目录

Spring JDBC Example

要了解与JdbcTemplate类相关的Spring JDBC框架的概念,让我们编写一个简单的示例,它将在以下Student表上实现所有CRUD操作。

CREATE TABLE Student(
   ID   INT NOT NULL AUTO_INCREMENT,
   NAME VARCHAR(20) NOT NULL,
   AGE  INT NOT NULL,
   PRIMARY KEY (ID)
);

在继续之前,让我们有一个可用的Eclipse IDE,并按照以下步骤创建一个Spring应用程序 -

脚步 描述
1 创建一个名为SpringExample的项目,并在创建的项目中的src文件夹下创建一个包com.iowiki
2 使用Add External JARs选项添加所需的Spring库,如Spring Hello World Example章节中所述。
3 在项目中添加Spring JDBC特定的最新库mysql-connector-java.jarorg.springframework.jdbc.jarorg.springframework.transaction.jar 。 如果您还没有库,可以下载所需的库。
4 创建DAO接口StudentDAO并列出所有必需的方法。 虽然它不是必需的,你可以直接写StudentJDBCTemplate课程,但作为一个好习惯,让我们这样做。
5com.iowiki包下创建其他所需的Java类StudentStudentJDBCTemplateStudentJDBCTemplateMainApp
6 确保您已在TEST数据库中创建了Student表。 还要确保您的MySQL服务器工作正常,并且您使用给定用户名和密码对数据库具有读/写访问权限。
7src文件夹下创建Beans配置文件Beans.xml
8 最后一步是创建所有Java文件和Bean配置文件的内容并运行应用程序,如下所述。

以下是数据访问对象接口文件StudentDAO.java -

package com.iowiki;
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
      * a record from the Student table corresponding
      * to a passed student id.
   */
   public Student getStudent(Integer id);
   /** 
      * This is the method to be used to list down
      * all the records from the Student table.
   */
   public List<Student> listStudents();
   /** 
      * This is the method to be used to delete
      * a record from the Student table corresponding
      * to a passed student id.
   */
   public void delete(Integer id);
   /** 
      * This is the method to be used to update
      * a record into the Student table.
   */
   public void update(Integer id, Integer age);
}

以下是Student.java文件的内容

package com.iowiki;
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.iowiki;
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StudentJDBCTemplate.java的实现类文件StudentJDBCTemplate.java

package com.iowiki;
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 SQL = "insert into Student (name, age) values (?, ?)";
      jdbcTemplateObject.update( SQL, name, age);
      System.out.println("Created Record Name = " + name + " Age = " + age);
      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;
   }
   public List<Student> listStudents() {
      String SQL = "select * from Student";
      List <Student> students = jdbcTemplateObject.query(SQL, new StudentMapper());
      return students;
   }
   public void delete(Integer id) {
      String SQL = "delete from Student where id = ?";
      jdbcTemplateObject.update(SQL, id);
      System.out.println("Deleted Record with ID = " + id );
      return;
   }
   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;
   }
}

以下是MainApp.java文件的内容

package com.iowiki;
import java.util.List;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import com.iowiki.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<Student> 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());
      }
      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 = "password"/>
   </bean>
   <!-- Definition for studentJDBCTemplate bean -->
   <bean id = "studentJDBCTemplate" 
      class = "com.iowiki.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 -

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

您可以自己尝试删除操作,我们在示例中没有使用它,但现在您有一个基于Spring JDBC框架的工作应用程序,您可以根据项目要求扩展它以添加复杂的功能。 还有其他方法可以访问数据库,您将使用NamedParameterJdbcTemplateSimpleJdbcTemplate类,因此如果您有兴趣学习这些类,请查看Spring Framework的参考手册。

↑回到顶部↑
WIKI教程 @2018