Spring JDBC-创建查询

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📜 Spring JDBC-创建查询

📅 最后修改于: 2020-11-11 06:02:53 🧑 作者: Mango

以下示例将演示如何在Spring JDBC的帮助下使用插入查询创建查询。我们将在学生表中插入一些记录。

句法

String insertQuery = "insert into Student (name, age) values (?, ?)";
jdbcTemplateObject.update( insertQuery, name, age);

哪里，

insertQuery-插入具有占位符的查询。
jdbcTemplateObject -StudentJDBCTemplate对象，用于在数据库中插入学生对象。

为了理解与Spring JDBC相关的上述概念，让我们编写一个示例，该示例将插入查询。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 create
     * a record in the Student table.
   */
   public void create(String name, Integer age);
   
   /** 
      * This is the method to be used to list down
      * all the records from the Student table.
   */
   public List listStudents();   
}

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.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 create(String name, Integer age) {
      String insertQuery = "insert into Student (name, age) values (?, ?)";
      jdbcTemplateObject.update( insertQuery, name, age);
      System.out.println("Created Record Name = " + name + " Age = " + age);
      return;
   }
   public List listStudents() {
      String SQL = "select * from Student";
      List  students = jdbcTemplateObject.query(SQL, new StudentMapper());
      return students;
   }
}

以下是MainApp.java文件的内容。

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) {
      ApplicationContext context = new ClassPathXmlApplicationContext("Beans.xml");

      StudentJDBCTemplate studentJDBCTemplate = 
         (StudentJDBCTemplate)context.getBean("studentJDBCTemplate");
      
      System.out.println("------Records Creation--------" );
      studentJDBCTemplate.create("Zara", 11);
      studentJDBCTemplate.create("Nuha", 2);
      studentJDBCTemplate.create("Ayan", 15);

      System.out.println("------Listing Multiple Records--------" );
      List students = studentJDBCTemplate.listStudents();
      
      for (Student record : students) {
         System.out.print("ID : " + record.getId() );
         System.out.print(", Name : " + record.getName() );
         System.out.println(", Age : " + record.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。

------Records Creation--------
Created Record Name = Zara Age = 11
Created Record Name = Nuha Age = 2
Created Record Name = Ayan Age = 15
------Listing Multiple Records--------
ID : 1, Name : Zara, Age : 11
ID : 2, Name : Nuha, Age : 2
ID : 3, Name : Ayan, Age : 15