeUpdate(sql);
43             } catch (SQLException e) {
44                 // TODO Auto-generated catch block
45                 e.printStackTrace();
46             }
47             response.sendRedirect(request.getContextPath()+"/pages/student.jsp");
48     }
49 
50     /**
51      * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
52      */
53     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
54         // TODO Auto-generated method stub
55     }
56 
57 }

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6.javaBean(实体类)

 1 package com.zdsofe.work;
 2 
 3 public class Student {
 4  public String id;
 5  public  String userName;
 6  public  String mima;
 7  
 8 public Student(String id, String userName, String mima) {
 9     super();
10     this.id = id;
11     this.userName = userName;
12     this.mima = mima;
13 }
14 
15 public Student(String userName, String mima) {
16     
17     this.userName = userName;
18     this.mima = mima;
19 }
20 
21 public Student() {
22     super();
23 }
24 
25 public String getId() {
26     return id;
27 }
28 public void setId(String id) {
29     this.id = id;
30 }
31 public String getUserName() {
32     return userName;
33 }
34 public void setUserName(String userName) {
35     this.userName = userName;
36 }
37 public String getMima() {
38     return mima;
39 }
40 public void setMima(String mima) {
41     this.mima = mima;
42 }
43  
44  
45  
46 
47 }

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7.方法

 1 package com.zdsofe.work;
 2 
 3 import java.sql.ResultSet;
 4 import java.sql.SQLException;
 5 import java.sql.Statement;
 6 import java.util.ArrayList;
 7 import java.util.List;
 8 
 9 import com.zdsofe.util.DBUtil;
10 
11 
12 
13 public class ReadData {
14     
15     //查询信息
16     public static List<Student> findInfo() {
17         
18         
19         List <Student>list=new ArrayList<>();
20         //调用连接并创建SQL语句
21         try {
22             Statement stam= DBUtil.getConnection().createStatement();
23             String sql="SELECT id,userName,mima FROM  denglu;";
24             ResultSet rs=stam.executeQuery(sql);
25             while(rs.next())
26             {
27                 String id=rs.getString("id");
28                 String userName=rs.getString("userName");
29                 String mima=rs.getString("mima");
30                 Student stu=new Student(id,userName,mima);
31                 list.add(stu);
32             }
33             
34         } catch (SQLException e) {
35             e.printStackTrace();
36             
37         }
38         return list;
39     }
40             
41      /* 根据用户名查询用户信息
42      * @param userName
43      * @return
44      */
45     public static Student findUserByName(String userName)
46     {
47         Student stu=null;
48         //输出查询sql
49         String sql = "select * from denglu t where t.userName='"+userName+"'";
50         try {
51             //调用连接并创建SQL语句
52             Statement stam= DBUtil.getConnection().createStatement();
53             
54             ResultSet rs=stam.executeQuery(sql);
55             if(rs.next())
56             {
57                 String id=rs.getString("id");
58                 String name=rs.getString("userName");
59                 String mima=rs.getString("mima");
60                 stu=new Student(id,name,mima);                      
61             }
62             
63         } catch (SQLException e) {
64             e.printStackTrace();
65             
66         }
67         return stu;
68     }
69     
70     /**
71      * 根据编码修改用户信息
72      * @param user
73      * @return
74      */
75     public static int update(Student stu)
76     {
77         //执行sql的结果
78         int result = 0;
79         //更新sql
80         
81         String sql = "update denglu t set t.mima = '"+stu.getMima()+"' where t.userName ='"+stu.getUserName()+"'";
82         try {
83         Statement stam=    DBUtil.getConnection().createStatement();
84             result=stam.executeUpdate(sql);
85             
86         } catch (SQLException e) {
87             e.printStackTrace();
88         }
89         
90         
91         return result;
92     }
93 }

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8.连接数据库的包装类

 1 package com.zdsofe.util;
 2 
 3 import java.sql.Connection;
 4 import java.sql.DriverManager;
 5 import java.sql.SQLException;
 6 
 7 public class DBUtil {
 8     private static String DRIVER="com.mysql.jdbc.Driver";
 9     private static String URL="jdbc:mysql://localhost:3306/mysql";
10     private static String user="root";
11     private static String key="775297";
12     public static Connection conn;
13     
14     //加载驱动
15         static{
16             try {
17                 Class.forName(DRIVER);
18             } catch (ClassNotFoundException e) {
19                 e.printStackTrace();
20             }
21         }
22         //连接数据库
23         public static Connection getConnection(){
24          try {
25             conn = DriverManager.getConnection(URL, user, key);
26         } catch (SQLException e) {
27             e.printStackTrace();
28         }
29             return conn;
30         }
31 }

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原文地址：https://www.cnblogs.com/zclqian/p/7248350.html