Serverlet project code
Define database connection closure
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.PreparedStatement;
import java.sql.*;
public class DBManager {
private static final String DRIVERNAME = "com.mysql.jdbc.Driver";
private static final String URL = "jdbc:mysql://127.0.0.1:3306/bbs?useUnicode=true&characterEncoding=utf8";
private static final String USERNAME = "root";
private static final String USERPWD = "123456";
public Connection getconn() throws ClassNotFoundException, SQLException {
Class.forName(DRIVERNAME);
Connection conn=DriverManager.getConnection(URL,USERNAME,USERPWD);
System.out.print("DB Success!!");
return conn;
}
public void closeAll(ResultSet rs,PreparedStatement pstmt,Connection conn) throws SQLException {
if(rs!=null) {
rs.close();
}
if(pstmt!=null) {
pstmt.close();
}
if(conn!=null) {
conn.close();
}
}
}
Add, delete, change and search (BaseDao)
import java.sql.Connection;
import java.sql.SQLException;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
/**
*
* @author Administrator
*General method of adding, deleting and checking
*/
public class BaseDao {
public boolean insert_update_del(String sql,Object val[]) throws ClassNotFoundException, SQLException {
boolean flag=false;
Connection con=new DBManager().getconn();
PreparedStatement pstmt=con.prepareStatement(sql);
if(val!=null) {
for(int i=0;i<val.length;i++) {
pstmt.setObject(i+1, val[i]);
}
}
if(pstmt.executeUpdate()>0) {
flag=true;
}
return flag;
}
public ResultSet query(String sql,Object val[]) throws ClassNotFoundException, SQLException {
boolean flag=false;
Connection con=new DBManager().getconn();
PreparedStatement pstmt=con.prepareStatement(sql);
if(val!=null) {
for(int i=0;i<val.length;i++) {
pstmt.setObject(i+1, val[i]);
}
}
ResultSet rs=pstmt.executeQuery();
return rs;
}
}
Inherit, add, delete, modify and query
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
public class StudentsDao extends BaseDao{
public boolean regeditStudent(Student stu) throws ClassNotFoundException, SQLException {
String sql="insert into students values (null,?,?)";
Object[] val= {stu.getSname(),stu.getSpwd()};
return insert_update_del(sql,val);
}
public List<Student> quaryAll() throws ClassNotFoundException, SQLException{
List<Student> list=new ArrayList<Student>();
String sql="select * from students";
Object[] val= {};
ResultSet rs=query(sql,val);
while(rs.next()) {
Student stu=new Student();
stu.setSid(rs.getInt("sid"));
stu.setSname(rs.getString("sname"));
stu.setSpwd(rs.getString("spwd"));
list.add(stu);
}
return list;
}
public Student queryById(int sid) throws ClassNotFoundException, SQLException {
Student stu=new Student();
String sql="select * from students where sid=?";
Object[] val= {sid};
ResultSet rs=query(sql,val);
while(rs.next()) {
stu.setSid(rs.getInt("sid"));
stu.setSname(rs.getString("sname"));
stu.setSpwd(rs.getString("spwd"));
}
return stu;
}
public boolean updateStudent(Student stu) throws ClassNotFoundException, SQLException {
// Student stu=new Student();
String sql="update students set sname=?,spwd=?where sid=?";
Object[] val= {stu.getSname(),stu.getSpwd(),stu.getSid()};
if(insert_update_del(sql,val)) {
return true;
}
else {
return false;
}
}
}
RegeditServlet
import java.io.IOException;
import java.sql.SQLException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* Servlet implementation class RegeditServlet
*/
@WebServlet("/RegeditServlet")
public class RegeditServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public RegeditServlet() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
doPost(request, response);
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
// doGet(request, response);
System.out.println("Welcome……");
request.setCharacterEncoding("utf-8");
response.setCharacterEncoding("utf-8");
String sname=request.getParameter("uname");
String spwd=request.getParameter("upwd");
Student stu=new Student();
stu.setSname(sname);
stu.setSpwd(spwd);
try {
if(new StudentsDao().regeditStudent(stu)) {
// response.sendRedirect("success.jsp");
response.sendRedirect("queryAllServlet");
}else {
response.sendRedirect("error.jsp");
}
} catch (ClassNotFoundException | SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
Registration page (regedit)
<%@ page language="java" contentType="text/html; charset=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>
</head>
<body>
<h1>User registration page</h1>
<form action="regeditservlet" method="post">
<p>ursename:<input type="text" name="uname"/></p>
<p>password:<input type="password" name="upwd"/></p>
<input type="submit" value="register"/>
</form>
</body>
</html>
Error page
<%@ page language="java" contentType="text/html; charset=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>
</head>
<body>
<h1>Failed to register</h1>
</body>
</html>
web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/Demo4.xsd" id="WebApp_ID" version="3.1">
<display-name>Demo4</display-name>
<welcome-file-list>
<welcome-file>index.html</welcome-file>
<welcome-file>index.htm</welcome-file>
<welcome-file>index.jsp</welcome-file>
<welcome-file>default.html</welcome-file>
<welcome-file>default.htm</welcome-file>
<welcome-file>default.jsp</welcome-file>
</welcome-file-list>
<servlet>
<servlet-name>regeditservlet</servlet-name>
<servlet-class>aaa.com.RegeditServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>regeditservlet</servlet-name>
<url-pattern>/regeditservlet</url-pattern>
</servlet-mapping>
<!--Add additional content here -->
</web-app>
EditServlet
import java.io.IOException;
import java.sql.SQLException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* Servlet implementation class EditServlet
