Day 09 学生管理（增删改查）

1.Dao.java

//连接数据库

package com.stu.tab;

import java.sql.*;

public class Dao {
private static Connection connection;//定义一个静态连接类型对象
public static Connection getConn(){
try {
Class.forName("com.mysql.jdbc.Driver");//加载驱动
connection=DriverManager.getConnection("jdbc:mysql://localhost:3306/studb","root","12345678");//得到数据库链接对象并且给connection赋值
} catch (Exception e) {
e.printStackTrace();
}
return connection;

}

public static void closeAll(ResultSet res,PreparedStatement smt,Connection conn){
try{
if(res!=null){
res.close();
}
if(smt!=null){
smt.close();
}
if(conn!=null){
conn.close();
}
}catch(Exception e){

}
}

}


2.Student.java
//定义Student类型

package com.stu.tab;

public class Student {
private Integer id;
private String stuname;
private String stuage;
private String stusex; //javabean

//private不能被外部直接访问，每个属性都有一个get和set方法用来读取或设置私有属性的值
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getStuname() {
return stuname;
}
public void setStuname(String stuname) {
this.stuname = stuname;
}
public String getStuage() {
return stuage;
}
public void setStuage(String stuage) {
this.stuage = stuage;
}
public String getStusex() {
return stusex;
}
public void setStusex(String stusex) {
this.stusex = stusex;
}
public Student(Integer id, String stuname, String stuage, String stusex) {//构造方法：实例化对象时直接赋值
super();
this.id = id;
this.stuname = stuname;
this.stuage = stuage;
this.stusex = stusex;
}
public Student(){

}

}


3.StudentDao()
package com.stu.test;

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

public class StudentDao {

private Connection conn;
private List<Student> stus;
private PreparedStatement smt;
private ResultSet rs;
public List<Student> getAll(){

try {
stus=new ArrayList<Student>();
conn= Dao.getconn();
smt=conn.prepareStatement("select * from stu_tab");
rs=smt.executeQuery();
while(rs.next()){
Student student=new Student(rs.getInt("id"),rs.getString("stuname"),rs.getString("stuage"),rs.getString("stusex"));
stus.add(student);
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
new Dao().closeAll(rs, smt, conn);
}
return stus;

}

public void delete(int id){
try {
conn= Dao.getconn();
smt=conn.prepareStatement("delete from stu_tab where id=?");
smt.setInt(1, id);
smt.execute();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
new Dao().closeAll(rs, smt, conn);
}
}

public void insert(Student student){
try {
conn= Dao.getconn();
smt=conn.prepareStatement("insert into stu_tab (stuname,stuage,stusex)values(?,?,?)");
smt.setString(1, student.getStuname());
smt.setString(2, student.getStuage());
smt.setString(3, student.getStusex());
smt.execute();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
new Dao().closeAll(rs, smt, conn);

}
}
public Student ById(Integer id){
Student val = null;
try {
conn=Dao.getconn();
smt=conn.prepareStatement("select * from stu_tab where id=?");
smt.setInt(1, id);
rs=smt.executeQuery();

while(rs.next()){
ab3d
val=new Student(rs.getInt("id"),rs.getString("stuname"),rs.getString("stuage"),rs.getString("stusex"));
}

} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
new Dao().closeAll(rs, smt, conn);

}
return val;
}
public void update(Student stu){
try {
conn= Dao.getconn();
smt=conn.prepareStatement("update stu_tab set stuname=?,stuage=?,stusex=? where id=?");
smt.setString(1, stu.getStuname());
smt.setString(2, stu.getStuage());
smt.setString(3, stu.getStusex());
smt.setInt(4,stu.getId());
smt.execute();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
new Dao().closeAll(rs, smt, conn);

}
}
}


4.StudentServlet.java

package com.stu.test;

import java.io.IOException;
import java.util.ArrayList;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@WebServlet("/studentservlet")
public class StudentServlet extends HttpServlet {
private static final long serialVersionUID = 1L;

