iBATIS更新操作

上一章展示了如何使用iBATIS对表进行读取操作。本章将告诉你如何在一个表中使用iBATIS更新记录。

我们已经在MySQL下有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) );

此表有如下只有一条记录：

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

Employee POJO 类:

要执行UDPATE操作，需要修改Employee.java文件，如下所示：

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:

要定义使用iBATIS SQL映射语句，我们想补充的<Update>标签Employee.xml文件，这个标签定义中，我们会定义将用于在IbatisUpdate.java文件的数据库执行SQL UPDATE查询的“id”。

<?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> </sqlMap>

IbatisUpdate.java 文件:

文件将应用程序级别的逻辑来更新记录到Employee表：

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 IbatisUpdate{ public static void main(String[] args) throws IOException,SQLException{ Reader rd = Resources.getResourceAsReader("SqlMapConfig.xml"); SqlMapClient smc = SqlMapClientBuilder.buildSqlMapClient(rd); /* This would update one record in Employee table. */ System.out.println("Going to update record....."); Employee rec = new Employee(); rec.setId(1); rec.setFirstName( "Roma"); smc.update("Employee.update", rec ); System.out.println("Record updated 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 "); } } 

编译和运行：

下面是步骤来编译并运行上述软件。请确保您已在进行的编译和执行之前，适当地设置PATH和CLASSPATH。

• 创建Employee.xml如上所示。

• 创建Employee.java如上图所示，并编译它。

• 创建IbatisUpdate.java如上图所示，并编译它。

• 执行IbatisUpdate二进制文件来运行程序。

得到下面的结果，并创建纪录在EMPLOYEE表进行更新和更高版本相同的记录将从EMPLOYEE表中读出。

Going to update record..... Record updated Successfully Going to read records..... 1 Roma Ali 5000 Records Read Successfully