📜  iBATIS-结果图

📅  最后修改于: 2020-11-16 08:15:00             🧑  作者: Mango


resultMap元素是iBATIS中最重要和功能最强大的元素。您可以使用iBATIS ResultMap减少多达90%的JDBC编码,在某些情况下,它允许您执行JDBC甚至不支持的操作。

ResultMaps的设计使得简单的语句根本不需要显式的结果映射,而更复杂的语句所需要的仅比描述关系绝对必要。

本章仅提供iBATIS ResultMap的简单介绍。

我们在MySQL中有以下EMPLOYEE表-

CREATE TABLE EMPLOYEE (
   id INT NOT NULL auto_increment,
   first_name VARCHAR(20) default NULL,
   last_name  VARCHAR(20) default NULL,
   salary     INT  default NULL,
   PRIMARY KEY (id)
);

该表具有两个记录,如下所示:

mysql> select * from EMPLOYEE;
+----+------------+-----------+--------+
| id | first_name | last_name | salary |
+----+------------+-----------+--------+
|  1 | Zara       | Ali       |   5000 |
|  2 | Roma       | Ali       |   3000 |
+----+------------+-----------+--------+
2 row in set (0.00 sec)

员工POJO班

要使用iBATIS ResultMap,您不需要修改Employee.java文件。让我们保持上一章的样子。

public class Employee {
   private int id;
   private String first_name; 
   private String last_name;   
   private int salary;  

   /* Define constructors for the Employee class. */
   public Employee() {}
  
   public Employee(String fname, String lname, int salary) {
      this.first_name = fname;
      this.last_name = lname;
      this.salary = salary;
   }

   /* Here are the required method definitions */
   public int getId() {
      return id;
   }
    
   public void setId(int id) {
      this.id = id;
   }
    
   public String getFirstName() {
      return first_name;
   }
    
   public void setFirstName(String fname) {
      this.first_name = fname;
   }
    
   public String getLastName() {
      return last_name;
   }
    
   public void setlastName(String lname) {
      this.last_name = lname;
   }
    
   public int getSalary() {
      return salary;
   }
    
   public void setSalary(int salary) {
      this.salary = salary;
   }

} /* End of Employee */

Employee.xml文件

在这里,我们将修改Employee.xml以引入 标记。该标签将具有在 SELECT * FROM EMPLOYEE UPDATE EMPLOYEE SET first_name = #first_name# WHERE id = #id# DELETE FROM EMPLOYEE WHERE id = #id#

IbatisResultMap.java文件

该文件具有应用程序级逻辑,可以使用ResultMap从Employee表读取记录-

import com.ibatis.common.resources.Resources;
import com.ibatis.sqlmap.client.SqlMapClient;
import com.ibatis.sqlmap.client.SqlMapClientBuilder;

import java.io.*;
import java.sql.SQLException;
import java.util.*;

public class IbatisResultMap{
   public static void main(String[] args)
   throws IOException,SQLException{
      Reader rd = Resources.getResourceAsReader("SqlMapConfig.xml");
      SqlMapClient smc = SqlMapClientBuilder.buildSqlMapClient(rd);

      int id = 1;
      System.out.println("Going to read record.....");
      Employee e = (Employee)smc.queryForObject ("Employee.useResultMap", id);

      System.out.println("ID:  " + e.getId());
      System.out.println("First Name:  " + e.getFirstName());
      System.out.println("Last Name:  " + e.getLastName());
      System.out.println("Salary:  " + e.getSalary());
      System.out.println("Record read Successfully ");
   }
} 

编译并运行

这是编译和运行上述软件的步骤。在继续进行编译和执行之前,请确保已正确设置了PATH和CLASSPATH。

  • 如上所示创建Employee.xml。
  • 如上所示创建Employee.java并进行编译。
  • 如上所示创建IbatisResultMap.java并进行编译。
  • 执行IbatisResultMap二进制文件以运行程序。

您将获得以下结果,这是对EMPLOYEE表的读取操作。

Going to read record.....
ID:  1
First Name:  Zara
Last Name:  Ali
Salary:  5000
Record read Successfully