解决com.fasterxml.jackson.databind.JsonMappingException: No suitable constructor f

本文解决了一个在使用Jackson库将JSON字符串转换为Java Bean时遇到的问题,即由于缺少无参数构造函数导致无法实例化。

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在使用jackson 进行json字符串转java bean的时候出现如下错误,

com.fasterxml.jackson.databind.JsonMappingException: No suitable constructor found for type [simple type, class org.test.Library]: can not instantiate from JSON object (need to add/enable type information?)  at [Source: java.io.StringReader@d1831; line: 1, column: 2]
    at com.fasterxml.jackson.databind.JsonMappingException.from(JsonMappingException.java:164)
    at com.fasterxml.jackson.databind.deser.BeanDeserializerBase.deserializeFromObjectUsingNonDefault(BeanDeserializerBase.java:983)
    at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserializeFromObject(BeanDeserializer.java:276)
    at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:121)
    at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:2888)
    at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:2034)

原因java bean中没有提供无参的构造函数.

/Users/syd/Library/Java/JavaVirtualMachines/ms-17.0.14/Contents/Home/bin/java -XX:TieredStopAtLevel=1 -Dspring.profiles.active=local -Dspring.output.ansi.enabled=always -Dcom.sun.management.jmxremote -Dspring.jmx.enabled=true -Dspring.liveBeansView.mbeanDomain -Dspring.application.admin.enabled=true -Dmanagement.endpoints.jmx.exposure.include=* -javaagent:/Applications/IntelliJ IDEA.app/Contents/lib/idea_rt.jar=54141 -Dfile.encoding=UTF-8 -classpath /Users/syd/Desktop/Project/SpringCloud/黑马商城/hmall/cart-service/target/classes:/Users/syd/.m2/repository/com/alibaba/cloud/spring-cloud-starter-alibaba-nacos-config/2021.0.4.0/spring-cloud-starter-alibaba-nacos-config-2021.0.4.0.jar:/Users/syd/.m2/repository/com/alibaba/cloud/spring-cloud-alibaba-commons/2021.0.4.0/spring-cloud-alibaba-commons-2021.0.4.0.jar:/Users/syd/.m2/repository/com/alibaba/spring/spring-context-support/1.0.11/spring-context-support-1.0.11.jar:/Users/syd/.m2/repository/com/alibaba/nacos/nacos-client/2.0.4/nacos-client-2.0.4.jar:/Users/syd/.m2/repository/commons-codec/commons-codec/1.15/commons-codec-1.15.jar:/Users/syd/.m2/repository/com/fasterxml/jackson/core/jackson-core/2.13.5/jackson-core-2.13.5.jar:/Users/syd/.m2/repository/com/fasterxml/jackson/core/jackson-databind/2.13.5/jackson-databind-2.13.5.jar:/Users/syd/.m2/repository/com/fasterxml/jackson/core/jackson-annotations/2.13.5/jackson-annotations-2.13.5.jar:/Users/syd/.m2/repository/org/apache/httpcomponents/httpasyncclient/4.1.5/httpasyncclient-4.1.5.jar:/Users/syd/.m2/repository/org/apache/httpcomponents/httpcore/4.4.16/httpcore-4.4.16.jar:/Users/syd/.m2/repository/org/apache/httpcomponents/httpcore-nio/4.4.16/httpcore-nio-4.4.16.jar:/Users/syd/.m2/repository/org/apache/httpcomponents/httpclient/4.5.14/httpclient-4.5.14.jar:/Users/syd/.m2/repository/org/reflections/reflections/0.9.11/reflections-0.9.11.jar:/Users/syd/.m2/repository/com/google/guava/guava/20.0/guava-20.0.jar:/Users/syd/.m2/repository/io/prometheus/simpleclient/0.15.0/simpleclient-0.15.0.jar:/Users/syd/.m2/repository/io/prometheus/simpleclient_tracer_otel/0.15.0/simpleclient_tracer_otel-0.15.0.jar:/Users/syd/.m2/repository/io/prometheus/simpleclient_tracer_common/0.15.0/simpleclient_tracer_common-0.15.0.jar:/Users/syd/.m2/repository/io/prometheus/simpleclient_tracer_otel_agent/0.15.0/simpleclient_tracer_otel_agent-0.15.0.jar:/Users/syd/.m2/repository/org/yaml/snakeyaml/1.30/snakeyaml-1.30.jar:/Users/syd/.m2/repository/org/springframework/cloud/spring-cloud-commons/3.1.3/spring-cloud-commons-3.1.3.jar:/Users/syd/.m2/repository/org/springframework/security/spring-security-crypto/5.7.8/spring-security-crypto-5.7.8.jar:/Users/syd/.m2/repository/org/springframework/cloud/spring-cloud-context/3.1.3/spring-cloud-context-3.1.3.jar:/Users/syd/.m2/repository/org/slf4j/slf4j-api/1.7.36/slf4j-api-1.7.36.jar:/Users/syd/.m2/repository/org/springframework/cloud/spring-cloud-starter-bootstrap/3.1.3/spring-cloud-starter-bootstrap-3.1.3.jar:/Users/syd/.m2/repository/org/springframework/cloud/spring-cloud-starter/3.1.3/spring-cloud-starter-3.1.3.jar:/Users/syd/.m2/repository/org/springframework/security/spring-security-rsa/1.0.10.RELEASE/spring-security-rsa-1.0.10.RELEASE.jar:/Users/syd/.m2/repository/org/bouncycastle/bcpkix-jdk15on/1.68/bcpkix-jdk15on-1.68.jar:/Users/syd/.m2/repository/org/bouncycastle/bcprov-jdk15on/1.68/bcprov-jdk15on-1.68.jar:/Users/syd/Desktop/Project/SpringCloud/黑马商城/hmall/hm-api/target/classes:/Users/syd/.m2/repository/io/github/openfeign/feign-okhttp/11.8/feign-okhttp-11.8.jar:/Users/syd/.m2/repository/io/github/openfeign/feign-core/11.8/feign-core-11.8.jar:/Users/syd/.m2/repository/com/squareup/okhttp3/okhttp/4.9.3/okhttp-4.9.3.jar:/Users/syd/.m2/repository/com/squareup/okio/okio/2.8.0/okio-2.8.0.jar:/Users/syd/.m2/repository/org/jetbrains/kotlin/kotlin-stdlib-common/1.6.21/kotlin-stdlib-common-1.6.21.jar:/Users/syd/.m2/repository/org/jetbrains/kotlin/kotlin-stdlib/1.6.21/kotlin-stdlib-1.6.21.jar:/Users/syd/.m2/repository/org/jetbrains/annotations/13.0/annotations-13.0.jar:/Users/syd/.m2/repository/org/springframework/cloud/spring-cloud-starter-openfeign/3.1.3/spring-cloud-starter-openfeign-3.1.3.jar:/Users/syd/.m2/repository/org/springframework/cloud/spring-cloud-openfeign-core/3.1.3/spring-cloud-openfeign-core-3.1.3.jar:/Users/syd/.m2/repository/org/springframework/boot/spring-boot-starter-aop/2.7.12/spring-boot-starter-aop-2.7.12.jar:/Users/syd/.m2/repository/org/aspectj/aspectjweaver/1.9.7/aspectjweaver-1.9.7.jar:/Users/syd/.m2/repository/io/github/openfeign/form/feign-form-spring/3.8.0/feign-form-spring-3.8.0.jar:/Users/syd/.m2/repository/io/github/openfeign/form/feign-form/3.8.0/feign-form-3.8.0.jar:/Users/syd/.m2/repository/commons-fileupload/commons-fileupload/1.4/commons-fileupload-1.4.jar:/Users/syd/.m2/repository/commons-io/commons-io/2.2/commons-io-2.2.jar:/Users/syd/.m2/repository/org/springframework/spring-web/5.3.27/spring-web-5.3.27.jar:/Users/syd/.m2/repository/org/springframework/spring-beans/5.3.27/spring-beans-5.3.27.jar:/Users/syd/.m2/repository/io/github/openfeign/feign-slf4j/11.8/feign-slf4j-11.8.jar:/Users/syd/.m2/repository/com/alibaba/cloud/spring-cloud-starter-alibaba-nacos-discovery/2021.0.4.0/spring-cloud-starter-alibaba-nacos-discovery-2021.0.4.0.jar:/Users/syd/.m2/