Spring Framework Other

2023-04-06, by alamide

1.单元测试

引入依赖

<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-test</artifactId>
    <version>6.0.7</version>
</dependency>

使用

@Slf4j
//@SpringJUnitConfig(classes = {SpringConfig.class}) //注解管理bean
@SpringJUnitConfig(locations = {"classpath:beans.xml"})//配置文件
class CalculatorImpTest {
    @Autowired
    private User user;
    
    @Test
    public void testCalculator(){
        log.info(user.toString());
    }
}

2.数据库事务

数据库的事务在这里

2.1 JDBC Template

引入依赖

<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-jdbc</artifactId>
    <version>6.0.7</version>
</dependency>

<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>8.0.32</version>
</dependency>

<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>druid</artifactId>
    <version>1.2.16</version>
</dependency>

配置 JavaBean

<contex:property-placeholder location="classpath:jdbc.properties"/>
<bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">
    <property name="username" value="${jdbc.username}"/>
    <property name="password" value="${jdbc.password}"/>
    <property name="url" value="${jdbc.url}"/>
    <property name="driverClassName" value="${jdbc.driverClass}"/>
</bean>

<bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
    <property name="dataSource" ref="dataSource"/>
</bean>

测试 JDBCTemplate

String sql = "select * from t_dept where dept_id=?";
final Dept dept = jdbcTemplate.queryForObject(sql, new BeanPropertyRowMapper<>(Dept.class), 1);
log.info(dept.toString());

2.2 配置事务

有一段转账的业务代码

public interface AccountDao {
    void sub(String account, int money);

    void add(String account, int money);
}

@Repository
@Slf4j
public class AccountDaoImpl implements AccountDao {
    @Autowired
    private JdbcTemplate jdbcTemplate;

    @Override
    public void sub(String account, int money) {
        String sql = "update t_account set balance=balance-? where account=?";
        final int update = jdbcTemplate.update(sql, money, account);
        log.info("sub: {}, account={}, money={}, effected {} rows", sql, account, money, update);
    }

    @Override
    public void add(String account, int money) {
        String sql = "update t_account set balance=balance+? where account=?";
        final int update = jdbcTemplate.update(sql, money, account);
        log.info("add: {}, account={}, money={}, effected {} rows", sql, account, money, update);
    }
}

public interface AccountService {
    void transMoney(String accountA, String accountB, int money);
}

@Service
public class AccountServiceImpl implements AccountService {

    @Autowired
    private AccountDao accountDao;

    @Override
    public void transMoney(String accountA, String accountB, int money) {
        accountDao.sub(accountA, money);
        int i = 1 / 0;
        accountDao.add(accountB, money);
    }
}

@Controller
public class AccountController {
    @Autowired
    private AccountService accountService;

    public void transMoney(String accountA, String accountB, int money){
        accountService.transMoney(accountA, accountB, money);
    }
}

@SpringJUnitConfig(locations = {"classpath:beans.xml"})
class AccountControllerTest {
    @Autowired
    private AccountController accountController;

    @Test
    public void testTrans(){
        accountController.transMoney("8859-1", "8859-2", 100);
    }
}

上面的代码会发生问题，

accountDao.sub(accountA, money);
int i = 1 / 0;
accountDao.add(accountB, money);

会发生 accountA 用户账户扣掉金额，而 accountB 用户账户却不能增加，这违背事务的一致性

可以配置事务来解决

配置 JavaBean

<bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
    <property name="dataSource" ref="dataSource"/>
</bean>
<tx:annotation-driven transaction-manager="transactionManager"/>

给方法上加上 @Transactional 注解（ @Transactional 也可以加在类上，加在类上表示所有方法都加上事务控制）

@Override
@Transactional
public void transMoney(String accountA, String accountB, int money) {
    accountDao.sub(accountA, money);
    int i = 1 / 0;
    accountDao.add(accountB, money);
}

@Transactional 还有一些其它的属性可以配置

timeout 超时回滚，释放资源
rollbackFor
noRollbackFor
isolation 隔离级别，有 READ UNCOMMITTED 、READ COMMITTED 、 REPEATABLE READ 、 SERIALIZABLE
propagation 传播行为，执行过程中多个方法上加上事务，事务是如何传递的？REQUIRED 没有就新建，有就加入；REQUIRES_NEW 每次都会新建一个事务；

全注解配置事务

@Configuration
@ComponentScan(basePackages = {"com.alamide.spring6"})
@EnableTransactionManagement
public class SpringConfig {
    @Bean("dataSource")
    public DataSource getDataSource(){
        DruidDataSource dataSource = new DruidDataSource();
        dataSource.setPassword("root");
        dataSource.setUsername("root");
        dataSource.setUrl("jdbc:mysql://localhost:3306/db_jdbc");
        dataSource.setDriverClassName("com.mysql.cj.jdbc.Driver");
        return dataSource;
    }

