[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