Ibatis 简明教程
iBATIS - Update Operation
在上一章中,我们讨论了如何使用 iBATIS 对表执行 READ 操作。本章将解释如何使用 iBATIS 更新表中的记录。
我们在 MySQL 中有以下“员工”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)
);
此表仅有一个记录,如下所示 -
mysql> select * from EMPLOYEE;
+----+------------+-----------+--------+
| id | first_name | last_name | salary |
+----+------------+-----------+--------+
| 1 | Zara | Ali | 5000 |
+----+------------+-----------+--------+
1 row in set (0.00 sec)
Employee POJO Class
要执行 udpate 操作,您需要如下修改 Employee.java 文件 -
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 File
要使用 iBATIS 定义 SQL 映射语句,我们将在 Employee.xml 中添加 <update> 标签,并且在此标签定义内,我们将定义一个“id”,该 id 将在 IbatisUpdate.java 文件中用于对数据库执行 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>
IbatisUpdate.java File
这个文件具有将记录更新到 Employee 表中的应用程序级逻辑 -
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 ");
}
}
Compilation and Run
以下是如何编译和运行上述软件的步骤。在继续编译和执行之前,请确保已正确设置 PATH 和 CLASSPATH。
-
按上述方式创建 Employee.xml。
-
按上述方式创建 Employee.java 并对其进行编译。
-
如上所示创建 IbatisUpdate.java 并编译它。
-
执行 IbatisUpdate 二进制文件来运行程序。
您会得到以下结果,并且会更新 EMPLOYEE 表中的一条记录,然后从 EMPLOYEE 表中读取同一条记录。
Going to update record.....
Record updated Successfully
Going to read records.....
1 Roma Ali 5000
Records Read Successfully