Spring JDBC 例子

http://www.yiibai.com/spring/spring_jdbc_example.html

要了解有关Spring JDBC框架与JdbcTemplate类的概念，让我们写这将实现所有在下面Student表的CRUD操作的简单例子。

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

在开始之前，让我们使用Eclipse IDE，并按照下面的步骤来创建一个Spring应用程序：

步骤	描述
1	Create a project with a name SpringExample and create a package com.yiibai under the src folder in the created project.
2	Add required Spring libraries using Add External JARs option as explained in the Spring Hello World Example chapter.
3	Add Spring JDBC specific latest libraries mysql-connector-java.jar,org.springframework.jdbc.jar and org.springframework.transaction.jar in the project. You can download required libraries if you do not have them already.
4	Create DAO interface StudentDAO and list down all the required methods. Though it is not required and you can directly write StudentJDBCTemplate class, but as a good practice, let's do it.
5	Create other required Java classes Student, StudentMapper, StudentJDBCTemplate andMainApp under the com.yiibai package.
6	Make sure you already created Student table in TEST database. Also make sure your MySQL server is working fine and you have read/write access on the database using the give username and password.
7	Create Beans configuration file Beans.xml under the src folder.
8	The final step is to create the content of all the Java files and Bean Configuration file 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.yiibai;

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.yiibai;

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.yiibai;

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;
   }
}

下面是实现类文件StudentJDBCTemplate.java 定义DAO接口StudentDAO：

package com.yiibai;

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.yiibai;

import java.util.List;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import com.yiibai.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文件：

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

</beans>

创建源代码和bean配置文件完成后，让我们运行应用程序。如果一切顺利，这将打印以下信息：

------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

你可以尝试删除操作，我在例子中没有使用过，但现在你有一个工作的应用程序基于Spring的JDBC框架，它可以扩展到根据项目要求增加复杂的功能。还有其他的方法来访问，将使用针对NamedParameterJdbcTemplate和SimpleJdbcTemplate类的数据库，所以如果你有兴趣学习这些课程，请参考Spring框架手册。