小编Hol*_*ncy的帖子

我使用spring boot version"1.3.0.M5"(我也试过版本"1.2.5.RELEASE").我添加了弹簧安全性:

<dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
  <groupId>org.springframework.security</groupId>
  <artifactId>spring-security-test</artifactId>
  <scope>test</scope>
</dependency>

和代码:

@SpringBootApplication
public class SpringBootMainApplication {
  public static void main(String[] args) {
    SpringApplication.run(SpringBootMainApplication.class, args);
  }
}

@Configuration
@EnableWebSecurity
public class WebSecurityConfiguration extends WebSecurityConfigurerAdapter {
  @Override
  protected void configure(AuthenticationManagerBuilder auth) throws Exception {
  auth.inMemoryAuthentication().withUser("user").password("password").roles("USER");
  }
  @Override
  protected void configure(HttpSecurity http) throws Exception {
    http.authorizeRequests()
    .antMatchers("/api/sampleentity").authenticated()
    .and().authorizeRequests()
    .and().formLogin().permitAll()
    .and().logout().permitAll().logoutUrl("/logout")
    .logoutSuccessUrl("/");
  }
  @Override
  @Bean
  public AuthenticationManager authenticationManagerBean() throws Exception {
    return super.authenticationManagerBean();
  }
}

@RestController
@RequestMapping("/api/sampleentity")
public class SampleEntityController {
  @RequestMapping(method= …

我想从 PostgreSQL 11.2 流式传输结果，而不是一次将所有结果读取到内存中。我使用最新的稳定版 SpringBoot 2.1.4.RELEASE。

我阅读了如何在 MySQL 中执行此操作的文章。 http://knes1.github.io/blog/2015/2015-10-19-streaming-mysql-results-using-java8-streams-and-spring-data.html 我还阅读了如何在 PostgreSQL 中执行此操作的文章： Postgresql 中的 Java 8 JPA 存储库流逐行

我有这样的存储库：

public interface ProductRepository extends JpaRepository<Product, UUID> {
    @Query("SELECT p from Product p")
    @QueryHints(value = @QueryHint(name = HINT_FETCH_SIZE, value = "50"))
    Stream<Product> streamAll();
}

比我这样使用流：

  productRepository.streamAll().forEach(product -> export(product));

为了使示例更简单，'export' 方法完全为空。

当我调用该方法时，我看到 Hibernate 查询

Hibernate: select product0_.id as id1_0_, product0_.created as created2_0_, product0_.description as descript3_0_, product0_.name as name4_0_, product0_.product_type_id as product_5_0_ from products product0_ order by product0_.id

一段时间后，我出现了 OutOfMemoryError。查询提示没有帮助。

如何使用 Spring Boot …

我想在我的Spring Boot 4应用程序中添加缓存.作为一个键,我想使用我的实体的id(类型Long),值是我的实体.

@EnableCaching
@SpringBootApplication
public class SpringBootMainApplication {
  public static void main(String[] args) {
    SpringApplication.run(SpringBootMainApplication.class, args);
  }
}

@Configuration
public class AppConfiguration {
  @Bean
  public CacheManager cacheManager() {
    return new ConcurrentMapCacheManager("findOne");
  }
}

public interface SampleEntityService extends CrudRepository<SampleEntity, Long> {
  @Cacheable(key = "#a0", value = "findOne")
  SampleEntity findOne(Long id);

但是当我在测试中调用findOne方法时,我得到了一个异常:

java.lang.ClassCastException: org.springframework.cache.support.SimpleValueWrapper cannot be cast to my.springboot.model.SampleEntity
  at my.springboot.SampleEntityCacheTest.aaa(SampleEntityCacheTest.java:46)
  at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
  at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
  at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
  at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
  at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
  at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
  at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
  at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
  at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:73)
  at …

在AWS lambda函数（用Java编写）中我想使用AsyncHttpClient（https://github.com/AsyncHttpClient/async-http-client). Unfortunately it takes around 500 ms to create an instance of this object.. (but I still like it, please don't advice me to change the http client).

我正在考虑在静态初始化块中创建 AsyncHttpClient 。因此，它可能会由 AWS 执行一次，并且每次 AWS Lambda 执行都会克隆快照。我对么 ？

何时在 AWS Lambda 中执行静态块？

• 一旦快照被克隆到每个 AWS Lambda 调用
• 或者为每个 Lambda 执行单独执行静态块（并且将 Http Client 的创建放在那里没有帮助）

谢谢你的帮助