repository/org/springframework/cloud/spring-cloud-starter-loadbalancer/3.1.3/spring-cloud-starter-loadbalancer-3.1.3.jar:/Users/syd/.m2/repository/org/springframew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:/Users/syd/.m2/repository/org/springframework/boot/spring-boot-starter-tomcat/2.7.12/spring-boot-starter-tomcat-2.7.12.jar:/Users/syd/.m2/repository/org/apache/tomcat/embed/tomcat-embed-core/9.0.75/tomcat-embed-core-9.0.75.jar:/Users/syd/.m2/repository/org/apache/tomcat/embed/tomcat-embed-el/9.0.75/tomcat-embed-el-9.0.75.jar:/Users/syd/.m2/repository/org/apache/tomcat/embed/tomcat-embed-websocket/9.0.75/tomcat-embed-websocket-9.0.75.jar:/Users/syd/.m2/repository/org/springframework/spring-webmvc/5.3.27/spring-webmvc-5.3.27.jar:/Users/syd/.m2/repository/org/springframework/spring-aop/5.3.27/spring-aop-5.3.27.jar:/Users/syd/.m2/repository/org/springframework/spring-context/5.3.27/spring-context-5.3.27.jar:/Users/syd/.m2/repository/org/springframework/spring-expression/5.3.27/spring-expression-5.3.27.jar:/Users/syd/.m2/repository/mysql/mysql-connector-java/8.0.23/mysql-connector-java-8.0.23.jar:/Users/syd/.m2/repository/com/google/protobuf/protobuf-java/3.11.4/protobuf-java-3.11.4.jar:/Users/syd/.m2/repository/com/baomidou/mybatis-plus-boot-starter/3.4.3/mybatis-plus-boot-starter-3.4.3.jar:/Users/syd/.m2/repository/com/baomidou/mybatis-plus/3.4.3/mybatis-plus-3.4.3.jar:/Users/syd/.m2/repository/com/baomidou/mybatis-plus-extension/3.4.3/mybatis-plus-extension-3.4.3.jar:/Users/syd/.m2/repository/com/baomidou/mybatis-plus-core/3.4.3/mybatis-plus-core-3.4.3.jar:/Users/syd/.m2/repository/com/baomidou/mybatis-plus-annotation/3.4.3/mybatis-plus-annotation-3.4.3.jar:/Users/syd/.m2/repository/com/github/jsqlparser/jsqlparser/4.0/jsqlparser-4.0.jar:/Users/syd/.m2/repository/org/mybatis/mybatis/3.5.7/mybatis-3.5.7.jar:/Users/syd/.m2/repository/org/mybatis/mybatis-spring/2.0.6/mybatis-spring-2.0.6.jar:/Users/syd/.m2/repository/org/springframework/boot/spring-boot-starter-jdbc/2.7.12/spring-boot-starter-jdbc-2.7.12.jar:/Users/syd/.m2/repository/com/zaxxer/HikariCP/4.0.3/HikariCP-4.0.3.jar:/Users/syd/.m2/repository/org/springframework/spring-jdbc/5.3.27/spring-jdbc-5.3.27.jar:/Users/syd/.m2/repository/org/springframework/boot/spring-boot-starter-test/2.7.12/spring-boot-starter-test-2.7.12.jar:/Users/syd/.m2/repository/org/springframework/boot/spring-boot-test/2.7.12/spring-boot-test-2.7.12.jar:/Users/syd/.m2/repository/org/springframework/boot/spring-boot-test-autoconfigure/2.7.12/spring-boot-test-autoconfigure-2.7.12.jar:/Users/syd/.m2/repository/com/jayway/jsonpath/json-path/2.7.0/json-path-2.7.0.jar:/Users/syd/.m2/repository/net/minidev/json-smart/2.4.11/json-smart-2.4.11.jar:/Users/syd/.m2/repository/net/minidev/accessors-smart/2.4.11/accessors-smart-2.4.11.jar:/Users/syd/.m2/repository/org/ow2/asm/asm/9.3/asm-9.3.jar:/Users/syd/.m2/repository/jakarta/xml/bind/jakarta.xml.bind-api/2.3.3/jakarta.xml.bind-api-2.3.3.jar:/Users/syd/.m2/repository/jakarta/activation/jakarta.activation-api/1.2.2/jakarta.activation-api-1.2.2.jar:/Users/syd/.m2/repository/org/assertj/assertj-core/3.22.0/assertj-core-3.22.0.jar:/Users/syd/.m2/repository