以下示例将演示如何使用spring jdbc中的对象进行批量更新。我们将在单次批次操作中更新student表中的记录。
student表的结果如下 -
CREATE TABLE student(
id INT NOT NULL AUTO_INCREMENT,
name VARCHAR(20) NOT NULL,
age INT NOT NULL,
PRIMARY KEY (id)
);
语法：
String SQL = "update Student set age = :age where id = :id";
SqlParameterSource[] batch = SqlParameterSourceUtils.createBatch(students.toArray());
NamedParameterJdbcTemplate jdbcTemplateObject = new NamedParameterJdbcTemplate(dataSource);
int[] updateCounts = jdbcTemplateObject.batchUpdate(SQL,batch);
System.out.println("records updated!");
在上面语法中 -
SQL- 更新语句以更新学生的年龄。batch-SqlParameterSource对象表示一批对象。jdbcTemplateObject-NamedParameterJdbcTemplate对象来更新数据库中的学生对象。updateCounts-int数组包含每个更新查询更新的行计数(数量)。
创建项目
要了解上面提到的Spring JDBC相关的概念，这里创建一个项目用来演示如何执行对象批量更新。打开Eclipse IDE，并按照以下步骤创建一个名称为：ObjectsBatchOperation 的Spring应用程序项目。
步骤说明
- 参考第一个Spring JDBC项目来创建一个Maven项目 - http://www.yiibai.com/springjdbc/first_application.html
- 更新bean配置并运行应用程序。
完整的项目结构如下所示 -
文件 : pom.xml 的内容 -
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.yiibai</groupId>
<artifactId>ObjectsBatchOperation</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>ObjectsBatchOperation</name>
<url>http://maven.apache.org</url>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>3.8.1</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.40</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-jdbc</artifactId>
<version>4.1.0.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>4.1.4.RELEASE</version>
</dependency>
</dependencies>
</project>
以下是数据访问对象接口文件：StudentDAO.java的代码内容：
package com.yiibai;
import java.util.List;
import javax.sql.DataSource;
public interface StudentDAO {
/**
* This is the method to be used to initialize database resources ie.
* connection.
*/
public void setDataSource(DataSource ds);
/**
* This is the method to be used to list down all the records from the
* Student table.
*/
public List<Student> listStudents();
public void create(String name, Integer age);
public void batchUpdate(final List<Student> students);
}
以下是文件：Student.java的代码内容：
package com.yiibai;
public class Student {
private Integer age;
private String name;
private Integer id;
public void setAge(Integer age) {
this.age = age;
}
public Integer getAge() {
return age;
}
public void setName(String name) {
this.name = name;
}
public String getName() {
return name;
}
public void setId(Integer id) {
this.id = id;
}
public Integer getId() {
return id;
}
}
以下是文件：StudentMapper.java的代码内容：
package com.yiibai;
import java.sql.ResultSet;
import java.sql.SQLException;
import org.springframework.jdbc.core.RowMapper;
public class StudentMapper implements RowMapper<Student> {
public Student mapRow(ResultSet rs, int rowNum) throws SQLException {
Student student = new Student();
student.setId(rs.getInt("id"));
student.setName(rs.getString("name"));
student.setAge(rs.getInt("age"));
return student;
}
}
以下是文件：StudentJDBCTemplate.java的代码内容：
package com.yiibai;
import java.util.List;
import javax.sql.DataSource;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.namedparam.SqlParameterSource;
import org.springframework.jdbc.core.namedparam.SqlParameterSourceUtils;
import org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate;
public class StudentJDBCTemplate implements StudentDAO {
private DataSource dataSource;
private JdbcTemplate jdbcTemplateObject;
public void setDataSource(DataSource dataSource) {
this.dataSource = dataSource;
this.jdbcTemplateObject = new JdbcTemplate(dataSource);
}
public List<Student> listStudents() {
String SQL = "select * from Student";
List<Student> students = jdbcTemplateObject.query(SQL, new StudentMapper());
return students;
