Jpa与Druid线程池及Spring Boot整合(二): spring-boot-starter-data-jpa 踏坑异常处理方案

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 Jpa与Druid线程池及Spring Boot整合(一)

Jpa与Druid线程池及Spring Boot整合(二)：几个坑

附录官网文档：core.domain-events域事件

从聚合根发布事件

class AnAggregateRoot {

    @DomainEvents (1)
    Collection<Object> domainEvents() {
        // … return events you want to get published here
    }

    @AfterDomainEventPublication (2)
    void callbackMethod() {
       // … potentially clean up domain events list
    }
}

在使用Spring Boot JPA时，open-in-view 选项默认为true。启动时在日志中会出现警告。 

一坑：druid与jpa整合，启动出现如下警告：

JpaBaseConfiguration$JpaWebConfiguration : spring.jpa.open-in-view is enabled by default. Therefore, database queries may be performed during view rendering. Explicitly configure spring.jpa.open-in-view to disable this warning

 处理方案:

按照日志要求将 open-in-view=false。再次启动，如果在实体类中外键字段使用了懒加载模式，在视图层中调用数据时，则会出现 no session 异常。

解决方法：手动注册OpenEntityManagerInViewFilter过滤器，改变session的生命周期，当web请求关闭时才结束session。
 

  javaConfig注入bean

@Bean
public FilterRegistrationBean<OpenEntityManagerInViewFilter> registerOpenEntityManagerInViewFilterBean() {
    FilterRegistrationBean<OpenEntityManagerInViewFilter> registrationBean = new FilterRegistrationBean<>();
    OpenEntityManagerInViewFilter filter = new OpenEntityManagerInViewFilter();
    registrationBean.setFilter(filter);
    registrationBean.setOrder(5);
    return registrationBean;
}

解疑：

如果使用的是 JPA 则对应OpenEntityManagerInViewFilter,Hibernate对应OpenSessionInViewFilter
疑问：

registrationBean.setOrder(5)，order为什么是5
OpenSessionInViewInterceptor&OpenSessionInViewFilter,OpenEntityManagerInViewInterceptor&OpenEntityManagerInViewFilter这几个类的区别以及使的的场景
 

---

重新启动: 正常：

二坑:   springboot整合JPA出现异常java.lang.IllegalArgumentException: Not a managed type: class xx

方案: 一

启动类或者JavaConfig添加添加扫描实体的路径:
@EntityScan(basePackages = "org.jd.websocket.auth.data.reactor.jpa")
@EnableTransactionManagement // 开启事务的支持
@EnableJpaRepositories(basePackages = {"org.jd.websocket.auth.data.reactor.repository","org.jd.websocket.auth.data.reactor.jpa"},
        includeFilters = {@ComponentScan.Filter(type = FilterType.REGEX, pattern = ".*CrudRepository")},
        excludeFilters = {@ComponentScan.Filter(type = FilterType.REGEX, pattern = ".*SomeOtherRepository")})

 方案: 二

@Configuration     javaConfig中注入Bean

@Bean
public LocalContainerEntityManagerFactoryBean entityManagerFactory() {
    HibernateJpaVendorAdapter vendorAdapter = new HibernateJpaVendorAdapter();
    vendorAdapter.setGenerateDdl(true);
    LocalContainerEntityManagerFactoryBean factory = new LocalContainerEntityManagerFactoryBean();
    factory.setJpaVendorAdapter(vendorAdapter);
    // entity扫描的包路径
    factory.setPackagesToScan("org.jd.websocket.auth.data.reactor.jpa");
    factory.setDataSource(dataSource());
    return factory;
}

---

@Value("${spring.datasource.url}")
private String dbUrl;

@Value("${spring.datasource.username}")
private String username;
@Value("${spring.datasource.password}")
private String password;
@Value("${spring.datasource.driver-class-name}")
private String driverClassName;

