【Spring Framework】Spring 事务使用的完整示例

为了详细展示 Spring 事务的使用，我将提供一个完整的示例，包括配置、代码和说明。这将涵盖以下几个方面：

数据库配置：包括数据源和事务管理器的配置。
实体类：用于数据库操作的数据模型。
DAO 层：数据访问对象，用于执行数据库操作。
服务层：业务逻辑层，包含事务管理的业务方法。
配置：包括 Java 配置和 XML 配置示例。
测试：如何测试事务管理的功能。

示例项目结构

假设我们有一个简单的 Spring 项目，用于处理用户的 CRUD 操作，以下是示例项目的主要结构：

src/main/java└── com└── example├── config│   ├── AppConfig.java│   └── TransactionConfig.xml├── dao│   └── UserDao.java├── entity│   └── User.java├── service│   └── UserService.java└── test└── UserServiceTest.java

一、数据库配置

1. 数据源配置

Java 配置 (AppConfig.java)

package com.example.config;import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.datasource.DriverManagerDataSource;
import org.springframework.transaction.PlatformTransactionManager;
import org.springframework.transaction.annotation.EnableTransactionManagement;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;import javax.sql.DataSource;@Configuration
@EnableTransactionManagement
@ComponentScan(basePackages = "com.example") // 扫描指定包下的组件
public class AppConfig {@Beanpublic DataSource dataSource() {DriverManagerDataSource dataSource = new DriverManagerDataSource();dataSource.setDriverClassName("com.mysql.cj.jdbc.Driver");dataSource.setUrl("jdbc:mysql://localhost:3306/testdb");dataSource.setUsername("root");dataSource.setPassword("password");return dataSource;}@Beanpublic JdbcTemplate jdbcTemplate(DataSource dataSource) {return new JdbcTemplate(dataSource);}@Beanpublic PlatformTransactionManager transactionManager(DataSource dataSource) {return new DataSourceTransactionManager(dataSource);}
}

XML 配置 (TransactionConfig.xml)

<beans xmlns="http://www.springframework.org/schema/beans"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xmlns:tx="http://www.springframework.org/schema/tx"xsi:schemaLocation="http://www.springframework.org/schema/beanshttp://www.springframework.org/schema/beans/spring-beans.xsdhttp://www.springframework.org/schema/txhttp://www.springframework.org/schema/tx/spring-tx.xsd"><!-- 数据源配置 --><bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource"><property name="driverClassName" value="com.mysql.cj.jdbc.Driver"/><property name="url" value="jdbc:mysql://localhost:3306/testdb"/><property name="username" value="root"/><property name="password" value="password"/></bean><!-- JdbcTemplate 配置 --><bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate"><property name="dataSource" ref="dataSource"/></bean><!-- 事务管理器配置 --><bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager"><property name="dataSource" ref="dataSource"/></bean><!-- 启用事务管理 --><tx:annotation-driven transaction-manager="transactionManager"/><!-- 扫描包路径 --><context:component-scan base-package="com.example"/>
</beans>

二、实体类

User.java

package com.example.entity;public class User {private int id;private String username;private String password;// Getters and Setterspublic int getId() {return id;}public void setId(int id) {this.id = id;}public String getUsername() {return username;}public void setUsername(String username) {this.username = username;}public String getPassword() {return password;}public void setPassword(String password) {this.password = password;}
}

三、DAO 层

UserDao.java

package com.example.dao;import com.example.entity.User;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Repository;@Repository
public class UserDao {@Autowiredprivate JdbcTemplate jdbcTemplate;public void createUser(User user) {String sql = "INSERT INTO users (username, password) VALUES (?, ?)";jdbcTemplate.update(sql, user.getUsername(), user.getPassword());}public User getUserById(int id) {String sql = "SELECT * FROM users WHERE id = ?";return jdbcTemplate.queryForObject(sql, new Object[]{id}, (rs, rowNum) -> {User user = new User();user.setId(rs.getInt("id"));user.setUsername(rs.getString("username"));user.setPassword(rs.getString("password"));return user;});}public void updateUser(User user) {String sql = "UPDATE users SET username = ?, password = ? WHERE id = ?";jdbcTemplate.update(sql, user.getUsername(), user.getPassword(), user.getId());}public void deleteUser(int id) {String sql = "DELETE FROM users WHERE id = ?";jdbcTemplate.update(sql, id);}
}

四、服务层

UserService.java

package com.example.service;import com.example.dao.UserDao;
import com.example.entity.User;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;@Service
public class UserService {@Autowiredprivate UserDao userDao;@Transactionalpublic void createUser(User user) {userDao.createUser(user);// Simulate an exception to test rollbackif ("error".equals(user.getUsername())) {throw new RuntimeException("Simulated exception");}}@Transactionalpublic void updateUser(User user) {userDao.updateUser(user);// Simulate an exception to test rollbackif ("error".equals(user.getUsername())) {throw new RuntimeException("Simulated exception");}}
}

五、测试

UserServiceTest.java

package com.example.test;import com.example.config.AppConfig;
import com.example.entity.User;
import com.example.service.UserService;
import org.junit.jupiter.api.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.transaction.TransactionStatus;
import org.springframework.transaction.support.DefaultTransactionDefinition;
import org.springframework.transaction.PlatformTransactionManager;
import org.springframework.transaction.TransactionDefinition;import static org.junit.jupiter.api.Assertions.assertThrows;public class UserServiceTest {@Testpublic void testCreateUserWithTransaction() {ApplicationContext context = new AnnotationConfigApplicationContext(AppConfig.class);UserService userService = context.getBean(UserService.class);User user = new User();user.setUsername("normaluser");user.setPassword("password");// Test normal behavioruserService.createUser(user);// Test exception and rollbackUser errorUser = new User();errorUser.setUsername("error");errorUser.setPassword("password");assertThrows(RuntimeException.class, () -> {userService.createUser(errorUser);});}@Testpublic void testUpdateUserWithTransaction() {ApplicationContext context = new AnnotationConfigApplicationContext(AppConfig.class);UserService userService = context.getBean(UserService.class);User user = new User();user.setId(1); // assuming user with ID 1 existsuser.setUsername("updateduser");user.setPassword("newpassword");// Test normal behavioruserService.updateUser(user);// Test exception and rollbackUser errorUser = new User();errorUser.setId(1); // assuming user with ID 1 existserrorUser.setUsername("error");errorUser.setPassword("newpassword");assertThrows(RuntimeException.class, () -> {userService.updateUser(errorUser);});}
}