【複習】servlet之ConnectionDataBase

1，首先數據庫要有數據，所以要創建數據庫，數據表，插入數據
數據表結構：

2，插入數據：

3，導入jar包

4，代碼如下：
package com.databse;

import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

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

public class ConnectionDataBaseTest extends HttpServlet {
/**
*
*/
private static final long serialVersionUID = 1L;

@Override
public void init() throws ServletException {
    // TODO Auto-generated method stub
    super.init();
}

@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    String JDBCDRIVER = "com.mysql.jdbc.Driver";
    String JDBCURI = "jdbc:mysql://localhost:3306/test_db";
    String USERNAME="root";
    String PASSWORD="";
    //響應內容類型
    response.setContentType("text/html");
    response.setCharacterEncoding("utf-8");
    PrintWriter out=response.getWriter();
    //註冊JDBC Driver
    Connection conn=null;
    PreparedStatement stamt=null;
    ResultSet rs=null;
    try{
        Class.forName(JDBCDRIVER);
        conn=DriverManager.getConnection(JDBCURI, USERNAME, PASSWORD);
        String sql="select * from tab_test";
        stamt=conn.prepareStatement(sql);
        rs=stamt.executeQuery();
        while(rs.next()){
            int id=rs.getInt("id");
            String name=rs.getString("name");
            System.out.println(id+":"+name);
            out.println(id);
            out.println(name);
        }
        rs.close();
        stamt.close();
        conn.close();
    }catch(Exception e){
        e.printStackTrace();
    }finally {
        if(conn!=null){
            try {
                conn.close();
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
    }

}

@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    // TODO Auto-generated method stub
    super.doPost(req, resp);
}

@Override
public void destroy() {
    // TODO Auto-generated method stub
    super.destroy();
}

}

5,配置web.xml文件

<!--主要配置文件 -->
    <servlet>
        <servlet-name>database</servlet-name>
        <servlet-class>com.databse.ConnectionDataBaseTest</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>database</servlet-name>
        <url-pattern>/ConnectionDataBaseTest</url-pattern>
    </servlet-mapping>

6，查看瀏覽器和Console