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servlet连接mysql小程序

时间:2021-07-01 10:21:17 帮助过:20人阅读

import javax.servlet.http.HttpServlet; 2 import javax.servlet.http.HttpServlet;import java.io.IOException; 3 import java.io.*; 4 import javax.servlet.http.HttpServletRequest; 5 import javax.servlet.http.HttpServletResponse; 6 public class httpservlet extends HttpServlet { 7 8 protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws IOException{ 9 PrintWriter out =resp.getWriter(); 10 out.println("<html><head><head/><body><h1>hello<h1><body/><html/>"); 11 out.flush(); 12 out.close(); 13 } 14 15 16 17 18 19 20 }

3.先想一下为什么跟数据库连接,数据库连接的部分添在哪里.

跟数据库是在服务器端输出结果之前需要做的事情,就是out.printn那一段。我们需要调取数据库中的数据,再进行决策,然后输出请求结果。

4.编译代码

 1 import java.sql.Connection;
 2 import java.sql.DriverManager;
 3 import java.sql.SQLException;
 4 import java.util.Properties;
 5 import javax.servlet.http.HttpServlet;
 6 import javax.servlet.http.HttpServlet;import java.io.IOException;
 7 import java.io.*;
 8 import javax.servlet.http.HttpServletRequest;
 9 import javax.servlet.http.HttpServletResponse;
10 public class ServletMysql extends HttpServlet {
11 
12  protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws IOException{
13     
14     try {
15             // The newInstance() call is a work around for some
16             // broken Java implementations
17 
18             Class.forName("com.mysql.jdbc.Driver").newInstance();
19              System.out.println("heo");
20             Connection conn = 
21        DriverManager.getConnection("jdbc:mysql://localhost/test?" + 
22                                    "user=root&password=root");
23 
24 
25        
26      
27      
28      
29      System.out.println(conn);
30       PrintWriter out =resp.getWriter();
31       out.println("<html><head><head/><body><h1>hello<h1><body/><html/>");
32       out.flush();
33       out.close();
34               
35         } catch (Exception ex) {
36             // handle the error
37         }
38 
39 
40 
41 
42 
43 
44     
45 }

 

5.将servlet小程序class文件放入tomcat容器中(见我的博客,基于servlet编程)

6,如何在输入框中输入什么,能让tomcat执行我们的servletmysql的calss文件呢,那就是web.xml的配置了

<servlet>
      <servlet-name>twoservlet</servlet-name>
      <servlet-class>ServletMysql</servlet-class>
    </servlet>


<servlet-mapping>
        <servlet-name>twoservlet</servlet-name>
        <url-pattern>/mysql</url-pattern>
    </servlet-mapping>

7.根据自己的项目设置,输入正确的地址(我的是http://127.0.0.1:8080/myweb/mysql)

8.结果(在服务器端输出连接的信息,说明数据库连接成功)

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servlet连接mysql小程序

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