本章介紹了如何從使用iBATIS一個(gè)表中刪除記錄。

我們?cè)贛ySQL中下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)
);

假設(shè)該表有兩個(gè)記錄如下 -

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)

員工PO??JO類(lèi)

要執(zhí)行刪除操作，你并不需要修改Employee.java文件。讓我們保持它，因?yàn)樗窃谧詈笠徽隆?

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

要使用iBATIS定義SQL語(yǔ)句中的映射，我們會(huì)在Employee.xml添加<刪除>標(biāo)記和這個(gè)標(biāo)簽定義中，我們可以定義將在IbatisDelete.java文件可用于執(zhí)行SQL刪除數(shù)據(jù)庫(kù)查詢(xún)的“身份證”。

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE sqlMap PUBLIC "-//ibatis.apache.org//DTD SQL Map 2.0//EN" "http://ibatis.apache.org/dtd/sql-map-2.dtd">

<sqlMap namespace="Employee">

   <insert id="insert" parameterClass="Employee">
      INSERT INTO EMPLOYEE(first_name, last_name, salary)
      values (#first_name#, #last_name#, #salary#)

      <selectKey resultClass="int" keyProperty="id">
         select last_insert_id() as id
      </selectKey>
   </insert>

   <select id="getAll" resultClass="Employee">
      SELECT * FROM EMPLOYEE
   </select>

   <update id="update" parameterClass="Employee">
      UPDATE EMPLOYEE
      SET    first_name = #first_name#
      WHERE  id = #id#
   </update>

   <delete id="delete" parameterClass="int">
      DELETE FROM EMPLOYEE
      WHERE  id = #id#
   </delete>

</sqlMap>

IbatisDelete.java文件

此文件具有應(yīng)用程序級(jí)別邏輯刪除Employee表中的記錄 -

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

      /* This would delete one record in Employee table. */
      System.out.println("Going to delete record.....");
      int id = 1;

      smc.delete("Employee.delete", id );
      System.out.println("Record deleted Successfully ");

      System.out.println("Going to read records.....");
      List <Employee> ems = (List<Employee>)
         smc.queryForList("Employee.getAll", null);
      Employee em = null;
		
      for (Employee e : ems) {
         System.out.print("  " + e.getId());
         System.out.print("  " + e.getFirstName());
         System.out.print("  " + e.getLastName());
         System.out.print("  " + e.getSalary());
         em = e; 
         System.out.println("");
      }    

      System.out.println("Records Read Successfully ");
   }
} 

編譯和運(yùn)行

以下是編譯并運(yùn)行上述軟件的步驟。請(qǐng)確保您已設(shè)置PATH和CLASSPATH在進(jìn)行適當(dāng)?shù)木幾g和執(zhí)行之前。

• 創(chuàng)建Employee.xml如上所示。
• 創(chuàng)建Employee.java如上圖所示，并對(duì)其進(jìn)行編譯。
• 創(chuàng)建IbatisDelete.java如上圖所示，并對(duì)其進(jìn)行編譯。
• 執(zhí)行IbatisDelete二進(jìn)制運(yùn)行程序。

你會(huì)得到以下結(jié)果，并與ID = 1的記錄會(huì)從EMPLOYEE表中刪除并記錄的其余部分將被讀。

Going to delete record.....
Record deleted Successfully
Going to read records.....
   2  Roma  Ali  3000
Records Read Successfully