- 1、写数据库
- 2、在pojo中写一个方法
- 3、操作实现
- 3.1在servelet中写一个相应的servlet方法
- 3.2删除的相关代码
- 3.3增加的相关代码servlet
- 3.4、编辑的相关代码
定义get，set，construct，tostring等方法
package com.situ.web.pojo;
public class Teacher {
private Integer id;
private String name;
private Integer age;
public Teacher() {
}
public Teacher(Integer id, String name, Integer age, String address) {
this.id = id;
this.name = name;
this.age = age;
this.address = address;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
private String address;
@Override
public String toString() {
return "Teacher{" +
"id=" + id +
", name='" + name + ''' +
", age=" + age +
", address='" + address + ''' +
'}';
}
}
3、操作实现
3.1在servelet中写一个相应的servlet方法
注意的是要进行继承httpservlet，写@webservlet ，并进行重写
为了保证输入的时候不会造成乱码，要在service 的首句加上req.setCharacterEncoding(“UTF-8”);
首先是实现了查询，也就是页面显示的代码
@WebServlet("/teacher")
public class TeacherServlet extends HttpServlet {
@Override
protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
req.setCharacterEncoding("UTF-8");
System.out.println("TeacherServlet.service");
String method =req.getParameter("method");
if(method==null||method.equals("")){
method="selectAll";
} //这个是为了让他直接显示这个页面用的
switch (method){
case "selectAll":
select(req,resp);
break;
}
}
private void select(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
Connection connection = null;
PreparedStatement statement =null;
ResultSet resultSet =null;
List list=new ArrayList<>();
try {
connection= JDBCUtil.getConnection();
String sql = "select id,name,age,address from teacher";
statement=connection.prepareStatement(sql);
System.out.println(statement);
resultSet = statement.executeQuery();
while(resultSet.next()){
int id=resultSet.getInt("id");
String name = resultSet.getString("name");
int age = resultSet.getInt("age");
String address = resultSet.getString("address");
Teacher teacher = new Teacher(id,name,age,address);
list.add(teacher);
}
} catch (SQLException throwables) {
throwables.printStackTrace();
}finally {
JDBCUtil.close(connection,statement,null);
}
//把list集合的数据放到request内存中
req.setAttribute("list",list);
//转发到studen_list.jsp页面进行展示
req.getRequestDispatcher("teacher_list.jsp").forward(req,resp);
}
}
3.2删除的相关代码
servlet中：
private void delete(HttpServletRequest req, HttpServletResponse resp) throws IOException {
String id = req.getParameter("id");
Connection connection=null;
PreparedStatement statement = null;
try {
connection= JDBCUtil.getConnection();
String sql="delete from teacher where id=?";
statement = connection.prepareStatement(sql);
statement.setInt(1,Integer.parseInt(id));
System.out.println(statement);
int cout=statement.executeUpdate();
System.out.println(cout);
} catch (SQLException throwables) {
throwables.printStackTrace();
}finally {
JDBCUtil.close(connection,statement,null);
}
resp.sendRedirect(req.getContextPath()+"/teacher?method=selectAll"); //重定向，返回列表
}
teacher_list.jsp中
| ID | 姓名 | 年纪 | 地址 | 删除 | 修改 |
| <%=teacher.getId()%> | <%=teacher.getName()%> | <%=teacher.getAge()%> | <%=teacher.getAddress()%> | 删除 | 修改 |
private void add(HttpServletRequest req, HttpServletResponse resp) throws IOException {
System.out.println("TeacherServlet.add");
String name = req.getParameter("name");
String age =req.getParameter("age");
String address = req.getParameter("address");
Connection connection =null;
PreparedStatement statement = null;
try {
connection = JDBCUtil.getConnection();
String sql = "insert into teacher(name,age,address)value(?,?,?)";
statement=connection.prepareStatement(sql);
statement.setString(1,name);
statement.setInt(2,Integer.parseInt(age));
statement.setString(3,address);
System.out.println(statement);
int cout=statement.executeUpdate();
System.out.println(cout);
} catch (SQLException throwables) {
throwables.printStackTrace();
}finally {
JDBCUtil.close(connection,statement,null);
}
resp.sendRedirect(req.getContextPath()+"/teacher?method=selectAll");
}
teacher_add.jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
Title
