Spring Boot Actuator端点JSON解析错误排查求助

环境信息 #

• Spring Boot 2.7.6
• Spring Cloud 2021.0.3

问题现象 #

4个Spring Boot服务中，其中一个无法访问Actuator的/info端点，访问地址为http://localhost:8314/gdelt-mapper/info，返回400 Bad Request错误，核心报错为JSON解析失败：无法将数组类型反序列化为LinkedHashMap<String,String>。

核心错误栈 #

org.springframework.http.converter.HttpMessageNotReadableException: JSON parse error: Cannot deserialize value of type `java.util.LinkedHashMap<java.lang.String,java.lang.String>` from Array value (token `JsonToken.START_ARRAY`); nested exception is com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot deserialize value of type `java.util.LinkedHashMap<java.lang.String,java.lang.String>` from Array value (token `JsonToken.START_ARRAY`)
    at [Source: (org.springframework.util.StreamUtils$NonClosingInputStream); line: 1, column: 1]
    at org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.readJavaType(AbstractJackson2HttpMessageConverter.java:391)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
        at java.base/java.lang.Thread.run(Thread.java:829)
Caused by: com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot deserialize value of type `java.util.LinkedHashMap<java.lang.String,java.lang.String>` from Array value (token `JsonToken.START_ARRAY`)
 at [Source: (org.springframework.util.StreamUtils$NonClosingInputStream); line: 1, column: 1]
    at com.fasterxml.jackson.databind.exc.MismatchedInputException.from(MismatchedInputException.java:59)
    at com.fasterxml.jackson.databind.DeserializationContext.reportInputMismatch(DeserializationContext.java:1741)
    at com.fasterxml.jackson.databind.DeserializationContext.handleUnexpectedToken(DeserializationContext.java:1515)
    at com.fasterxml.jackson.databind.deser.std.StdDeserializer._deserializeFromArray(StdDeserializer.java:222)
    at com.fasterxml.jackson.databind.deser.std.MapDeserializer.deserialize(MapDeserializer.java:447)
    at com.fasterxml.jackson.databind.deser.std.MapDeserializer.deserialize(MapDeserializer.java:32)
    at com.fasterxml.jackson.databind.deser.DefaultDeserializationContext.readRootValue(DefaultDeserializationContext.java:323)
    at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:4674)
    at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:3682)
    at org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.readJavaType(AbstractJackson2HttpMessageConverter.java:380)... 55 more

错误响应JSON #

{
    "timestamp": "2023-05-17T21:26:08.353+00:00",
    "status": 400,
    "error": "Bad Request",
    "trace": "org.springframework.http.converter.HttpMessageNotReadableException: JSON parse error: Cannot deserialize value of type `java.util.LinkedHashMap<java.lang.String,java.lang.String>` from Array value (token `JsonToken.START_ARRAY`); nested exception is com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot deserialize value of type `java.util.LinkedHashMap<java.lang.String,java.lang.String>` from Array value (token `JsonToken.START_ARRAY`)\n at [Source: (org.springframework.util.StreamUtils$NonClosingInputStream); line: 1, column: 1]\r\n\tat org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.readJavaType(AbstractJackson2HttpMessageConverter.java:391)\r\n\tat org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.read(AbstractJackson2HttpMessageConverter.java:343)\r\n\tat org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodArgumentResolver.readWithMessageConverters(AbstractMessageConverterMethodArgumentResolver.java:185)\r\n\tat org.springframework.web.servlet.mvc.method.annotation.RequestResponseBodyMethodProcessor.readWithMessageConverters(RequestResponseBodyMethodProcessor.java:160)\r\n\tat org.springframework.web.servlet.mvc.method.annotation.RequestResponseBodyMethodProcessor.resolveArgument(RequestResponseBodyMethodProcessor.java:133)\r\n\tat org.springframework.web.method.support.HandlerMethodArgumentResolverComposite.resolveArgument(HandlerMethodArgumentResolverComposite.java:122)\r\n\tat org.springframework.web.method.support.InvocableHandlerMethod.getMethodArgumentValues(InvocableHandlerMethod.java:179)\r\n\tat org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:146)\r\n\tat org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:117)\r\n\tat org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:895)\r\n\tat org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:808)\r\n\tat org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)\r\n\tat org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1071)\r\n\tat org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:964)\r\n\tat org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006)\r\n\tat org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898)\r\n\tat javax.servlet.http.HttpServlet.service(HttpServlet.java:670)\r\n\tat org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883)\r\n\tat javax.servlet.http.HttpServlet.service(HttpServlet.java:779)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:227)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)\r\n\tat org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)\r\n\tat org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100)\r\n\tat org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)\r\n\tat org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93)\r\n\tat org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)\r\n\tat org.springframework.boot.actuate.metrics.web.servlet.WebMvcMetricsFilter.doFilterInternal(WebMvcMetricsFilter.java:96)\r\n\tat org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)\r\n\tat org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201)\r\n\tat org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)\r\n\tat org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:177)\r\n\tat org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97)\r\n\tat org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541)\r\n\tat org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:135)\r\n\tat org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)\r\n\tat org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78)\r\n\tat org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:360)\r\n\tat org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:399)\r\n\tat org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)\r\n\tat org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:891)\r\n\tat org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1784)\r\n\tat org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)\r\n\tat org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1191)\r\n\tat org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659)\r\n\tat org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)\r\n\tat java.base/java.lang.Thread.run(Thread.java:829)\r\nCaused by: com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot deserialize value of type `java.util.LinkedHashMap<java.lang.String,java.lang.String>` from Array value (token `JsonToken.START_ARRAY`)\n at [Source: (org.springframework.util.StreamUtils$NonClosingInputStream); line: 1, column: 1]\r\n\tat com.fasterxml.jackson.databind.exc.MismatchedInputException.from(MismatchedInputException.java:59)\r\n\tat com.fasterxml.jackson.databind.DeserializationContext.reportInputMismatch(DeserializationContext.java:1741)\r\n\tat com.fasterxml.jackson.databind.DeserializationContext.handleUnexpectedToken(DeserializationContext.java:1515)\r\n\tat com.fasterxml.jackson.databind.deser.std.StdDeserializer._deserializeFromArray(StdDeserializer.java:222)\r\n\tat com.fasterxml.jackson.databind.deser.std.MapDeserializer.deserialize(MapDeserializer.java:447)\r\n\tat com.fasterxml.jackson.databind.deser.std.MapDeserializer.deserialize(MapDeserializer.java:32)\r\n\tat com.fasterxml.jackson.databind.deser.DefaultDeserializationContext.readRootValue(DefaultDeserializationContext.java:323)\r\n\tat com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:4674)\r\n\tat com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:3682)\r\n\tat org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.readJavaType(AbstractJackson2HttpMessageConverter.java:380)\r\n\t... 55 more\r\n",
    "message": "JSON parse error: Cannot deserialize value of type `java.util.LinkedHashMap<java.lang.String,java.lang.String>` from Array value (token `JsonToken.START_ARRAY`); nested exception is com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot deserialize value of type `java.util.LinkedHashMap<java.lang.String,java.lang.String>` from Array value (token `JsonToken.START_ARRAY`)\n at [Source: (org.springframework.util.StreamUtils$NonClosingInputStream); line: 1, column: 1]",
    "path": "/gdelt-mapper/info"
}

