What Mybatis that?

MyBatis this is apache an open source project iBatis , 2010 Nian this project by the apache software foundation moved to Google code , and changed its name to MyBatis , essentially Mybatis to ibatis some improvements.

MyBatis is an excellent persistence framework, the process of its operation jdbc database encapsulation, so that developers only need to focus on SQL itself , without the need to spend energy to processing such as registration drive, create a connection, create a statement, manually set the parameters, retrieval result set jdbc complicated procedure code .

Various statement (statement, preparedStatemnt, CallableStatement) Mybatis xml or annotation by way arranged to be performed together, and the final map generation sql statement executed by a java object and the sql statement, sql and executed by the Last frame mybatis mapped into java objects and return.

1. Analysis of the original eco-jdbc program Problems
   1. The original ecology J DBC program code

      
      public static void main(String[] args) {
      
      Connection connection = null;
      
      PreparedStatement preparedStatement = null;
      
      ResultSet resultSet = null;
      
      
      try {
      
      //1、加载数据库驱动
      
      Class.forName("com.mysql.jdbc.Driver");
      
      //2、通过驱动管理类获取数据库链接
      
      connection =  DriverManager.getConnection("jdbc:mysql://localhost:3306/mybatis?characterEncoding=utf-8", "root", "root");
      
      //3、定义sql语句 ?表示占位符
      
      String sql = "select * from user where username = ?";
      
      //4、获取预处理statement
      
      preparedStatement = connection.prepareStatement(sql);
      
      //5、设置参数，第一个参数为sql语句中参数的序号（从1开始），第二个参数为设置的参数值
      
      preparedStatement.setString(1, "王五");
      
      //6、向数据库发出sql执行查询，查询出结果集
      
      resultSet =  preparedStatement.executeQuery();
      
      //7、遍历查询结果集
      
      while(resultSet.next()){
      
      System.out.println(resultSet.getString("id")+"  "+resultSet.getString("username"));
      
      }
      
      } catch (Exception e) {
      
      e.printStackTrace();
      
      }finally{
      
      //8、释放资源
      
      if(resultSet!=null){
      
      try {
      
      resultSet.close();
      
      } catch (SQLException e) {
      
      // TODO Auto-generated catch block
      
      e.printStackTrace();
      
      }
      
      }
      
      if(preparedStatement!=null){
      
      try {
      
      preparedStatement.close();
      
      } catch (SQLException e) {
      
      // TODO Auto-generated catch block
      
      e.printStackTrace();
      
      }
      
      }
      
      if(connection!=null){
      
      try {
      
      connection.close();
      
      } catch (SQLException e) {
      
      // TODO Auto-generated catch block
      
      e.printStackTrace();
      
      }
      
      }
      
      }
      
      }

2. 1. J DBC problem summary
3. Frequent opening and closing the database connection, it will seriously affect the performance of the database.
4. Hard-coded code is present, it is hard-coded portions and hard-coded database SQL execution section.