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
   
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