Spring学习四-Spring中的 JdbcTemplate 以及 Spring 事务控制

1、Spring 中的 JdbcTemplate

UserDao 中使用 JdbcTemplate

@Repository("userDao")
public class UserDao {

    @Autowired
    private JdbcTemplate jdbcTemplate;


    public int saveUser(User user) {
        return jdbcTemplate.update("insert into user(name,age) values(?,?)", user.getName(), user.getAge());
    }

    public List<User> list() {
        return jdbcTemplate.query("select * from user", new RowMapperImpl());
    }

    public int deleteUser(Integer userId) {
        return jdbcTemplate.update("delete from user where id=?", userId);
    }

    public User getUserById(Integer id) {
        List<User> query = jdbcTemplate.query("select * from user where id = ?", new RowMapperImpl(), id);
        if (query == null || query.isEmpty()) {
            return null;
        }
        if (query.size() > 1) {
            throw new RuntimeException("查询出来的数据不唯一");
        }
        return query.get(0);
    }

    public class RowMapperImpl implements RowMapper<User> {

        public User mapRow(ResultSet resultSet, int i) throws SQLException {
            User user = new User();
            user.setAge(resultSet.getInt("age"));
            user.setId(resultSet.getInt("id"));
            user.setName(resultSet.getString("name"));
            user.setMoney(resultSet.getBigDecimal("money"));
            return user;
        }
    }

    public void updateUser(User user) {
        jdbcTemplate.update("update user set age=?,name=?,money=? where id=?", user.getAge(), user.getName(), user.getMoney(), user.getId());
    }
}

2、Spring 的事务控制

2.1、PlatformTransactionManager

此接口是 spring 的事务管理器，它里面提供了我们常用的操作事务的方法，

public interface PlatformTransactionManager extends TransactionManager {
  	// 获取事务状态信息
    TransactionStatus getTransaction(@Nullable TransactionDefinition var1) throws TransactionException;
		// 提交事务
    void commit(TransactionStatus var1) throws TransactionException;
		// 回滚事务
    void rollback(TransactionStatus var1) throws TransactionException;
}

2.2、TransactionDefinition

public interface TransactionDefinition {
    int PROPAGATION_REQUIRED = 0;
    int PROPAGATION_SUPPORTS = 1;
    int PROPAGATION_MANDATORY = 2;
    int PROPAGATION_REQUIRES_NEW = 3;
    int PROPAGATION_NOT_SUPPORTED = 4;
    int PROPAGATION_NEVER = 5;
    int PROPAGATION_NESTED = 6;
    int ISOLATION_DEFAULT = -1;
    int ISOLATION_READ_UNCOMMITTED = 1;
    int ISOLATION_READ_COMMITTED = 2;
    int ISOLATION_REPEATABLE_READ = 4;
    int ISOLATION_SERIALIZABLE = 8;
    int TIMEOUT_DEFAULT = -1;

    default int getPropagationBehavior() {
        return 0;
    }

    default int getIsolationLevel() {
        return -1;
    }

    default int getTimeout() {
        return -1;
    }

    default boolean isReadOnly() {
        return false;
    }

    @Nullable
    default String getName() {
        return null;
    }

    static TransactionDefinition withDefaults() {
        return StaticTransactionDefinition.INSTANCE;
    }
}

2.2.1、事务中提供的方法

• String getName()获取事务对象的名称
• int getIsolationLevel() 获取事务的隔离级别
• int getPropagationBehavior() 获取事务的传播行为
• int getTimeout() 获取事务的超时时间
• boolean isReadOnly() 获取事务是否是只读

2.2.2、事务的隔离级别

• ISOLATION_DEFAULT 默认级别
• ISOLATION_READ_UNCOMMITTED 可以读取未提交数据
• ISOLATION_READ_COMMITTED 只能读取已提交数据，解决脏读问题（oracle默认级别）
• ISOLATION_REPEATABLE_READ 是否读取其他事务提交修改后的数据，解决不可重复读问题（MySQL默认级别）
• ISOLATION_SERIALIZABLE 是否读取其他事务提交添加后的数据，解决幻影读问题

2.2.3、事务的传播行为

• REQUIRED:如果当前没有事务，就新建一个事务，如果已经存在一个事务 中，加入到这个事务 中。一般的选 择(默认值)
• SUPPORTS:支持当前事务，如果当前没有事务，就以非事务方式执行(没有事务)
• MANDATORY:使用当前的事务，如果当前没有事务，就抛出异常
• REQUERS_NEW:新建事务，如果当前在事务中，把当前事务挂起
• NOT_SUPPORTED:以非事务方式执行操作，如果当前存在事务，就把当前事务挂起
• NEVER:以非事务方式运行，如果当前存在事务，抛出异常
• NESTED:如果当前存在事务，则在嵌套事务内执行。如果当前没有事务，则执行 REQUIRED 类似的操作。

2.3、使用Spring事务

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.wmding.spring</groupId>
    <artifactId>com.wmding.spring</artifactId>
    <version>1.0-SNAPSHOT</version>

