Spring JDBC 更新查询

以下示例将演示如何使用Spring JDBC更新查询。我们将更新学生表中的可用记录。

句法

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

updateQuery - 更新查询以使用占位符更新学生。
jdbcTemplateObject - 用于更新数据库中student对象的StudentJDBCTemplate对象。

为了理解与Spring JDBC相关的上述概念，让我们编写一个更新查询的示例。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。

序号	描述
1	更新在Spring JDBC - 第一个应用章节下创建的项目Student。
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 StudentDAO.java 的内容。

package com.codingdict;

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);   
}

以下是 Student.java 文件的内容。

package com.codingdict;

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.codingdict;

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.codingdict;

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

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 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;
   }
   public Student getStudent(Integer id) {
      String SQL = "select * from Student where id = ?";
      Student student = jdbcTemplateObject.queryForObject(
         SQL, new Object[]{id}, new StudentMapper());

      return student;
   }
}

以下是 MainApp.java 文件的内容。

package com.codingdict;

import java.util.List;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import com.codingdict.StudentJDBCTemplate;

public class MainApp {
   public static void main(String[] args) {
      ApplicationContext context = new ClassPathXmlApplicationContext("Beans.xml");
      StudentJDBCTemplate studentJDBCTemplate =
         (StudentJDBCTemplate)context.getBean("studentJDBCTemplate");

      System.out.println("----Updating Record with ID = 2 -----" );
      studentJDBCTemplate.update(2, 20);

      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());  
   }
}

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.codingdict.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。如果您的应用程序一切正常，它将打印以下消息。

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