以下示例将演示如何使用Spring JDBC进行批量更新.我们将在单个批处理操作中更新Student表中的可用记录.
String SQL = "update Student set age = ? where id = ?"; int[] updateCounts = jdbcTemplateObject.batchUpdate(SQL, new BatchPreparedStatementSetter() { public void setValues(PreparedStatement ps, int i) throws SQLException { ps.setInt(1, students.get(i).getAge()); ps.setInt(2, students.get(i).getId()); } public int getBatchSize() { return students.size(); } });
其中,
SQL : 更新查询以更新学生的年龄.
jdbcTemplateObject : StudentJDBCTemplate对象用于更新数据库中的学生对象.
BatchPreparedStatementSetter : 批处理执行程序,在每个项目的PerparedStatement中设置值,由对象student和index i列表标识. getBatchSize()返回批量的大小.
updateCounts : 包含每个更新查询的更新行数的Int数组.
为了理解与Spring JDBC相关的上述概念,让我们编写一个示例这将更新批处理操作.要编写我们的示例,让我们使用一个可用的Eclipse IDE并使用以下步骤创建一个Spring应用程序.
Step | 描述 |
---|---|
1 | 更新在章节下创建的项目学生Spring JDBC - First Application . |
2 | 更新bean配置并运行应用程序,如下所述. |
以下是数据访问对象接口文件的内容 StudentDAO.java .
package com.it1352; 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 batchUpdate(final List<Student> students); }
以下是 Student.java 文件的内容.
package com.it1352; 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 StudentMapper.java 文件的内容.
package com.it1352; 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; } }
以下是定义的DAO接口StudentDAO的实现类文件 StudentJDBCTemplate.java .
package com.it1352; import java.sql.PreparedStatement; import java.util.List; import javax.sql.DataSource; import org.springframework.jdbc.core.JdbcTemplate; import org.springframework.jdbc.core.BatchPreparedStatementSetter; import java.sql.SQLException; 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 = ? where id = ?"; int[] updateCounts = jdbcTemplateObject.batchUpdate(SQL, new BatchPreparedStatementSetter() { public void setValues(PreparedStatement ps, int i) throws SQLException { ps.setInt(1, students.get(i).getAge()); ps.setInt(2, students.get(i).getId()); } public int getBatchSize() { return students.size(); } }); System.out.println("Records updated!"); } }
以下是 MainApp.java 文件的内容.
package com.it1352; import java.util.ArrayList; import java.util.List; import org.springframework.context.ApplicationContext; import org.springframework.context.support.ClassPathXmlApplicationContext; public class MainApp { public static void main(String[] args) { ApplicationContext context = new ClassPathXmlApplicationContext("Beans.xml"); StudentJDBCTemplate studentJDBCTemplate = (StudentJDBCTemplate)context.getBean("studentJDBCTemplate"); 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(10); Student student1 = new Student(); student1.setId(3); student1.setAge(10); 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()); } } }
以下是配置文件 Beans.xml .
<?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"/> <property name = "username" value = "root"/> <property name = "password" value = "admin"/> </bean> <!-- Definition for studentJDBCTemplate bean --> <bean id = "studentJDBCTemplate" class = "com.IT屋.StudentJDBCTemplate"> <property name = "dataSource" ref = "dataSource" /> </bean> </beans>
完成源和bean配置文件的创建后,让我们运行应用程序.如果你的申请一切正常,它将打印以下信息.
Initial Students ID : 1, Age : 11 ID : 3, Age : 15 Records updated! Updated Students ID : 1, Age : 10 ID : 3, Age : 10