Spring JDBC - 更新查詢

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概述

以下示例將演示如何使用 Spring JDBC 更新查詢。我們將更新學生表中的可用記錄。

語法

String updateQuery = "update Student set age = ? where id = ?";
jdbcTemplateObject.update(updateQuery, age, id);

其中，

• updateQuery - 更新學生並帶有佔位符的更新查詢。

• jdbcTemplateObject - 用於在資料庫中更新學生物件的 StudentJDBCTemplate 物件。

示例

為了理解上面提到的與 Spring JDBC 相關的概念，讓我們編寫一個更新查詢的示例。為了編寫我們的示例，讓我們準備好一個可用的 Eclipse IDE，並使用以下步驟建立一個 Spring 應用程式。

StudentDAO.java

以下是資料訪問物件介面檔案StudentDAO.java的內容。

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 update
    * a record into the Student table.
   */
   public void update(Integer id, Integer age);

   /** 
    * This is the method to be used to list down
    * a record from the Student table corresponding
    * to a passed student id.
   */
   public Student getStudent(Integer id);   
}

Student.java

以下是Student.java檔案的內容。

package com.tutorialspoint;

// Student POJO for Student Table
public class Student {
   private Integer age;
   private String name;
   private Integer id;

   // setter/getter methods
   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;
   }
}

StudentMapper.java

以下是StudentMapper.java檔案的內容。

package com.tutorialspoint;

import java.sql.ResultSet;
import java.sql.SQLException;
import org.springframework.jdbc.core.RowMapper;

// Row Mapper Object to map Student table entry with Student Object
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;
   }
}

StudentJDBCTemplate.java

以下是為定義的 DAO 介面 StudentDAO 實現的類檔案StudentJDBCTemplate.java。

package com.tutorialspoint;

import java.util.List;
import javax.sql.DataSource;
import org.springframework.jdbc.core.JdbcTemplate;

// DAO instance to persist Student values
public class StudentJDBCTemplate implements StudentDAO {
   private DataSource dataSource;
   private JdbcTemplate jdbcTemplateObject;
   
   // set the datasource and jdbctemplate
   public void setDataSource(DataSource dataSource) {
      this.dataSource = dataSource;
      this.jdbcTemplateObject = new JdbcTemplate(dataSource);
   }
   
   // update the student age based on id   
   public void update(Integer id, Integer age){
      String SQL = "update Student set age = ? where id = ?";
      jdbcTemplateObject.update(SQL, age, id);
      System.out.println("Updated Record with ID = " + id );
      return;
   }
   
   // get the student based on id
   public Student getStudent(Integer id) {
      String SQL = "select * from Student where id = ?";
      Student student = jdbcTemplateObject.queryForObject(
         SQL, new Object[]{id}, new StudentMapper()
      );
      return student;
   }
}

MainApp.java

以下是MainApp.java檔案的內容。

package com.tutorialspoint;

import java.util.List;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import com.tutorialspoint.StudentJDBCTemplate;

public class MainApp {
   public static void main(String[] args) {
      // Create the application context by reading Beans.xml 
      ApplicationContext context = new ClassPathXmlApplicationContext("Beans.xml");
	  
	  // Create the JDBCTemplate instance from spring context
      StudentJDBCTemplate studentJDBCTemplate = 
         (StudentJDBCTemplate)context.getBean("studentJDBCTemplate");
      
      // update the student based on id
      System.out.println("----Updating Record with ID = 2 -----" );
      studentJDBCTemplate.update(2, 20);
      
      // get the student based on id and print its details
      System.out.println("----Listing Record with ID = 2 -----" );
      Student student = studentJDBCTemplate.getStudent(2);
      System.out.print("ID : " + student.getId() );
      System.out.print(", Name : " + student.getName() );
      System.out.println(", Age : " + student.getAge());  
   }
}

Beans.xml

以下是配置檔案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://: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>

輸出

建立原始檔和 bean 配置檔案後，讓我們執行應用程式。如果應用程式一切正常，它將列印以下訊息。

----Updating Record with ID = 2 -----
Updated Record with ID = 2
----Listing Record with ID = 2 -----
ID : 2, Name : Nuha, Age : 20