Spring JDBC-批处理操作

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📜 Spring JDBC-批处理操作

📅 最后修改于: 2020-11-11 06:07:48 🧑 作者: Mango

以下示例将演示如何使用Spring JDBC进行批处理更新。我们将通过一个批处理操作来更新Student表中的可用记录。

句法

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();
   }
});

哪里，

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-批处理执行器，在由学生列表和索引i标识的每个项目的PerparedStatement中设置值。 getBatchSize()返回批处理的大小。
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，让我们写一个示例来更新批处理操作。为了编写示例，让我们准备好一个可以运行的Eclipse IDE，并使用以下步骤创建一个Spring应用程序。

Step	Description
1	Update the project Student created under chapter Spring JDBC – First Application.
2	Update the bean configuration and run the application as explained below.

以下是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 listStudents();  

   public void batchUpdate(final List 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 {
   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;
   }
}

以下是已定义的DAO接口StudentDAO的实现类文件StudentJDBCTemplate.java 。

package com.tutorialspoint;

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 listStudents() {
      String SQL = "select * from Student";
      List  students = jdbcTemplateObject.query(SQL, 
                                new StudentMapper());
      return students;
   }
   public void batchUpdate(final List 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.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 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 students = new ArrayList();
      students.add(student);
      students.add(student1);

      studentJDBCTemplate.batchUpdate(students);

      List 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 。

完成创建源和Bean配置文件后，让我们运行该应用程序。如果您的应用程序一切正常，它将打印以下消息。

Initial Students
ID : 1, Age : 11
ID : 3, Age : 15
Records updated!
Updated Students
ID : 1, Age : 10
ID : 3, Age : 10