万字长文，带你从源码认识Spring事务原理，让Spring事务不再是面试噩梦

4.创建数据操作接口

public interface UserDao {

    /**
     * 插入
     * @param user    用户信息
     */
    void insertUser(JdbcUser user);

    /**
     * 根据 id 进行删除
     * @param id    主键
     */
    void deleteById(Integer id);

    /**
     * 查询
     * @return    全部
     */
    List<jdbcuser> selectAll();
}</jdbcuser>

5.创建数据操作接口实现类

跟书中例子不一样，没有在接口上加入事务注解，而是在公共方法上进行添加，可以在每个方法上自定义传播事件、隔离级别。

public class UserJdbcTemplate implements UserDao {

    private DataSource dataSource;

    private JdbcTemplate jdbcTemplate;


    @Override
    @Transactional(propagation = Propagation.REQUIRED)
    public void insertUser(JdbcUser user) {
        String sql = "insert into user (id, name, age) values (?, ?, ?)";
        jdbcTemplate.update(sql, user.getId(), user.getName(), user.getAge());
        System.out.println("Create record : " + user.toString());
    }

    @Override
    @Transactional
    public void deleteById(Integer id) {
        String sql = "delete from user where id = ?";
        jdbcTemplate.update(sql, id);
        System.out.println("Delete record, id = " + id);
        // 事务测试，抛出异常，让上面的插入操作回滚
        throw new RuntimeException("aa");
    }


    @Override
    public List<jdbcuser> selectAll() {
        String sql = "select * from user";
        List<jdbcuser> users = jdbcTemplate.query(sql, new UserRowMapper());
        return users;
    }



    public void setDataSource(DataSource dataSource) {
        // 使用 setter 注入参数时，同时初始化 jdbcTemplate
        this.dataSource = dataSource;
        this.jdbcTemplate = new JdbcTemplate(dataSource);
    }

}</jdbcuser></jdbcuser>

6.创建配置文件

<?xml version="1.0" encoding="UTF-8"?><beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:tx="http://www.springframework.org/schema/tx" xsi:schemalocation="http://www.springframework.org/schema/beans
       http://www.springframework.org/schema/beans/spring-beans.xsd
       http://www.springframework.org/schema/tx
       http://www.springframework.org/schema/tx/spring-tx.xsd"><!-- 数据源 MySQL --><bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource"><property name="driverClassName" value="com.mysql.jdbc.Driver"></property><property name="url" value="jdbc:mysql://localhost:3306/test?characterEncoding=utf8"></property><property name="username" value="root"></property><property name="password" value="12345678"></property></bean><bean id="userJdbcTemplate" class="transaction.UserJdbcTemplate"><property name="dataSource" ref="dataSource"></property></bean><!-- 开启事务，如果将这行去掉，将不会创建事务  --><a target='_blank'  href='https://www.17golang.com/gourl/?redirect=MDAwMDAwMDAwML57hpSHp6VpkrqbYLx2eayza4KafaOkbLS3zqSBrJvPsa5_0Ia6sWuR4Juaq6t9nq5roGCUgXuytMyerpZ5o9rFrWaamarQqJy5ZZrEZGCqtWyKmJOmnaTJp5enmHqJ3Metht6JtpyvmdSGnMOfnKmxpqSkfGx7rsiWt66CiYDcsYhz0YXNx2qFupdkr5yFZLKjkWF9s6WhvrezbH2rhM-trX_Pkre1bYWqgpyxhoKfsqN9Y4mmhrG0t81tg3mM37Jmft6FlblqkeCKmrGDbXE' rel='nofollow'>Spring编程式和声明式事务实例讲解</a>
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<strong>在目标方法执行前获取事务并收集事务信</strong>息：<pre class="brush:go;">createTransactionIfNecessary(tm, txAttr, joinpointIdentification)

invocation.proceed()

completeTransactionAfterThrowing(txInfo, ex);

cleanupTransactionInfo(txInfo)

commitTransactionAfterReturning(txInfo)

事务回滚 & 提交

这两步操作，主要调用了底层数据库连接的

API