    <dependencies>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>5.2.1.RELEASE</version>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>RELEASE</version>
        </dependency>

        <dependency>
            <groupId>commons-dbutils</groupId>
            <artifactId>commons-dbutils</artifactId>
            <version>1.4</version>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.46</version>
        </dependency>

        <dependency>
            <groupId>c3p0</groupId>
            <artifactId>c3p0</artifactId>
            <version>0.9.1.2</version>
        </dependency>

        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-test</artifactId>
            <version>5.2.2.RELEASE</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>5.2.2.RELEASE</version>
        </dependency>
    </dependencies>

</project>

@Configuration
@ComponentScan(value = "com.wmding.spring")
@Import(value = {JdbcConfig.class,TransactionConfig.class})
@EnableTransactionManagement
public class SpringConfig {
    
}

@PropertySource(value = "classpath:jdbc.properties")
public class JdbcConfig {

    @Value("${jdbc.driver}")
    private String driver;

    @Value("${jdbc.url}")
    private String url;


    @Value("${jdbc.username}")
    private String username;


    @Value("${jdbc.password}")
    private String password;


    @Bean("jdbcTemplate")
    public JdbcTemplate jdbcTemplate(DataSource dataSource){
        return new JdbcTemplate(dataSource);
    }

    @Bean("dataSource")
    public DataSource createDataSource(){
        DriverManagerDataSource dataSource = new DriverManagerDataSource();
        dataSource.setDriverClassName(driver);
        dataSource.setUrl(url);
        dataSource.setUsername(username);
        dataSource.setPassword(password);
        return dataSource;
    }
}

public class TransactionConfig {

    @Bean("transactionManager")
    public PlatformTransactionManager dataSourceTransationManager(DataSource dateSource){
        return new DataSourceTransactionManager(dateSource);
    }
}

@Repository("userDao")
public class UserDao {

    @Autowired
    private JdbcTemplate jdbcTemplate;


    public int saveUser(User user) {
        return jdbcTemplate.update("insert into user(name,age) values(?,?)", user.getName(), user.getAge());
    }

    public List<User> list() {
        return jdbcTemplate.query("select * from user", new RowMapperImpl());
    }

    public int deleteUser(Integer userId) {
        return jdbcTemplate.update("delete from user where id=?", userId);
    }

    public User getUserById(Integer id) {
        List<User> query = jdbcTemplate.query("select * from user where id = ?", new RowMapperImpl(), id);
        if (query == null || query.isEmpty()) {
            return null;
        }
        if (query.size() > 1) {
            throw new RuntimeException("查询出来的数据不唯一");
        }
        return query.get(0);
    }

    public class RowMapperImpl implements RowMapper<User> {

        public User mapRow(ResultSet resultSet, int i) throws SQLException {
            User user = new User();
            user.setAge(resultSet.getInt("age"));
            user.setId(resultSet.getInt("id"));
            user.setName(resultSet.getString("name"));
            user.setMoney(resultSet.getBigDecimal("money"));
            return user;
        }
    }

    public void updateUser(User user) {
        jdbcTemplate.update("update user set age=?,name=?,money=? where id=?", user.getAge(), user.getName(), user.getMoney(), user.getId());
    }
}

@Service("userService")
@Transactional(readOnly = true,propagation = Propagation.SUPPORTS)
public class UserServiceImpl implements UserService {

    @Autowired
    private UserDao userDao;

    public int saveUser(User user) {
        return userDao.saveUser(user);
    }

    public List<User> list() {
        return userDao.list();
    }

    public int deleteUser(Integer userId) {
        return userDao.deleteUser(userId);
    }

    public User getUserById(Integer id) {
        return userDao.getUserById(id);
    }

    public void updateUser(User user) {
        userDao.updateUser(user);
    }

    @Transactional(readOnly = false,propagation = Propagation.REQUIRED)
    public void transfer(Integer sourceId, Integer targetId, BigDecimal bigDecimal) {
        User sourceUser = userDao.getUserById(sourceId);
        User targetUser = userDao.getUserById(targetId);

        sourceUser.setMoney(sourceUser.getMoney().subtract(bigDecimal));
        userDao.updateUser(sourceUser);


        targetUser.setMoney(targetUser.getMoney().add(bigDecimal));
        userDao.updateUser(targetUser);
    }
}

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(classes = SpringConfig.class)
public class UserTest {

    @Autowired
    private UserService userService;

    @Test
    public void saveUser() {
        User user = new User();
        user.setAge(20);
        user.setName("wmding");
        user.setMoney(new BigDecimal(10000));
        int i = userService.saveUser(user);
        if (i > 0) {
            System.out.println("saveUser success");
        }
    }

    @Test
    public void getUserById() {
        User userById = userService.getUserById(1);
        System.out.println(userById.toString());
    }

    @Test
    public void transfer() {
        userService.transfer(1, 2, new BigDecimal(100));
    }
}