/org/hamcrest/hamcrest/2.2/hamcrest-2.2.jar:/Users/syd/.m2/repository/org/junit/jupiter/junit-jupiter/5.8.2/junit-jupiter-5.8.2.jar:/Users/syd/.m2/repository/org/junit/jupiter/junit-jupiter-api/5.8.2/junit-jupiter-api-5.8.2.jar:/Users/syd/.m2/repository/org/opentest4j/opentest4j/1.2.0/opentest4j-1.2.0.jar:/Users/syd/.m2/repository/org/junit/platform/junit-platform-commons/1.8.2/junit-platform-commons-1.8.2.jar:/Users/syd/.m2/repository/org/apiguardian/apiguardian-api/1.1.2/apiguardian-api-1.1.2.jar:/Users/syd/.m2/repository/org/junit/jupiter/junit-jupiter-params/5.8.2/junit-jupiter-params-5.8.2.jar:/Users/syd/.m2/repository/org/junit/jupiter/junit-jupiter-engine/5.8.2/junit-jupiter-engine-5.8.2.jar:/Users/syd/.m2/repository/org/junit/platform/junit-platform-engine/1.8.2/junit-platform-engine-1.8.2.jar:/Users/syd/.m2/repository/org/mockito/mockito-core/4.5.1/mockito-core-4.5.1.jar:/Users/syd/.m2/repository/net/bytebuddy/byte-buddy/1.12.23/byte-buddy-1.12.23.jar:/Users/syd/.m2/repository/net/bytebuddy/byte-buddy-agent/1.12.23/byte-buddy-agent-1.12.23.jar:/Users/syd/.m2/repository/org/objenesis/objenesis/3.2/objenesis-3.2.jar:/Users/syd/.m2/repository/org/mockito/mockito-junit-jupiter/4.5.1/mockito-junit-jupiter-4.5.1.jar:/Users/syd/.m2/repository/org/skyscreamer/jsonassert/1.5.1/jsonassert-1.5.1.jar:/Users/syd/.m2/repository/com/vaadin/external/google/android-json/0.0.20131108.vaadin1/android-json-0.0.20131108.vaadin1.jar:/Users/syd/.m2/repository/org/springframework/spring-core/5.3.27/spring-core-5.3.27.jar:/Users/syd/.m2/repository/org/springframework/spring-jcl/5.3.27/spring-jcl-5.3.27.jar:/Users/syd/.m2/repository/org/springframework/spring-test/5.3.27/spring-test-5.3.27.jar:/Users/syd/.m2/repository/org/xmlunit/xmlunit-core/2.9.1/xmlunit-core-2.9.1.jar:/Users/syd/.m2/repository/org/springframework/boot/spring-boot-starter-data-redis/2.7.12/spring-boot-starter-data-redis-2.7.12.jar:/Users/syd/.m2/repository/org/springframework/data/spring-data-redis/2.7.12/spring-data-redis-2.7.12.jar:/Users/syd/.m2/repository/org/springframework/data/spring-data-keyvalue/2.7.12/spring-data-keyvalue-2.7.12.jar:/Users/syd/.m2/repository/org/springframework/data/spring-data-commons/2.7.12/spring-data-commons-2.7.12.jar:/Users/syd/.m2/repository/org/springframework/spring-tx/5.3.27/spring-tx-5.3.27.jar:/Users/syd/.m2/repository/org/springframework/spring-oxm/5.3.27/spring-oxm-5.3.27.jar:/Users/syd/.m2/repository/io/lettuce/lettuce-core/6.1.10.RELEASE/lettuce-core-6.1.10.RELEASE.jar:/Users/syd/.m2/repository/io/netty/netty-common/4.1.92.Final/netty-common-4.1.92.Final.jar:/Users/syd/.m2/repository/io/netty/netty-handler/4.1.92.Final/netty-handler-4.1.92.Final.jar:/Users/syd/.m2/repository/io/netty/netty-resolver/4.1.92.Final/netty-resolver-4.1.92.Final.jar:/Users/syd/.m2/repository/io/netty/netty-buffer/4.1.92.Final/netty-buffer-4.1.92.Final.jar:/Users/syd/.m2/repository/io/netty/netty-transport-native-unix-common/4.1.92.Final/netty-transport-native-unix-common-4.1.92.Final.jar:/Users/syd/.m2/repository/io/netty/netty-codec/4.1.92.Final/netty-codec-4.1.92.Final.jar:/Users/syd/.m2/repository/io/netty/netty-transport/4.1.92.Final/netty-transport-4.1.92.Final.jar:/Users/syd/.m2/repository/org/projectlombok/lombok/1.18.20/lombok-1.18.20.jar com.hmall.cart.CartApplication . ____ _ __ _ _ /\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \ ( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \ \\/ ___)| |_)| | | | | || (_| | ) ) ) ) ' |____| .