Java 在Spring Boot 2.3中再现Spring数据Rest搜索控制器

在SpringBoot2.0之前，我可以重现为mongodb存储库公开的查询方法生成的控制器。 下面是一个代码示例：

域实体

@Document(collection = "foos")
public class Foo {
    @Id
    private String id;
    private String name;

    // getters/setters omitted
}

Mongo存储库

public interface FooRepository extends MongoRepository<Foo, String> {

    public Page<Foo> findByName(@Param("name") String name, Pageable pageable);

}

我可以用以下自定义控制器和配置复制它

@RestController
@RequestMapping("foos")
@RequiredArgsConstructor // lombok
public class FooQueryController {

    private final FooRepository repository;
    private final PagedResourcesAssembler pagedResourcesAssembler;

    @GetMapping(value = "search/query",
                produces = MediaType.APPLICATION_JSON_UT8_VALUE)
    public ResponseEntity custom(@RequestParam("name") String name,
                                      Pageable pageable,
                                      PersistentEntityResourceAssembler resourceAssembler) {
        var page = repository.findByName(name, pageable);
        var model = pagedResourcesAssembler.toResource(page, resourceAssembler);

        return ResponseEntity.ok(model);
    }

}

// Enables injecting a PersistentEntityResourceAssembler  in a RestController
// see https://jira.spring.io/browse/DATAREST-657 for details
@Configuration
@Order(Ordered.HIGHEST_PRECEDENCE)
@RequiredArgsConstructor
public class MvcConfiguration implements WebMvcConfigurer {

    // WARNING: do NOT change the name of this member - it is injected with the
    //          RequestMappingHandlerAdapter$repositoryExporterHandlerAdapter().
    private final RequestMappingHandlerAdapter repositoryExporterHandlerAdapter;

    @Override
    public void addArgumentResolvers(
            List<HandlerMethodArgumentResolver> argumentResolvers) {
        List<HandlerMethodArgumentResolver> customArgumentResolvers =
                repositoryExporterHandlerAdapter.getCustomArgumentResolvers();
        argumentResolvers.addAll(customArgumentResolvers);
    }

}

在控制器中使用Spring HATEOAS 1.0 API切换到Spring Boot 2.3

@RestController
@RequestMapping("foos")
@RequiredArgsConstructor
public class FooQueryController {

    private final FooRepository repository;
    private final PagedResourcesAssembler pagedResourcesAssembler;

    @GetMapping(value = "search/query",
                produces = MediaType.APPLICATION_JSON_VALUE)
    public ResponseEntity custom(@RequestParam("name") String name,
                                      Pageable pageable,
                                      PersistentEntityResourceAssembler resourceAssembler) {
        var page = repository.findByName(name, pageable);
        var model = pagedResourcesAssembler.toModel(page, resourceAssembler);

        return ResponseEntity.ok(model);
    }

}

我现在得到以下结果：

{"_embedded":{"foos":[{"id":"56a8a8d5daffd28c9c907974","name":"qc","embeddeds":{},"nested":false,"persistentEntity":{"idProperty":{"name":"id","rawType":"java.lang.String","association":false,"owner":{"idProperty":{"name":"id","rawType":"java.lang.String","association":false,"owner":{"idProperty":{"name":"id","rawType":"java.lang.String","association":false,"owner":{"idProperty":{"name":"id","rawType":"java.lang.String","association":false,"owner":{"idProperty":{"name":"id","rawType":"java.lang.String","association":false,"owner":{"idProperty":{"name":"id","rawType":"java.lang.String","association":false,"owner":{"idProperty":{"name":"id","rawType":"java.lang.String","association":false,"owner":{"idProperty":{"name":"id","rawType":"java.lang.String","association":false,"owner":{"idProperty":{"name":"id","rawType":"java.lang.String","association":false,"owner":{"idProperty":{"name":"id","rawType":"java.lang.String","association":false,"owner":{"idProperty":

{"content":[{"id":"56a8a8d5daffd28c9c907974","name":"qc"}],"pageable":{"sort":{"sorted":false,"unsorted":true,"empty":true},"offset":0,"pageNumber":0,"pageSize":20,"paged":true,"unpaged":false},"last":true,"totalPages":1,"totalElements":1,"size":20,"number":0,"sort":{"sorted":false,"unsorted":true,"empty":true},"numberOfElements":1,"first":true,"empty":false}

