Springjdbc 简明教程

Spring JDBC - Objects Batch Operation

以下示例将演示如何在 Spring JDBC 中使用对象进行批量更新。我们将在一个批量操作中更新 Student 表中可用的记录。

Syntax

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!");

其中，

SQL - 用于更新学生年龄的 update 查询。
jdbcTemplateObject - 用于更新数据库中 student 对象的 StudentJDBCTemplate 对象。
batch - 表示一批对象的 SqlParameterSource 对象。
updateCounts - 包含每次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，我们编写一个将更新一个批量操作的示例。为了编写我们的示例，让我们有一个可用的 Eclipse IDE 并使用以下步骤创建一个 Spring 应用程序。

Step

Description

更新在第 Spring JDBC - First Application 章创建的 Student 项目。

更新 bean 配置并按如下说明运行应用程序。

以下是对数据访问对象接口文件 StudentDAO.java 的内容。

package com.tutorialspoint;

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.tutorialspoint;

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;
   }
}

以下是对 StudentMapper.java 文件的内容。

package com.tutorialspoint;

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;
   }
}

以下是对所定义的 DAO 接口 StudentDAO 实现的类文件 StudentJDBCTemplate.java 。

package com.tutorialspoint;

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!");
   }
}

以下是 MainApp.java 文件的内容。

package com.tutorialspoint;

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(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.cj.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.tutorialspoint.StudentJDBCTemplate">
      <property name = "dataSource" ref = "dataSource" />
   </bean>
</beans>

一旦您完成创建源代码和 bean 配置文件，让我们运行此应用程序。如果应用程序一切正常，它将打印以下信息。

Initial Students
ID : 1, Age : 10
ID : 3, Age : 10
Records updated!
Updated Students
ID : 1, Age : 15
ID : 3, Age : 16