Spring JDBC 示例

Spring JDBC 示例

想要理解带有 jdbc 模板类的 Spring JDBC 框架的相关概念，让我们编写一个简单的示例，来实现下述 Student 表的所有 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，让我们适当地使用 Eclipse IDE 并按照如下所示的步骤创建一个 Spring 应用程序：

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    * 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);}

下面是 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<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;   }}

下面是为定义的 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 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.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<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());         }}

下述是配置文件 Beans.xml 的内容：

<?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.tutorialspoint.StudentJDBCTemplate">      <property name="dataSource"  ref="dataSource" />       </bean></beans>

当你完成创建源和 bean 配置文件后，运行应用程序。如果你的应用程序一切运行顺利的话，将会输出如下所示的消息：

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

你可以尝试自己删除在我的例子中我没有用到的操作，但是现在你有一个基于 Spring JDBC 框架的工作应用程序，你可以根据你的项目需求来扩展这个框架，添加复杂的功能。还有其他方法来访问你使用 NamedParameterJdbcTemplate 和 SimpleJdbcTemplate 类的数据库，所以如果你有兴趣学习这些类的话，那么你可以查看 Spring 框架的参考手册。