Spring日志中有以下错误：

2020-08-06 18:11:20.968  WARN 9932 --- [nio-8080-exec-1] .w.s.m.s.DefaultHandlerExceptionResolver : Failure while trying to resolve exception [org.springframework.http.converter.HttpMessageNotWritableException]

java.lang.IllegalStateException: Cannot call sendError() after the response has been committed
    at org.apache.catalina.connector.ResponseFacade.sendError(ResponseFacade.java:472) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
    at org.springframework.web.servlet.mvc.support.DefaultHandlerExceptionResolver.sendServerError(DefaultHandlerExceptionResolver.java:550) ~[spring-webmvc-5.2.8.RELEASE.jar:5.2.8.RELEASE]
    at org.springframework.web.servlet.mvc.support.DefaultHandlerExceptionResolver.handleHttpMessageNotWritable(DefaultHandlerExceptionResolver.java:440) ~[spring-webmvc-5.2.8.RELEASE.jar:5.2.8.RELEASE]
    at org.springframework.web.servlet.mvc.support.DefaultHandlerExceptionResolver.doResolveException(DefaultHandlerExceptionResolver.java:210) ~[spring-webmvc-5.2.8.RELEASE.jar:5.2.8.RELEASE]
    at org.springframework.web.servlet.handler.AbstractHandlerExceptionResolver.resolveException(AbstractHandlerExceptionResolver.java:141) ~[spring-webmvc-5.2.8.RELEASE.jar:5.2.8.RELEASE]
    at org.springframework.web.servlet.handler.HandlerExceptionResolverComposite.resolveException(HandlerExceptionResolverComposite.java:80) ~[spring-webmvc-5.2.8.RELEASE.jar:5.2.8.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.processHandlerException(DispatcherServlet.java:1300) ~[spring-webmvc-5.2.8.RELEASE.jar:5.2.8.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:1111) ~[spring-webmvc-5.2.8.RELEASE.jar:5.2.8.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1057) ~[spring-webmvc-5.2.8.RELEASE.jar:5.2.8.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:943) ~[spring-webmvc-5.2.8.RELEASE.jar:5.2.8.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) ~[spring-webmvc-5.2.8.RELEASE.jar:5.2.8.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898) ~[spring-webmvc-5.2.8.RELEASE.jar:5.2.8.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:626) ~[tomcat-embed-core-9.0.37.jar:4.0.FR]
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) ~[spring-webmvc-5.2.8.RELEASE.jar:5.2.8.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:733) ~[tomcat-embed-core-9.0.37.jar:4.0.FR]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-9.0.37.jar:9.0.37]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
    at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) ~[spring-web-5.2.8.RELEASE.jar:5.2.8.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.8.RELEASE.jar:5.2.8.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
    at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) ~[spring-web-5.2.8.RELEASE.jar:5.2.8.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.8.RELEASE.jar:5.2.8.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) ~[spring-web-5.2.8.RELEASE.jar:5.2.8.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.8.RELEASE.jar:5.2.8.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:373) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1589) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
    at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) ~[na:na]
    at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) ~[na:na]
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
    at java.base/java.lang.Thread.run(Thread.java:834) ~[na:na]

2020-08-06 18:11:20.979 ERROR 9932 --- [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 org.springframework.http.converter.HttpMessageNotWritableException: Could not write JSON: Infinite recursion (StackOverflowError); nested exception is com.fasterxml.jackson.databind.JsonMappingException: Infinite recursion (StackOverflowError) (through reference chain: org.springframework.data.mongodb.core.mapping.CachingMongoPersistentProperty["owner"]->org.springframework.data.mongodb.core.mapping.BasicMongoPersistentEntity["idProperty"]->org.springframework.data.mongodb.core.mapping.CachingMongoPersistentProperty["owner"]->org.springframework.data.mongodb.core.mapping.BasicMongoPersistentEntity["idProperty"]->org.springframework.data.mongodb.core.mapping.CachingMongoPersistentProperty["owner"]->org.springframework.data.mongodb.core.mapping.BasicMongoPersistentEntity["idProperty"]->org.springframework.data.mongodb.core.mapping.CachingMongoPersistentProperty["owner"]->org.springframework.data.mongodb.core.mapping.BasicMongoPersistentEntity["idProperty"]->org.springframework.data.mongodb.core.mapping.CachingMongoPersistentProperty["owner"]->org.springframework.data.mongodb.core.mapping.BasicMongoPersistentEntity["idProperty"]-> ... IT GOES ON AND ON LIKE THIS ... ->org.springframework.data.mongodb.core.mapping.BasicMongoPersistentEntity["idProperty"])] with root cause

