下面的结构图
1.在src你创建com.hqyj.wj.model建立model包,model里放数据库的元素,User.java的截图
package com.hqyj.wj.model;
//用户信息表
public class User {
private int id;
private String name;
private String birthday;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getBirthday() {
return birthday;
}
public void setBirthday(String birthday) {
this.birthday = birthday;
}
}
2.在src你创建com.hqyj.wj.dao.inf建立包,这个包是放接口类,这是UserDaoInf的截图
package com.hqyj.wj.dao.inf;
import java.util.List;
import com.hqyj.wj.model.User;
/**
* 数据访问层的接口定义数据接口的方法
*
*/
public interface UserDaoInf {
//定义一个查询方法
List<User> search();
}
3.在src你创建com.hqyj.wj.dao建立包,这个包连接数据库,及实现上面的接口类
package com.hqyj.wj.dao;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.List;
import com.hqyj.wj.dao.inf.UserDaoInf;
import com.hqyj.wj.model.User;
/**
*
* @author wl 数据访问接口
*/
public class UserDao implements UserDaoInf {
// 数据访问数据库的连接对象
protected Connection con = null;
// 获取数据库链接
@SuppressWarnings("finally")
public Connection getCon() {
try {
// 加载mysql驱动
Class.forName("com.mysql.jdbc.Driver");
//获取数据库链接
con=DriverManager.getConnection("jdbc:mysql://127.0.0.1:3306/image?characterEncoding=utf8", "root", "root");
System.out.println("链接成功");
return con;
} catch (Exception e) {
System.out.println("链接失败"+e.getMessage());
return null;
} finally {
try {
con.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}
}
public List<User> search() {
return null;
}
}
4.在src你创建com.hqyj.wj.controller建立包,里面放的new->servlet
package com.hqyj.wj.controller;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class OneServlet extends HttpServlet {
public OneServlet() {
super();
}
public void destroy() {
super.destroy(); // Just puts "destroy" string in log
// Put your code here
}
//doget对应的是ajax的$.get()方法
//request是装载请求数据
//response响应数据到前端对象
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//解决中文乱码的问题
request.setCharacterEncoding("utf-8");
response.setCharacterEncoding("utf-8");
//在服务器端设置允许在其他域名下访问，及响应类型、响应头设置
System.out.println("这是");
response.setHeader("Access-Control-Allow-Origin", "*");
response.setHeader("Access-Control-Allow-Methods","POST");
response.setHeader("Access-Control-Allow-Headers","x-requested-with,content-type");
//响应的文本格式
response.setContentType("text/html");
//获取响应的输出对象
PrintWriter out = response.getWriter();
out.print("nissssss");
out.print("您好呀");
out.flush();
out.close();
}
//doget对应的是ajax的$.post()方法
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html");
PrintWriter out = response.getWriter();
out.println("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\">");
out.println("<HTML>");
out.println(" <HEAD><TITLE>A Servlet</TITLE></HEAD>");
out.println(" <BODY>");
out.print(" This is ");
out.print(this.getClass());
out.println(", using the POST method");
out.println(" </BODY>");
out.println("</HTML>");
out.flush();
out.close();
}
/**
* Initialization of the servlet. <br>
*
* @throws ServletException if an error occurs
*/
public void init() throws ServletException {
// Put your code here
}
}
5.要引入数据库包mysql-connector-java-commercial-5.1.25-bin.jar,在项目名字上右键->properties->java Build Path->Libraries->Add External Jars然后选择你下载的包
6.在src下面创建测试类
import com.hqyj.wj.dao.UserDao;
public class Test {
public static void main(String[] args) {
//获取数据库访问类对象
UserDao dao=new UserDao();
dao.getCon();
}
}
7.成功显示
时间： 2024-11-10 01:28:04