Java 托管人； 私人最终客户映射客户映射； @凌驾 @交易的 公共页getAll（可分页可分页）{ List dbCustomers=customerRepository.findAll（）； List listCustomers=null； dbCustomers.forEach（dbCustomer->{ 添加（customerMapper.toRsDto（dbCustomer））； }); Page rsCustomers=新的PageImpl（列表客户）； 回报客户； } }

依赖于

客户服务的
客户服务mpl
似乎不正确。
从共享代码片段来看，似乎
customerserviceinpl
是
CustomerService
的唯一实现，因此它依赖于
CustomerService
类型的bean是不正确的。这似乎是它首先抱怨日志中存在循环依赖的原因

看来意图是,

依赖于
CustomerRepository
从
CustomerRepository
CustomerServiceImpl
应该更改为依赖于
CustomerRepository
我天真地认为，得益于Spring引导的魔力，getAll可以调用findAll。现在我返回的可能是正确的对象。但这没用。在此之前，我也只是尝试将null返回给getAll。对代码的更改标记在问题标题中。@HtmlMan，我建议查看代码。更新后的代码使用分配给
null
的
listCustomers
。当尝试添加
客户时，更新的代码现在应该抛出
NullPointerException
。代码还在
CustomerRepository
上执行
findAll
，如果有大量客户，这可能会有问题，因为它将尝试获取内存中的所有内容。Spring提供了很好的文档，因此请参考Spring.io/learn和。
public interface CustomerRepository extends JpaRepository<Customer, Long> {}

public interface CustomerService {
    Page<CustomerRsDto> getAll(Pageable pageable);
}

@Service
@RequiredArgsConstructor
public class CustomerServiceImpl implements CustomerService {
    private final CustomerService customerService;
    
    @Override
    @Transactional
    public Page<CustomerRsDto> getAll(Pageable pageable) {
        Page<CustomerRsDto> rsCustomers = customerService.getAll(pageable);
        return rsCustomers;
    }
}

@RestController
@RequiredArgsConstructor
@RequestMapping("/customers")
@Api(tags = "customers", value = "Customres")
public class CustomersController {
    private CustomerService customerService;

    @GetMapping
    @ApiOperation(tags = "customers", value = "Get all")
    public Page<CustomerRsDto> getAll(Pageable pageable) {
        if (isNull(customerService)) {
            System.out.println("Not linked bean?");
        }
        return customerService.getAll(pageable);
    }
}

WARN 8928 --- [main] ConfigServletWebServerApplicationContext : Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'customerServiceImpl' defined in file [<My Patch>\service\impl\CustomerServiceImpl.class]: Unsatisfied dependency expressed through constructor parameter 0; nested exception is org.springframework.beans.factory.BeanCurrentlyInCreationException: Error creating bean with name 'customerServiceImpl': Requested bean is currently in creation: Is there an unresolvable circular reference?

ERROR 8928 --- [main] o.s.b.d.LoggingFailureAnalysisReporter: 

***************************
APPLICATION FAILED TO START
***************************

Description:

The dependencies of some of the beans in the application context form a cycle:

┌─────┐
|  customerServiceImpl defined in file [<My Patch>\service\impl\CustomerServiceImpl.class]
└─────┘

Process finished with exit code 1

@Service
public class CustomerServiceImpl implements CustomerService {
    private final CustomerService customerService;

    public CustomerServiceImpl(@Lazy CustomerService customerService) {
        super();
        this.customerService = customerService;
    }

    @Override
    @Transactional
    public Page<CustomerRsDto> getAll(Pageable pageable) {
        Page<CustomerRsDto> rsCustomers = customerService.getAll(pageable);
        return rsCustomers;
    }
}

2020-11-11 17:59:29.826  INFO 1236 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : Completed initialization in 7 ms
Not linked bean?
2020-11-11 17:59:30.308 ERROR 1236 --- [nio-8080-exec-1] o.a.c.c.C.[.[.[/].[dispatcherServlet]    : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is java.lang.NullPointerException] with root cause

java.lang.NullPointerException: null
    at <My Package>.rest.CustomersController.getAll(CustomersController.java:31) ~[classes/:na]
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:na]
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
    at java.base/java.lang.reflect.Method.invoke(Method.java:566) ~[na:na]
    at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:190) ~[spring-web-5.2.10.RELEASE.jar:5.2.10.RELEASE]
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:138) ~[spring-web-5.2.10.RELEASE.jar:5.2.10.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:105) ~[spring-webmvc-5.2.10.RELEASE.jar:5.2.10.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:878) ~[spring-webmvc-5.2.10.RELEASE.jar:5.2.10.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:792) ~[spring-webmvc-5.2.10.RELEASE.jar:5.2.10.RELEASE]
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.2.10.RELEASE.jar:5.2.10.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1040) ~[spring-webmvc-5.2.10.RELEASE.jar:5.2.10.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:943) ~[spring-webmvc-5.2.10.RELEASE.jar:5.2.10.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) ~[spring-webmvc-5.2.10.RELEASE.jar:5.2.10.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898) ~[spring-webmvc-5.2.10.RELEASE.jar:5.2.10.RELEASE]

@Service
@RequiredArgsConstructor
public class CustomerServiceImpl implements CustomerService {
    private final CustomerRepository customerRepository;
    private final CustomerMapper customerMapper;

    @Override
    @Transactional
    public Page<CustomerRsDto> getAll(Pageable pageable) {
        List<Customer> dbCustomers = customerRepository.findAll();
        List<CustomerRsDto> listCustomers = null;

        dbCustomers.forEach(dbCustomer -> {
            listCustomers.add(customerMapper.toRsDto(dbCustomer));
        });

        Page<CustomerRsDto> rsCustomers = new PageImpl<CustomerRsDto>(listCustomers);

        return rsCustomers;
    }
}