[JavaWeb基础] 003.JAVA访问Mysql数据库

　　上面两篇讲解了简单的JSP + Servlet的搭建和请求，那么后面我们肯定要用到数据交互，也就是操纵数据库的数据，包括对数字的增加，删除，修改，查询。我们就用简单的MySql来做例子

我们需要引入驱动包mysql-connector-java.jar，自行去网上下载，有很多。

下面我跟着代码看看怎么进行增删改查

1.打开数据库

    // 驱动程序名

    private String driver   = "com.mysql.jdbc.Driver";

    // URL指向要访问的数据库名scutcs

    private String url      = "jdbc:mysql://127.0.0.1:3306/studentdb";

    // MySQL配置时的用户名

    private String user     = "root"; 

    // MySQL配置时的密码

    private String password = "root";



    private static Connection conn = null; 



    /**

     * 打开数据连接

     */

    public void openDbConnect()

    {

        try 

        { 

	         // 加载驱动程序

	         Class.forName(driver);

	         // 连接数据库

	         if(conn == null || conn.isClosed())

	         {

	        	 conn = DriverManager.getConnection(url, user, password);

	         }

	         if(!conn.isClosed()) 

	         {

	        	 System.out.println("Succeeded connecting to the Database!");

	         }

        }

        catch(Exception ex)

        {

        	System.out.println("访问数据库失败");

        }

    }

 2.增加数据

    /**

     * 插入数据

     * @param student

     * @throws SQLException 

     */

    public void insertStudent(Student student) throws SQLException

    {

    	 Statement statement = conn.createStatement();

         // 要执行的SQL语句

         String sql = "insert into student (studentname,age,classname) values('" 
                      + student.getStudentname() + " '," 
                      + student.getAge() + ",'" + student.getClassname() + "')";

         statement.execute(sql);

    }

 3.删除数据

    /**

     * 删除数据

     * @param student

     * @throws SQLException 

     */

    public void deleteStudent(int id) throws SQLException

    {

    	 Statement statement = conn.createStatement();

         // 要执行的SQL语句

         String sql = "delete from student where id = " + id;

         statement.execute(sql);

    }

 4.更新数据

 /**

     * 修改数据

     * @param student

     * @throws SQLException 

     */

    public void updateStudent(Student student) throws SQLException

    {

    	 Statement statement = conn.createStatement();

         // 要执行的SQL语句

         String sql = "update student set ";

         // 学生名称

         if(student.getStudentname() != null && !student.getStudentname().trim().equals("") )

         {

        	 sql += " studentname = '" + student.getStudentname() + "',";

         }

         // 年龄

         if(student.getAge() != 0 )

         {

        	 sql += " age = " + student.getAge() + ",";

         }

         // 年级

         if(student.getClassname() != null && !student.getClassname().trim().equals("") )

         {

        	 sql += " classname = '" + student.getClassname() + "',";

         }

         sql = sql.substring(0, sql.length() - 1);

         sql = sql + " where id = " + student.getId();

         statement.execute(sql);

    }

    

 5.查询数据

    /**

     * 修改数据

     * @param student

     * @throws SQLException 

     */

    public void queryStudent(String studentname) throws SQLException

    {

    	 Statement statement = conn.createStatement();

         // 要执行的SQL语句

         String sql = "select * from student where  studentname = '" + studentname + "'";

         ResultSet rs = statement.executeQuery(sql);

         while(rs.next()) {

             // 选择sname这列数据

             String studentnamers = rs.getString("studentname");

             String agers         = rs.getString("age");

             String classnamers   = rs.getString("classname");

             // 输出结果

             System.out.println("学生名称:" + studentnamers + ",年龄:" + agers  + ",班级:" + classnamers);

        }

    }

以上介绍了JAVA访问Mysql的简单代码，比较深入的后面我们再讲解。本篇文章只是带大家简单入门

 

结语

• 受益，学会了如何用JAVA访问Mysql数据库

 

 

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转载自【宝宝巴士SuperDo团队】 原文链接: http://www.cnblogs.com/superdo/p/4561918.html