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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