使用 servlet 连接数据库-白红宇

使用 servlet 连接数据库

阅读量：6717 次

发布时间：2019-06-25

本文共 5179 字，大约阅读时间需要 17 分钟。

1.项目工程 web.xml 配置

1 
     
        2     
      
       This is the description of my J2EE component
        3     
      
       This is the display name of my J2EE component
        4     
      
       DBServlet
        5     
      
       org.olive.DBServlet
        6     
      
         7             
       
        driverName
         8             
       
        com.microsoft.jdbc.sqlserver.SQLServerDriver
         9         
       10         
      
        11         
       
        username
                   12             
       
        sa
                       13         
       14         
      
        15             
       
        password
               16             
                       17         
       18         
      
        19             
       
        dbName
           20             
       
        pubs
           21         
       22 23

1 
     
       2     
      
       DBServlet
       3     
      
       /servlet/DBServlet
       4

2.servlet java文件

DBServlet.java

1 package org.olive;  2  3 import java.io.*;                                    //导入java.io包  4 import java.util.*;  5 import java.sql.*;  6 import javax.servlet.*;  7 import javax.servlet.http.*;  8 public class DBServlet extends HttpServlet{            //定义一个继承HttpServlet的公有类  9     ServletConfig config=null;                        //定义一个ServletConfig对象 10     private String driverName="";                    //定义私有字符串常量并初始化 11     private String username="";                    //定义的数据库用户名 12     private String password="";                    //定义的数据库连接密码 13     private String dbName="";                        //定义的数据库名 14     private Connection conn;                        //初始化连接 15     private Statement stmt;                        //初始化数据库操作 16     ResultSet rs=null;                            //初始化结果集 17     public void init(ServletConfig config)throws ServletException{
    18      super.init(config);                            //继承父类的init()方法 19      this.config=config;                            //获取配置信息 20      driverName=config.getInitParameter("driverName");//从配置文件中获取JDBC驱动名 21      username=config.getInitParameter("username");    //获取数据库用户名 22       password=config.getInitParameter("password");    //获取数据库连接密码 23       dbName=config.getInitParameter("dbName");    //获取要连接的数据库 24         } 25     public void doGet(HttpServletRequest req,HttpServletResponse resp)throws IOException,ServletException{
    26        27         resp.setContentType("text/html;charset=GBK");    //设置字符编码格式 28         PrintWriter out=resp.getWriter();                //实例化对象，用于页面输出 29           out.println("");                    //实现生成静态Html 30           out.println(""); 31           out.println("
      "); 32           out.println("DataBase Connection"); 33           out.println(""); 34           out.println(""); 35           out.println("
      
       "); 36           String url="jdbc:microsoft:sqlserver://localhost:1433; DatabaseName=pubs"; 37           try{
    38                 Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver"); 39                 conn=DriverManager.getConnection(url,username,password); 40                 stmt=conn.createStatement(); 41                 String sql="use pubs select * from publishers"; 42                 rs=stmt.executeQuery(sql); 43                   out.println("Servlet访问数据库成功"); 44                   out.println("
       
        "); 45                   out.println("
"); 46                   out.println("
"); 47                   out.println("
"); 48                   out.println("
"); 49                   out.println("
"); 50                    while(rs.next()){
    51                     out.println("
"); 52                     out.println("
"); 53                     out.println("
"); 54                     out.println("
"); 55                     out.println("
"); 56                     out.println("
          "); 57                    } 58                    out.println("
                           序号           书名           城市           州           国          
                   "+rs.getString(1)+"           "+rs.getString(2)+"           "+rs.getString(3)+"           "+rs.getString(4)+"           "+rs.getString(5)+"          
                  
        
       
"); 59                    rs.close(); 60                    stmt.close(); 61                    conn.close();    62                   63               }catch(Exception e){
    64               e.printStackTrace(); 65               out.println(e.toString());    66               } 67               out.println("
      "); 68           out.println(""); 69           out.println(""); 70            } 71            public void doPost(HttpServletRequest req,HttpServletResponse resp)throws IOException,ServletException{
    72                this.doGet(req,resp); 73                } 74                public void destory(){
    75                    config=null; 76                    driverName=null; 77                    username=null; 78                    password=null; 79                    dbName=null; 80                    conn=null; 81                    stmt=null; 82                    rs=null; 83                    } 84 }