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doPost(request, response);
}

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String method=request.getParameter("method");
if(method.equals("all")){
this.all(request, response);
}
if(method.equals("delete")){
this.delete(request,response);
}
if(method.equals("insert")){
this.insert(request,response);
}
if(method.equals("update1")){
this.update1(request,response);
}
if(method.equals("update2")){
this.update2(request,response);
}
}

private void update2(HttpServletRequest request,
HttpServletResponse response) throws IOException {
Integer id=Integer.parseInt(request.getParameter("id"));
String stuname=request.getParameter("stuname");
String stuage=request.getParameter("stuage");
String stusex=request.getParameter("stusex");
new StudentDao().update(new Student(id,stuname,stuage,stusex));
response.sendRedirect("studentservlet?method=all");
}

private void update1(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
Integer id=Integer.parseInt(request.getParameter("id"));
Student stu=new StudentDao().ById(id);
request.setAttribute("stus", stu);
request.getRequestDispatcher("/update.jsp").forward(request, response);
}

private void delete(HttpServletRequest request, HttpServletResponse response) throws IOException {
Integer id=Integer.parseInt(request.getParameter("id"));//从show页面接收id的值
new StudentDao().delete(id);
response.sendRedirect("studentservlet?method=all");
}

public void all(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException{
ArrayList al=(ArrayList) new StudentDao().getAll();//调用getall()方法
request.setAttribute("all",al);//将值放入Request
request.getRequestDispatcher("/show.jsp").forward(request, response);//请求转发到指定页面
}
public void insert(HttpServletRequest request, HttpServletResponse response) throws IOException{
String stuname=request.getParameter("stuname");
String stuage=request.getParameter("stuage");
String stusex=request.getParameter("stusex");
new StudentDao().insert(new Student(0,stuname,stuage,stusex));
response.sendRedirect("studentservlet?method=all");
}

}


5.show.jsp
<%@page import="com.stu.test.Student"%>
<%@page import="java.util.ArrayList"%>
<%@ 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>
</head>
<body>
<%
ArrayList<Student> list=(ArrayList<Student>)request.getAttribute("all");//
%>
<h1><a href="insert.jsp">insert</a></h1>
<table border=1>
<tr>
<td>id</td>
<td>username</td>
<td>userage</td>
<td>usersex</td>
<td>操作</td>
</tr>

<%for(Student lists:list){%>
<tr>
<td><%=lists.getId()%></td>
<td><%=lists.getStuname()%></td>
<td><%=lists.getStuage()%></td>
<td><%=lists.getStusex()%></td>
<td>
<a href="studentservlet?method=delete&id=<%=lists.getId()%>">删除</a> 
<a href="studentservlet?method=update1&id=<%=lists.getId()%>">修改</a>
</td>
</tr>
<%} %>
</table>
</body>
</html>

6.insert.jsp

<!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 method="post" action="studentservlet?method=insert">
stuname:<input type="text" name="stuname" ><br>
stuname:<input type="text" name="stuage" ><br>
stuname:<input type="text" name="stusex" ><br>
<input type="submit" name="sub" value="tijiao">
</form>

</body>
</html>

7.updata.jsp

<%@page import="com.stu.test.Student"%>
<%@ 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>
</head>
<body>
<%Student val=(Student)request.getAttribute("stus"); %>
<form method="post" action="studentservlet?method=update2">
<input type="hidden" name="id" value=<%=val.getId() %> >
stuname:<input type="text" name="stuname" value=<%=val.getStuname() %>><br>
stuname:<input type="text" name="stuage" value=<%=val.getStuage() %>><br>
stuname:<input type="text" name="stusex" value=<%=val.getStusex() %>><br>
<input type="submit" name="sub" value="tijiao">
</form>

</body>
</html>

8.index.jsp
<%@ 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>
</head>
<body>
<a href="studentservlet?method=all">show</a>
</body>
</html>