@Value("${spring.datasource.initialSize}")
private int initialSize;
@Value("${spring.datasource.minIdle}")
private int minIdle;
@Value("${spring.datasource.maxActive}")
private int maxActive;
@Value("${spring.datasource.maxWait}")
private int maxWait;
@Value("${spring.datasource.timeBetweenEvictionRunsMillis}")
private int timeBetweenEvictionRunsMillis;
@Value("${spring.datasource.minEvictableIdleTimeMillis}")
private int minEvictableIdleTimeMillis;
@Value("${spring.datasource.validationQuery}")
private String validationQuery;
@Value("${spring.datasource.testWhileIdle}")
private boolean testWhileIdle;
@Value("${spring.datasource.testOnBorrow}")
private boolean testOnBorrow;
@Value("${spring.datasource.testOnReturn}")
private boolean testOnReturn;
@Value("${spring.datasource.poolPreparedStatements}")
private boolean poolPreparedStatements;
@Value("${spring.datasource.maxPoolPreparedStatementPerConnectionSize}")
private int maxPoolPreparedStatementPerConnectionSize;
@Value("${spring.datasource.filters}")
private String filters;
@Value("{spring.datasource.connectionProperties}")
private String connectionProperties;

@Bean
@Primary
public DataSource dataSource() {
    DruidDataSource datasource = new DruidDataSource();
    datasource.setUrl(dbUrl);
    datasource.setUsername(username);
    datasource.setPassword(password);
    datasource.setDriverClassName(driverClassName);
    // configuration
    datasource.setInitialSize(initialSize);
    datasource.setMinIdle(minIdle);
    datasource.setMaxActive(maxActive);
    datasource.setMaxWait(maxWait);
    datasource.setTimeBetweenEvictionRunsMillis(timeBetweenEvictionRunsMillis);
    datasource.setMinEvictableIdleTimeMillis(minEvictableIdleTimeMillis);
    datasource.setValidationQuery(validationQuery);
    datasource.setTestWhileIdle(testWhileIdle);
    datasource.setTestOnBorrow(testOnBorrow);
    datasource.setTestOnReturn(testOnReturn);
    datasource.setPoolPreparedStatements(poolPreparedStatements);
    datasource.setMaxPoolPreparedStatementPerConnectionSize(maxPoolPreparedStatementPerConnectionSize);
    try {
        datasource.setFilters(filters);
    } catch (SQLException e) {
        System.err.println("druid configuration initialization filter: " + e);
    }
    datasource.setConnectionProperties(connectionProperties);
    return datasource;
}

@Bean
public LocalContainerEntityManagerFactoryBean entityManagerFactory() {
    HibernateJpaVendorAdapter vendorAdapter = new HibernateJpaVendorAdapter();
    vendorAdapter.setGenerateDdl(true);
    LocalContainerEntityManagerFactoryBean factory = new LocalContainerEntityManagerFactoryBean();
    factory.setJpaVendorAdapter(vendorAdapter);
    // entity扫描的包路径
    factory.setPackagesToScan("org.jd.websocket.auth.data.reactor.jpa");
    factory.setDataSource(dataSource());
    return factory;
}

坑三:    多数据源注入,事务失效|解决方案;

* @Transactiona在多数据源下失效
* 在多数据源的情况下，如果transactionManager进行了分开配置，比如这里针对三个数据源配置了三个transactionManager
* ===========================================================================================================
* @Bean("formTransactionManager")
* public PlatformTransactionManager transactionManager(EntityManagerFactoryBuilder builder) {
*     return new JpaTransactionManager(Objects.requireNonNull(entityManagerFactory(builder).getObject()));
* }
*=============================================================================================================
* @Bean("fileTransactionManager")
* public PlatformTransactionManager transactionManager(EntityManagerFactoryBuilder builder) {
*     return new JpaTransactionManager(Objects.requireNonNull(entityManagerFactory(builder).getObject()));
* }
* ============================================================================================================
* @Primary
* @Bean("userTransactionManager")
* public PlatformTransactionManager transactionManager(EntityManagerFactoryBuilder builder) {
*     return new JpaTransactionManager(Objects.requireNonNull(entityManagerFactory(builder).getObject()));
* }
* =============================================================================================================
*
* 那么在使用@Transactional的时候需要指定transactionManager
* @Transactional("formTransactionManager")

---

@EnableTransactionManagement // 开启事务的支持

可以访问下druid监控相关数据:

http://localhost:9999/druid/

输入上面的账号和密码:  可以查看不同的选项卡,能帮助我们排查一些数据库相关问题

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