*/
@WebServlet("/EditServlet")
public class EditServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public EditServlet() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
doPost(request, response);
// response.getWriter().append("Served at: ").append(request.getContextPath());
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
// doGet(request, response);
request.setCharacterEncoding("utf-8");
response.setCharacterEncoding("utf-8");
try {
int sid=Integer.parseInt(request.getParameter("uid"));
String sname=request.getParameter("uname");
System.out.println(sname);
String spwd=request.getParameter("upwd");
System.out.println(spwd);
Student stu=new Student();
stu.setSid(sid);
stu.setSname(sname);
stu.setSpwd(spwd);
if(new StudentsDao().updateStudent(stu)) {
response.sendRedirect("queryallservlet");
}else {
response.sendRedirect("error.jsp");
}
} catch (ClassNotFoundException | SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
QueryAllServlet
import java.io.IOException;
import java.sql.SQLException;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* Servlet implementation class QueryAllServlet
*/
@WebServlet("/queryAllServlet")
public class QueryAllServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public QueryAllServlet() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
doPost(request, response);
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
request.setCharacterEncoding("utf-8");
response.setCharacterEncoding("utf-8");
try {
List<Student> list=new StudentsDao().quaryAll();
request.setAttribute("list", list);
request.getRequestDispatcher("show.jsp").forward(request, response);
} catch (ClassNotFoundException | SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
Show page
<%@ page language="java" contentType="text/html; charset=utf-8"
%>
<%@ page import="java.util.*" %>
<%@ 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>
<h1>User Information Details</h1>
<table>
<tr>
<td>num</td>
<td>name</td>
<td>password</td>
<td>Operation</td>
<tr>
<c:forEach var="stu" items="${list}" step="1">
<tr>
<td>${stu.sid}</td>
<td>${stu.sname}</td>
<td>${stu.spwd}</td>
<td><a href="updateservlet?sid=${stu.sid}">修改</a>|<a href="delserverlet?sid=${stu.sid}">删除</a></td>
<tr>
</c:forEach>
</table>
</body>
</html>
web.xml
<servlet>
<servlet-name>editservlet</servlet-name>
<servlet-class>aaa.com.EditServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>editservlet</servlet-name>
<url-pattern>/editservlet</url-pattern>
</servlet-mapping>
web.xml
<servlet>
<servlet-name>queryallservlet</servlet-name>
<servlet-class>aaa.com.QueryAllServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>queryallservlet</servlet-name>
<url-pattern>/queryallservlet</url-pattern>
</servlet-mapping>
UpdateServlet
import java.io.IOException;
import java.sql.SQLException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* Servlet implementation class UpdateServlet
*/
@WebServlet("/updateServlet")
public class UpdateServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public UpdateServlet() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
// response.getWriter().append("Served at: ").append(request.getContextPath());
doPost(request, response);
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
request.setCharacterEncoding("utf-8");
response.setCharacterEncoding("utf-8");
int sid=Integer.parseInt(request.getParameter("sid"));
System.out.println(sid);
Student stu=new Student();
try {
stu=new StudentsDao().queryById(sid);
request.setAttribute("stu", stu);
request.getRequestDispatcher("update.jsp").forward(request, response);
// System.out.println(stu.sid);
} catch (ClassNotFoundException | SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
Modify page
<%@ page language="java" contentType="text/html; charset=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>
</head>
<body>
<h1>user update</h1>
<form action="editservlet" method="post">
<p>number:<input type="text" name="uid" readonly="readonly" value="${stu.sid}"/></p>
<p>username:<input type="text" name="uname" value="${stu.sname}"/></p>
<p>password:<input type="password" name="upwd" value="${stu.spwd}"/></p>
<input type="submit" value="modify"/>
</form>
</body>
</html>
web.xml
<servlet>
<servlet-name>updateservlet</servlet-name>
<servlet-class>aaa.com.UpdateServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>updateservlet</servlet-name>
<url-pattern>/updateservlet</url-pattern>
</servlet-mapping>
SubServer
import java.io.IOException;
import java.sql.SQLException;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* Servlet implementation class DeleteServlet
*/
@WebServlet("/DeleteServlet")
public class DeleteServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public DeleteServlet() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
// response.getWriter().append("Served at: ").append(request.getContextPath());
doPost(request, response);
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
request.setCharacterEncoding("utf-8");
response.setCharacterEncoding("utf-8");
int sid = Integer.parseInt(request.getParameter("sid"));
Student stu=new Student();
stu.setSid(sid);
try {
if(new StudentsDao().deleteStudent(sid)) {
response.sendRedirect("queryAllServlet");
}else {
response.sendRedirect("error.jsp");
}
} catch (ClassNotFoundException | SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
web.xml
<servlet>
<servlet-name> delserverlet</servlet-name>
<servlet-class>aaa.com.DelServerlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>delserverlet</servlet-name>
<url-pattern>/delserverlet</url-pattern>
</servlet-mapping>
