Spring JDBC 示例
为了理解 Spring JDBC 框架与 JdbcTemplate 类相关的概念，让我们编写一个简单的示例，它将实现以下 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) );
Before proceeding, 让我们有一个可以工作的 Eclipse IDE，并按照以下步骤创建一个 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 文件夹下创建一个包 com.tutorialspoint。 |
| 2 | 使用 Add External JARs 选项添加所需的 Spring 库，如 Spring Hello World 示例 一章中所述。 |
| 3 | 在项目中添加Spring JDBC特定的最新库mysql-connector-java.jar、org.springframework.jdbc.jar和org.springframework.transaction.jar。 如果您还没有所需的库，您可以下载它们。 |
| 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，您可以直接编写 StudentJDBCTemplate 类，但作为一种好的做法，让我们这样做。 |
| 5 | 在 com.tutorialspoint 包下创建其他所需的 Java 类 Student、StudentMapper、StudentJDBCTemplate 和 MainApp。 |
| 6 | 确保您已经在 TEST 数据库中创建了 Student 表。 还要确保您的 MySQL 服务器工作正常，并且您可以使用给定的用户名和密码对数据库进行读/写访问。 |
| 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 Java 文件和 Bean 配置文件的内容，然后运行应用程序，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);
}
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<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 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());
}
}
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.tutorialspoint.StudentJDBCTemplate">
<property name = "dataSource" ref = "dataSource" />
</bean>
</beans>
完成创建源和 bean 配置文件后，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
您可以尝试自己删除该操作，我们在示例中没有使用该操作，但现在您有一个基于 Spring JDBC 框架的工作应用程序，您可以根据项目需求对其进行扩展以添加复杂的功能。 还有其他访问数据库的方法，您将在其中使用 NamedParameterJdbcTemplate 和 SimpleJdbcTemplate 类，所以如果您有兴趣学习这些类，请查看 Spring 框架的参考手册。