__|_| |_|_| |_\__, | / / / / =========|_|==============|___/=/_/_/_/ :: Spring Boot :: (v2.7.12) 2025-07-23 00:46:10.823 INFO 94996 --- [ main] com.alibaba.nacos.common.remote.client : [RpcClientFactory] create a new rpc client of 02474581-6045-4ae2-bf28-5abda8e7177f_config-0 2025-07-23 00:46:10.851 INFO 94996 --- [ main] org.reflections.Reflections : Reflections took 13 ms to scan 1 urls, producing 3 keys and 6 values 2025-07-23 00:46:10.863 INFO 94996 --- [ main] org.reflections.Reflections : Reflections took 6 ms to scan 1 urls, producing 4 keys and 9 values 2025-07-23 00:46:10.868 INFO 94996 --- [ main] org.reflections.Reflections : Reflections took 4 ms to scan 1 urls, producing 3 keys and 10 values 2025-07-23 00:46:10.869 WARN 94996 --- [ main] org.reflections.Reflections : given scan urls are empty. set urls in the configuration 2025-07-23 00:46:10.873 INFO 94996 --- [ main] org.reflections.Reflections : Reflections took 4 ms to scan 1 urls, producing 1 keys and 5 values 2025-07-23 00:46:10.882 INFO 94996 --- [ main] org.reflections.Reflections : Reflections took 8 ms to scan 1 urls, producing 1 keys and 7 values 2025-07-23 00:46:10.887 INFO 94996 --- [ main] org.reflections.Reflections : Reflections took 4 ms to scan 1 urls, producing 2 keys and 8 values 2025-07-23 00:46:10.888 WARN 94996 --- [ main] org.reflections.Reflections : given scan urls are empty. set urls in the configuration 2025-07-23 00:46:10.888 INFO 94996 --- [ main] com.alibaba.nacos.common.remote.client : [02474581-6045-4ae2-bf28-5abda8e7177f_config-0] RpcClient init label, labels = {module=config, Vipserver-Tag=null, source=sdk, Amory-Tag=null, Location-Tag=null, taskId=0, AppName=unknown} 2025-07-23 00:46:10.888 INFO 94996 --- [ main] com.alibaba.nacos.common.remote.client : [02474581-6045-4ae2-bf28-5abda8e7177f_config-0] Register server push request handler:com.alibaba.nacos.client.config.impl.ClientWorker$ConfigRpcTransportClient$$Lambda$469/0x000000800139e810 2025-07-23 00:46:10.888 INFO 94996 --- [ main] com.alibaba.nacos.common.remote.client : [02474581-6045-4ae2-bf28-5abda8e7177f_config-0] Register server push request handler:com.alibaba.nacos.client.config.impl.ClientWorker$ConfigRpcTransportClient$$Lambda$470/0x000000800139ea38 2025-07-23 00:46:10.889 INFO 94996 --- [ main] com.alibaba.nacos.common.remote.client : [02474581-6045-4ae2-bf28-5abda8e7177f_config-0] Registry connection listener to current client:com.alibaba.nacos.client.config.impl.ClientWorker$ConfigRpcTransportClient$1 2025-07-23 00:46:10.889 INFO 94996 --- [ main] com.alibaba.nacos.common.remote.client : [02474581-6045-4ae2-bf28-5abda8e7177f_config-0] RpcClient init, ServerListFactory = com.alibaba.nacos.client.config.impl.ClientWorker$ConfigRpcTransportClient$2 2025-07-23 00:46:10.892 INFO 94996 --- [ main] com.alibaba.nacos.common.remote.client : [02474581-6045-4ae2-bf28-5abda8e7177f_config-0] Try to connect to server on start up, server: {serverIp = '127.0.0.1', server main port = 8848} 2025-07-23 00:46:11.264 INFO 94996 --- [ main] com.alibaba.nacos.common.remote.client : [02474581-6045-4ae2-bf28-5abda8e7177f_config-0] Success to connect to server [127.0.0.1:8848] on start up, connectionId = 1753202771127_192.168.65.1_22625 2025-07-23 00:46:11.264 INFO 94996 --- [ main] com.alibaba.nacos.common.remote.client : [02474581-6045-4ae2-bf28-5abda8e7177f_config-0] Register server push request handler:com.alibaba.nacos.common.remote.client.RpcClient$ConnectResetRequestHandler 2025-07-23 00:46:11.264 INFO 94996 --- [t.remote.worker] com.alibaba.nacos.common.remote.client : [02474581-6045-4ae2-bf28-5abda8e7177f_config-0] Notify connected event to listeners. 2025-07-23 00:46:11.265 INFO 94996 --- [ main] com.alibaba.nacos.common.remote.client : [02474581-6045-4ae2-bf28-5abda8e7177f_config-0] Register server push request handler:com.alibaba.nacos.common.remote.client.RpcClient$$Lambda$481/0x00000080015077c0 2025-07-23 00:46:11.296 WARN 94996 --- [ main] c.a.c.n.c.NacosPropertySourceBuilder : Ignore the empty nacos configuration and get it based on dataId[cart-service] & group[DEFAULT_GROUP] 2025-07-23 00:46:11.301 WARN 94996 --- [ main] c.a.c.n.c.NacosPropertySourceBuilder : Ignore the empty nacos configuration and get it based on dataId[cart-service.yaml] & group[DEFAULT_GROUP] 2025-07-23 00:46:11.304 WARN 94996 --- [ main] c.a.c.n.c.NacosPropertySourceBuilder : Ignore the empty nacos configuration and get it based on dataId[cart-service-local.yaml] & group[DEFAULT_GROUP] 2025-07-23 00:46:11.305 INFO 94996 --- [ main] b.c.PropertySourceBootstrapConfiguration : Located property source: [BootstrapPropertySource {name='bootstrapProperties-cart-service-local.yaml,DEFAULT_GROUP'}, BootstrapPropertySource {name='bootstrapProperties-cart-service.yaml,DEFAULT_GROUP'}, BootstrapPropertySource {name='bootstrapProperties-cart-service,DEFAULT_GROUP'}, BootstrapPropertySource {name='bootstrapProperties-knife4j,DEFAULT_GROUP'}, BootstrapPropertySource {name='bootstrapProperties-JDBC,DEFAULT_GROUP'}] 2025-07-23 00:46:11.307 INFO 94996 --- [ main] com.hmall.cart.CartApplication : The following 1 profile is active: "local" 2025-07-23 00:46:11.594 INFO 94996 --- [ main] .s.d.r.c.RepositoryConfigurationDelegate : Multiple Spring Data modules found, entering strict repository configuration mode 2025-07-23 00:46:11.596 INFO 94996 --- [ main] .s.d.r.c.RepositoryConfigurationDelegate : Bootstrapping Spring Data Redis repositories in DEFAULT mode. 2025-07-23 00:46:11.607 INFO 94996 --- [ main] .s.d.r.c.RepositoryConfigurationDelegate : Finished Spring Data repository scanning in 4 ms. Found 0 Redis repository interfaces. 