相关配置与依赖 #

POM依赖片段 #

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.7.6</version>
    <relativePath/> <!-- lookup parent from repository -->
</parent>

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-configuration-processor</artifactId>
        <optional>true</optional>
    </dependency>
    <!-- CLOUD PROPERTY MANAGEMENT -->
    <!-- Spring Configuration Client -->
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-config</artifactId>
    </dependency>
    <!-- Cloud Bus config refresh -->
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-bus-amqp</artifactId>
        <version>${spring-cloud-starter-bus-amqp.version}</version>
    </dependency>
    <!-- Starts tomcat access to actuator endpoints and connection to config server -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <!-- Starts netty -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-webflux</artifactId>
    </dependency>
</dependencies>

应用配置文件 #

server:
  port: 8314
  servlet:
    context-path: /${spring.application.name}
management:
  endpoints:
    web:
      base-path: /
      exposure:
        include: "*"
  endpoint:
    health:
      show-details: always

Jackson依赖版本 #

[INFO] |  |  +- com.fasterxml.jackson.core:jackson-annotations:jar:2.13.4:compile
[INFO] |  - com.fasterxml.jackson.core:jackson-databind:jar:2.13.4.2:compile
[INFO] |     - com.fasterxml.jackson.core:jackson-core:jar:2.13.4:compile
[INFO] |  |  +- com.fasterxml.jackson.datatype:jackson-datatype-jdk8:jar:2.13.4:compile
[INFO] |  |  +- com.fasterxml.jackson.datatype:jackson-datatype-jsr310:jar:2.13.4:compile
[INFO] |  |  - com.fasterxml.jackson.module:jackson-module-parameter-names:jar:2.13.4:compile
[INFO] |  |  +- com.fasterxml.jackson.dataformat:jackson-dataformat-cbor:jar:2.13.4:compile
[INFO] |     |        +- com.fasterxml.jackson.dataformat:jackson-dataformat-yaml:jar:2.13.4:compile

原因分析 #

1. 端点路径冲突：配置中management.endpoints.web.base-path: /将Actuator端点直接映射到应用根路径，若应用存在自定义/info接口，请求会被路由到自定义接口而非Actuator端点，而自定义接口可能期望接收Map类型请求体，导致空请求或错误输入触发解析异常。
2. Web与WebFlux共存冲突：同时引入spring-boot-starter-web和spring-boot-starter-webflux会导致Spring MVC与WebFlux的消息转换器配置冲突，Jackson反序列化规则被干扰，错误尝试将空请求解析为Map类型。
3. 路由逻辑异常：当Actuator端点与应用自定义接口路径重叠时，Spring MVC的路由优先级可能导致请求被错误分发，触发非预期的参数解析逻辑。

解决方法 #

方法一：调整Actuator基础路径 #

修改配置，给Actuator设置独立路径，避免与应用接口冲突：

management:
  endpoints:
    web:
      base-path: /actuator
      exposure:
        include: "*"

调整后访问地址为http://localhost:8314/gdelt-mapper/actuator/info

方法二：移除冲突依赖 #

若应用无需同时使用Spring MVC和WebFlux，移除其中一个依赖。例如Servlet栈应用移除WebFlux：

<!-- 移除该依赖 -->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-webflux</artifactId>
</dependency>

方法三：排查并解决接口冲突 #

检查应用中是否存在自定义@RequestMapping("/info")接口，修改其路径或调整Actuator端点路径，避免路由重叠。

方法四：自定义Jackson消息转换器 #

若必须保留Web与WebFlux共存，配置Jackson兼容空输入或不匹配类型：

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.converter.json.MappingJackson2HttpMessageConverter;
import com.fasterxml.jackson.databind.DeserializationFeature;
import com.fasterxml.jackson.databind.ObjectMapper;

@Configuration
public class JacksonConfig {
    @Bean
    public MappingJackson2HttpMessageConverter mappingJackson2HttpMessageConverter() {
        ObjectMapper objectMapper = new ObjectMapper();
        // 允许将空数组视为null对象，避免解析报错
        objectMapper.configure(DeserializationFeature.ACCEPT_EMPTY_ARRAY_AS_NULL_OBJECT, true);
        //