}
public void batchUpdate(final List<Student> students) {
String SQL = "update Student set age = :age where id = :id";
SqlParameterSource[] batch = SqlParameterSourceUtils.createBatch(students.toArray());
NamedParameterJdbcTemplate jdbcTemplateObject = new NamedParameterJdbcTemplate(dataSource);
int[] updateCounts = jdbcTemplateObject.batchUpdate(SQL, batch);
System.out.println("Records updated!");
}
public void create(String name, Integer age) {
// TODO Auto-generated method stub
String insertQuery = "insert into student (name, age) values (?, ?)";
jdbcTemplateObject.update(insertQuery, name, age);
System.out.println("Created Record Name = " + name + " Age = " + age);
return;
}
}
以下是程序执行入口文件：MainApp.java的代码内容：
package com.yiibai;
import java.util.ArrayList;
import java.util.List;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import com.yiibai.StudentJDBCTemplate;
public class MainApp {
public static void main(String[] args) {
ApplicationContext context = new ClassPathXmlApplicationContext("application-beans.xml");
StudentJDBCTemplate studentJDBCTemplate = (StudentJDBCTemplate) context.getBean("studentJDBCTemplate");
System.out.println("------Records Creation--------");
studentJDBCTemplate.create("Maxsu", 21);
studentJDBCTemplate.create("Curry", 22);
studentJDBCTemplate.create("Weiwei", 25);
List<Student> initialStudents = studentJDBCTemplate.listStudents();
System.out.println("Initial Students");
for (Student student2 : initialStudents) {
System.out.print("ID : " + student2.getId());
System.out.println(", Age : " + student2.getAge());
}
Student student = new Student();
student.setId(1);
student.setAge(15);
Student student1 = new Student();
student1.setId(3);
student1.setAge(16);
List<Student> students = new ArrayList<Student>();
students.add(student);
students.add(student1);
studentJDBCTemplate.batchUpdate(students);
List<Student> updatedStudents = studentJDBCTemplate.listStudents();
System.out.println("Updated Students");
for (Student student3 : updatedStudents) {
System.out.print("ID : " + student3.getId());
System.out.println(", Age : " + student3.getAge());
}
}
}
以下是Bean和数据库配置文件：application-beans.xml的代码内容：
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd ">
<!-- Initialization for data source -->
<bean id="dataSource"
class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="com.mysql.jdbc.Driver" />
<property name="url" value="jdbc:mysql://localhost:3306/test?characterEncoding=utf8&useSSL=true" />
<property name="username" value="root" />
<property name="password" value="123456" />
</bean>
<!-- Definition for studentJDBCTemplate bean -->
<bean id="studentJDBCTemplate" class="com.yiibai.StudentJDBCTemplate">
<property name="dataSource" ref="dataSource" />
</bean>
</beans>
注意： application-beans.xml 文件的位置是：{workspace}/fistapp/src/main/java 目录，如果放置错了，程序可能会因为找不到此配置文件而出错。
完成创建源代码和bean和数据库连接信息的文件配置后，运行应用程序。这里先简单说明一下运行的步骤，在项目名称(BatchOperation)上点击右键，在弹出的菜单中选择：【Run As】-> 【Maven test】
在运行测试成功后，应该会输出类似以下内容(含有 BUILD SUCCESS 的信息) 。
接下来，点击类文件：MainApp.java 选择【Run As】->【Java Application】，如果应用程序一切正常，这将打印以下消息：
------Records Creation--------
Created Record Name = Maxsu Age = 21
Created Record Name = Curry Age = 22
Created Record Name = Weiwei Age = 25
Initial Students
ID : 1, Age : 21
ID : 2, Age : 22
ID : 3, Age : 25
Records updated!
Updated Students
ID : 1, Age : 15
ID : 2, Age : 22
ID : 3, Age : 16
数据库中的student表中的数据被修改为：
mysql> select * from student;
+----+--------+-----+
| id | name | age |
+----+--------+-----+
| 1 | Maxsu | 15 |
| 2 | Curry | 22 |
| 3 | Weiwei | 16 |
+----+--------+-----+
3 rows in set
mysql>
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