2025-07-23 00:46:11.708 INFO 94996 --- [ main] o.s.cloud.context.scope.GenericScope : BeanFactory id=639213e3-93fa-3eac-8cc8-3f4e5c6acd59 2025-07-23 00:46:11.910 INFO 94996 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat initialized with port(s): 8082 (http) 2025-07-23 00:46:11.915 INFO 94996 --- [ main] o.apache.catalina.core.StandardService : Starting service [Tomcat] 2025-07-23 00:46:11.915 INFO 94996 --- [ main] org.apache.catalina.core.StandardEngine : Starting Servlet engine: [Apache Tomcat/9.0.75] 2025-07-23 00:46:11.971 INFO 94996 --- [ main] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring embedded WebApplicationContext 2025-07-23 00:46:11.971 INFO 94996 --- [ main] w.s.c.ServletWebServerApplicationContext : Root WebApplicationContext: initialization completed in 654 ms 2025-07-23 00:46:12.049 INFO 94996 --- [ main] o.s.c.openfeign.FeignClientFactoryBean : For 'item-service' URL not provided. Will try picking an instance via load-balancing. 2025-07-23 00:46:12.183 WARN 94996 --- [ main] ConfigServletWebServerApplicationContext : Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'cartController' defined in file [/Users/syd/Desktop/Project/SpringCloud/黑马商城/hmall/cart-service/target/classes/com/hmall/cart/controller/CartController.class]: Unsatisfied dependency expressed through constructor parameter 0; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'cartServiceImpl': Unsatisfied dependency expressed through field 'baseMapper'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'cartMapper' defined in file [/Users/syd/Desktop/Project/SpringCloud/黑马商城/hmall/cart-service/target/classes/com/hmall/cart/mapper/CartMapper.class]: Unsatisfied dependency expressed through bean property 'sqlSessionFactory'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'sqlSessionFactory' defined in class path resource [com/baomidou/mybatisplus/autoconfigure/MybatisPlusAutoConfiguration.class]: Unsatisfied dependency expressed through method 'sqlSessionFactory' parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource' defined in class path resource [org/springframework/boot/autoconfigure/jdbc/DataSourceConfiguration$Hikari.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.zaxxer.hikari.HikariDataSource]: Factory method 'dataSource' threw exception; nested exception is org.springframework.boot.autoconfigure.jdbc.DataSourceProperties$DataSourceBeanCreationException: Failed to determine a suitable driver class 2025-07-23 00:46:12.185 INFO 94996 --- [ main] o.apache.catalina.core.StandardService : Stopping service [Tomcat] 2025-07-23 00:46:12.194 INFO 94996 --- [ main] ConditionEvaluationReportLoggingListener : Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled. 2025-07-23 00:46:12.202 ERROR 94996 --- [ main] o.s.b.d.LoggingFailureAnalysisReporter : *************************** APPLICATION FAILED TO START *************************** Description: Failed to configure a DataSource: 'url' attribute is not specified and no embedded datasource could be configured. Reason: Failed to determine a suitable driver class Action: Consider the following: If you want an embedded database (H2, HSQL or Derby), please put it on the classpath. If you have database settings to be loaded from a particular profile you may need to activate it (the profiles local are currently active). 2025-07-23 00:46:12.203 WARN 94996 --- [ Thread-7] c.a.nacos.common.notify.NotifyCenter : [NotifyCenter] Start destroying Publisher 2025-07-23 00:46:12.203 WARN 94996 --- [ Thread-7] c.a.nacos.common.notify.NotifyCenter : [NotifyCenter] Destruction of the end 2025-07-23 00:46:12.203 WARN 94996 --- [ Thread-1] c.a.n.common.http.HttpClientBeanHolder : [HttpClientBeanHolder] Start destroying common HttpClient 进程已结束,退出代码为 1