    @Bean("jdbcTemplate")
    public JdbcTemplate getJdbcTemplate(DataSource dataSource){
        JdbcTemplate jdbcTemplate = new JdbcTemplate();
        jdbcTemplate.setDataSource(dataSource);
        return jdbcTemplate;
    }

    @Bean("dataSourceTransactionManager")
    public DataSourceTransactionManager getDataSourceTransactionManager(DataSource dataSource){
        DataSourceTransactionManager dataSourceTransactionManager = new DataSourceTransactionManager();
        dataSourceTransactionManager.setDataSource(dataSource);
        return dataSourceTransactionManager;
    }
}

@Slf4j
@SpringJUnitConfig(classes = {SpringConfig.class})
public class JDBCTemplateTest {
    @Autowired
    private JdbcTemplate jdbcTemplate;

    @Test
    public void test(){
        String sql = "select * from t_dept where dept_id=?";
        final Dept dept = jdbcTemplate.queryForObject(sql, new BeanPropertyRowMapper<>(Dept.class), 1);
        log.info(dept.toString());
    }
}

基于 XML 声明事务，利用 Spring AOP

<contex:property-placeholder location="classpath:jdbc.properties"/>
<bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">
    <property name="username" value="${jdbc.username}"/>
    <property name="password" value="${jdbc.password}"/>
    <property name="url" value="${jdbc.url}"/>
    <property name="driverClassName" value="${jdbc.driverClass}"/>
</bean>

<bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
    <property name="dataSource" ref="dataSource"/>
</bean>

<bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
    <property name="dataSource" ref="dataSource"/>
</bean>
<tx:annotation-driven transaction-manager="transactionManager"/>

<aop:config>
    <aop:advisor advice-ref="txAdvice" pointcut="execution(* com.alamide.spring6.jdbc.*ServiceImpl.*(..))"/>
</aop:config>
<tx:advice id="txAdvice" transaction-manager="transactionManager">
    <tx:attributes>
        <tx:method name="get*" read-only="true"/>
        <tx:method name="query*" read-only="true"/>
        <tx:method name="save*" read-only="false" propagation="REQUIRES_NEW"/>
        <tx:method name="update*" read-only="false" rollback-for="java.lang.Exception" propagation="REQUIRES_NEW"/>
        <tx:method name="delete*" read-only="false" rollback-for="java.lang.Exception" propagation="REQUIRES_NEW"/>
    </tx:attributes>
</tx:advice>

3.Resource

包路径是 org.springframework.core.io.Resource

UrlResource ，loadUrlResources("http://www.zhaosiyuan.com"); ，访问网络资源
ClassPathResource ，loadClasspathResource("beans.xml"); ，访问类路径下文件
FileSystemResource ，loadFileSystemResource("pom.xml"); ，相对路径，当前文件夹

public void loadClasspathResource(String fileName) throws IOException {
    ClassPathResource resource = new ClassPathResource(fileName);
    log.info(resource.getFilename());
    log.info(resource.getDescription());
    BufferedReader buffer = new BufferedReader(new InputStreamReader(resource.getInputStream()));
    buffer.lines().forEach(log::info);
    buffer.close();
}

3.1 ResourceLoader

//获取类路径下的文件
ApplicationContext applicationContext = new ClassPathXmlApplicationContext();
final Resource resource = applicationContext.getResource("beans.xml");

//获取文件系统中文件
ApplicationContext applicationContext = new FileSystemXmlApplicationContext();
final Resource resource = applicationContext.getResource("pom.xml");

//依据前缀，选择使用的 Resource
final Resource resource = applicationContext.getResource("classpath:beans.xml");
final Resource resource = applicationContext.getResource("file:beans.xml");
final Resource resource = applicationContext.getResource("http://www.zhaosiyuan.com");

3.2 classpath 通配符使用

classpath*:beans.xml 搜索所有名为 beans.xml 文件，最后合并成一个 ApplicationContext，如果是 classpath*:beans.xml 则只会加载第一个符合的 XML 文件

ApplicationContext ctx = new ClassPathXmlApplicationContext("classpath*:beans.xml");

加载多个配置文件，以 bean 开头的 XML

ApplicationContext ctx = new ClassPathXmlApplicationContext("classpath:bean*.xml");

可以结合使用

ApplicationContext ctx = new ClassPathXmlApplicationContext("classpath*:bean*.xml");

Tags: Java - Spring - SpringFramework

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