java.lang.StackOverflowError: null
    at java.base/java.lang.ClassLoader.defineClass1(Native Method) ~[na:na]
    at java.base/java.lang.ClassLoader.defineClass(ClassLoader.java:1016) ~[na:na]
    at java.base/java.security.SecureClassLoader.defineClass(SecureClassLoader.java:174) ~[na:na]
    at java.base/jdk.internal.loader.BuiltinClassLoader.defineClass(BuiltinClassLoader.java:800) ~[na:na]
    at java.base/jdk.internal.loader.BuiltinClassLoader.findClassOnClassPathOrNull(BuiltinClassLoader.java:698) ~[na:na]
    at java.base/jdk.internal.loader.BuiltinClassLoader.loadClassOrNull(BuiltinClassLoader.java:621) ~[na:na]
    at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:579) ~[na:na]
    at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:178) ~[na:na]
    at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521) ~[na:na]
    at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:773) ~[jackson-databind-2.11.1.jar:2.11.1]
    at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:178) ~[jackson-databind-2.11.1.jar:2.11.1]
    at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:728) ~[jackson-databind-2.11.1.jar:2.11.1]
    at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:755) ~[jackson-databind-2.11.1.jar:2.11.1]
    at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:178) ~[jackson-databind-2.11.1.jar:2.11.1]

    ... IT GOES ON LIKE THIS FOR DOZENS AND DOZENS OF LINE

    at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:728) ~[jackson-databind-2.11.1.jar:2.11.1]
    at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:755) ~[jackson-databind-2.11.1.jar:2.11.1]

2020-08-06 18:11:21.553 ERROR 9932 --- [nio-8080-exec-1] s.e.ErrorMvcAutoConfiguration$StaticView : Cannot render error page for request [/foos/search/query] and exception [] as the response has already been committed. As a result, the response may have the wrong status code.

如果返回

var page=repository.findByName（名称，可分页）的内容而不是
var model=pagedResourcesAssembler.toModel（页面，resourceAssembler），我得到以下结果：

{"_embedded":{"foos":[{"id":"56a8a8d5daffd28c9c907974","name":"qc","embeddeds":{},"nested":false,"persistentEntity":{"idProperty":{"name":"id","rawType":"java.lang.String","association":false,"owner":{"idProperty":{"name":"id","rawType":"java.lang.String","association":false,"owner":{"idProperty":{"name":"id","rawType":"java.lang.String","association":false,"owner":{"idProperty":{"name":"id","rawType":"java.lang.String","association":false,"owner":{"idProperty":{"name":"id","rawType":"java.lang.String","association":false,"owner":{"idProperty":{"name":"id","rawType":"java.lang.String","association":false,"owner":{"idProperty":{"name":"id","rawType":"java.lang.String","association":false,"owner":{"idProperty":{"name":"id","rawType":"java.lang.String","association":false,"owner":{"idProperty":{"name":"id","rawType":"java.lang.String","association":false,"owner":{"idProperty":{"name":"id","rawType":"java.lang.String","association":false,"owner":{"idProperty":

{"content":[{"id":"56a8a8d5daffd28c9c907974","name":"qc"}],"pageable":{"sort":{"sorted":false,"unsorted":true,"empty":true},"offset":0,"pageNumber":0,"pageSize":20,"paged":true,"unpaged":false},"last":true,"totalPages":1,"totalElements":1,"size":20,"number":0,"sort":{"sorted":false,"unsorted":true,"empty":true},"numberOfElements":1,"first":true,"empty":false}

因此，循环混乱来自序列化
pagedResourcesAssembler.toModel（页面，resourceAssembler）
（可能还有WebMVCConfiguer覆盖）。
调用
PersistentEntityResourcesAssembler.toModel（对象）
时，我有相同的
StackOverflower:null
。我的代码返回单个
EntityModel
，而不是
PagedModel
。通过切换到
PersistentEntityResourcesAssembler.toFullResource（对象）
解决了我的问题

toModel（对象）
使用摘录投影，而
toFullResource（对象）
不使用。我没有时间深入研究代码来检查是什么产生了无限循环，从而导致堆栈溢出

查看
PagedResourcesAssembler
，
PagedResourcesAssembler.toModel（页面，RepresentationModelAssembler）
调用
RepresentationModelAssember.toModel（对象）

