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:
步骤 | 描述 |
---|---|
1 | 创建一个名为 SpringExample 的项目,并在创建的项目中的 src 文件夹下创建包 com.tutorialspoint。 |
2 | 使用 Add External JARs 选项添加必需的 Spring 库,解释见 Spring Hello World Example 章节。 |
3 | 在项目中添加 Spring JDBC 指定的最新的库 mysql-connector-java.jar,org.springframework.jdbc.jar 和 org.springframework.transaction.jar。如果这些库不存在,你可以下载它们。 |
4 | 创建 DAO 接口 StudentDAO 并列出所有必需的方法。尽管这一步不是必需的而且你可以直接编写 StudentJDBCTemplate 类,但是作为一个好的实践,我们最好还是做这一步。 |
5 | 在 com.tutorialspoint 包下创建其他的必需的 Java 类 Student,StudentMapper,StudentJDBCTemplate 和 MainApp 。 |
6 | 确保你已经在 TEST 数据库中创建了 Student 表。并确保你的 MySQL 服务器运行正常,且你可以使用给出的用户名和密码读/写访问数据库。 |
7 | 在 src 文件夹下创建 Beans 配置文件 Beans.xml。 |
8 | 最后一步是创建所有的 Java 文件和 Bean 配置文件的内容并按照如下所示的方法运行应用程序。 |
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 = 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。