我们在上一章讨论了如何使用iBATIS对表执行READ操作.本章介绍如何使用iBATIS更新表中的记录.
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) );
此表只有一条记录如下 :
mysql> select * from EMPLOYEE; +----+------------+-----------+--------+ | id | first_name | last_name | salary | +----+------------+-----------+--------+ | 1 | Zara | Ali | 5000 | +----+------------+-----------+--------+ 1 row in set (0.00 sec)
要执行udpate操作,您需要修改Employee. java文件如下 :
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 */
要使用iBATIS定义SQL映射语句,我们将添加< update>在Employee.xml中标记,在这个标记定义中,我们将定义一个"id",它将在IbatisUpdate.java文件中用于在数据库上执行SQL UPDATE查询.
<?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>
此文件具有应用程序级逻辑,用于将记录更新为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 "); } }
以下是编译和运行的步骤上述软件.在继续进行编译和执行之前,请确保已正确设置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IbatisUpdate.java并进行编译.
执行IbatisUpdate二进制文件以运行程序.
您将获得以下结果,并且记录将在EMPLOYEE表中更新,之后,相同的记录将从EMPLOYEE表中读取.
Going to update record..... Record updated Successfully Going to read records..... 1 Roma Ali 5000 Records Read Successfully