因此，解决方法1是复制
PagedResourcesAssembler.toModel（页面，RepresentationModelAssembler）
的源代码，并使用
RepresentationModelAssember.toFullResource（对象）

解决方法2是扩展
PagedResourcesAssembler
并重写
createModel（…）
方法

在进行变通之前，我有一个问题。为什么要将
PersistentEntityResourcesAssembler
传递到
PagedResourcesAssembler
？当我的自定义控制器返回单个资源时，我的代码使用
PersistentEntityResourcesAssembler
添加HTTP头
ETag
和
Last Modified
。使用PersistentEntityResourcesAssembler构建集合资源（分页资源）的响应有什么好处？
多亏了，我能够：


将控制器
多值映射
参数转换为
谓词
使用
RepositoryRestController
而不是
RestController
，即能够将
persistenentEntityResourcesAssembler
注入控制器方法

如公认答案中所建议的，定制模型和模型汇编程序是不必要的

配置
querydsldpredicatebuilder
bean：

@Configuration
@RequiredArgsConstructor
public class QueryDslConfiguration {

    private final ConversionService mvcConversionService;
    private final QuerydslBindingsFactory querydslBindingsFactory;

    @Bean
    public QuerydslPredicateBuilder querydslPredicateBuilder() {
        return new QuerydslPredicateBuilder(mvcConversionService, querydslBindingsFactory.getEntityPathResolver());
    }

}

将多值映射转换为谓词的服务：

@Service
@RequiredArgsConstructor(onConstructor = @__(@Autowired))
public class PredicateService {

    private final QuerydslPredicateBuilder querydslPredicateBuilder;
    private final QuerydslBindingsFactory querydslBindingsFactory;

    public <T> Predicate getPredicateFromParameters(final MultiValueMap<String, String> parameters, Class<T> tClass) {
        TypeInformation<T> typeInformation = ClassTypeInformation.from(tClass);
        return querydslPredicateBuilder.getPredicate(typeInformation,
                parameters,
                querydslBindingsFactory.createBindingsFor(typeInformation));
    }
}

@服务
@RequiredArgsConstructor（onConstructor=@_u（@Autowired））
公共类谓词服务{
专用最终QuerydslPredicateBuilder QuerydslPredicateBuilder；
私有最终QuerydslBindingsFactory QuerydslBindingsFactory；
公共谓词getPredicateFromParameters（最终多值映射参数，类tClass）{
TypeInformation-TypeInformation=ClassTypeInformation.from（tClass）；
返回querydslPredicateBuilder.getPredicate（类型信息，
参数，
createBindingsFor（类型信息））；
}
}

在控制器中使用转换器：

@RepositoryRestController
@RequiredArgsConstructor
public class FooController {

    private final FooRepository repository;
    private final PredicateService predicateService;

    @GetMapping("/foos/search/query")
    public PagedModel<Foo> query(
            @RequestParam MultiValueMap<String, String> parameters,
            Pageable pageable,
            PersistentEntityResourceAssembler resourceAssembler) {
        Predicate predicate = predicateService.getPredicateFromParameters(parameters, Foo.class);
        Page<Parameter> page = repository.findAll(predicate, 

        return pagedResourcesAssembler.toModel(page, resourceAssembler);
    }

}

@RepositoryRestController
@所需参数构造函数
公共类FooController{
私有最终存储库；
私有最终谓词服务谓词服务；
@GetMapping（“/foos/search/query”）
公共页面模型查询(
@RequestParam多值映射参数，
可分页可分页，
PersistentEntityResourcesAssembler（资源汇编程序）{
谓词谓词=谓词服务.getPredicateFromParameters（参数，Foo.class）；
Page=repository.findAll（谓词，
返回pagedResourcesAssembler.toModel（页面，resourceAssembler）；
}
}
PagedResourcesAssembler
使用给定的resourceassembler将页面的每个元素转换为资源（具有自己的链接集）。使用
PersistentEntityResourcesAssembler
允许我为每个域实体定义自定义控制器，而无需为每个域类定义我的a汇编器。这样，我的控制器的响应格式与Spring生成的控制器的响应格式一致。请理解，您希望编写更少的
RepresentationModelAssembler
。但是编写汇编程序比我的回答中描述的黑客解决方法更优雅。：）RepresentationModelAssember:：toFullResource没有帮助，但是使用自定义汇编程序工作得很好。谢谢