最新发布
07-24
<think>首先,用户的问题是:“我想解决Jackson反序列化过程中出现的JsonMappingException异常 请问Jackson JsonMappingException Unexpected end-of-input in VALUE_STRING 解决方法”。用户提到了具体的异常:`JsonMappingException: Unexpected end-of-input in VALUE_STRING`。 根据系统级指令: - 所有行内数学表达式必须使用 `$...$` 格式。 - 独立公式必须使用 `$$...$$` 格式并单独成段。 - LaTeX语法正确。 - 使用中文回答。 - 生成相关问题。 - 回答中引用的段落末尾自然地添加引用标识,例如: [^1]。 用户可见层要求: - 回答结构清晰,帮助用户逐步解决问题,尽量保证回答真实可靠。 - 参考站内引用:用户提供了几个引用,我需要参考这些来构建回答。 提供的引用: - [^1]: 描述了错误是JSON解析错误,期望的字符串值没有正常结束。 - [^2]: 异常细节,包括位置信息。 - [^3]: 提到在Postman中遇到类似错误。 - [^4]: 提供了一个拦截器代码来打印请求体,帮助诊断。 - [^5]: 关于Lettuce连接和Spring Boot依赖的代码片段,但似乎不直接相关。 用户的上一次问题或上下文:用户说“上述引用仅供参考,并不是用户真正的需求”,所以我应该专注于用户当前的问题,即解决Jackson反序列化中的`JsonMappingException`。 关键点: - 异常:`JsonMappingException: Unexpected end-of-input in VALUE_STRING` - 原因:JSON字符串在解析过程中提前结束,导致无法正确读取字符串值。 - 常见场景:JSON数据格式错误,比如字符串缺少闭合引号、数据不完整等。 我需要构建一个结构清晰的回答: 1. **解释问题**:简要说明异常的含义和常见原因。 2. **诊断步骤**:提供如何诊断问题的方法,比如检查JSON数据。 3. **解决方法**:列出可能的解决方案。 4. **生成相关问题**:在回答末尾添加相关问题。 参考提供的引用: - 从[^4]中,用户提供了拦截器代码来打印请求体,这可以用于诊断。我可以建议类似的方法。 - [^1]和[^2]解释了错误原因。 - [^3]提到了Postman,所以可能涉及测试工具。 回答结构: - **引言**:确认问题并解释异常。 - **步骤1:理解异常**:详细说明`Unexpected end-of-input in VALUE_STRING`的含义。 - **步骤2:诊断问题**:建议如何检查JSON数据。 - 使用拦截器打印请求体(参考[^4])。 - 检查JSON是否完整。 - **步骤3:常见原因和解决方案**: - JSON字符串缺少闭合引号。 - 数据不完整,比如网络传输中断。 - 编码问题。 - 使用工具验证JSON,如Postman或在线验证器。 - **步骤4:代码示例**:如果需要,提供代码片段。 - **结论**:总结关键点。 - **相关问题**:生成3个相关问题。 确保使用中文回答。 生成相关问题: - 基于主题,如Jackson的其他异常、JSON处理最佳实践等。 最终回答大纲: 1. 解释异常。 2. 诊断方法。 3. 解决方案。 4. 相关问题。</think>### Jackson `JsonMappingException: Unexpected end-of-input in VALUE_STRING` 解决方法 您好!您遇到的 `JsonMappingException: Unexpected end-of-input in VALUE_STRING` 异常是 Jackson 库在反序列化 JSON 数据时常见的错误。它表示解析器在读取字符串值(如 `"key": "value"`)时,输入数据提前结束,导致无法完成解析。这通常是由于 JSON 数据格式错误或不完整引起的。下面我将一步步帮您诊断和解决这个问题。回答基于 Jackson 的常见处理实践和参考信息[^1][^2][^3]。 #### 步骤 1: 理解异常原因 - **异常含义**:`Unexpected end-of-input in VALUE_STRING` 意味着 Jackson 在解析字符串值时,发现 JSON 输入流提前终止。例如: - 字符串缺少闭合引号:如 `{"name": "Alice`(缺少结尾的 `"`)。 - 数据不完整:网络传输中断或文件损坏导致 JSON 被截断。 - 特殊字符未转义:如字符串中包含未转义的引号或换行符。 - **常见场景**: - 在 HTTP 请求中(如 Postman 测试),请求体不完整或格式错误[^3]。 - 反序列化时使用 `ObjectMapper.readValue()` 方法处理无效数据。 - 参考引用中,类似错误常出现在 JSON 解析阶段,Jackson 期望读取完整的字符串值但输入提前结束[^1][^2]。 #### 步骤 2: 诊断问题 在修复前,先确认 JSON 数据的完整性。以下是推荐诊断方法: - **打印请求体**:使用拦截器捕获 HTTP 请求的原始数据(参考引用[^4])。以下是一个 Spring Boot 拦截器示例,用于输出请求体: ```java import org.springframework.web.servlet.HandlerInterceptor; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.apache.commons.io.IOUtils; import java.nio.charset.StandardCharsets; public class RequestLoggingInterceptor implements HandlerInterceptor { @Override public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception { // 读取并打印请求体 String body = IOUtils.toString(request.getInputStream(), StandardCharsets.UTF_8); System.out.println("Request Body: " + body); // 输出到日志,便于检查 return true; // 继续处理请求 } } ``` - **使用方法**:注册此拦截器到 Spring 配置中。运行后,检查控制台输出,确认 JSON 是否完整(例如,检查引号是否配对)。 - **验证 JSON 格式**: - 使用在线工具(如 [JSONLint](https://jsonlint.com/))粘贴您的 JSON 数据,自动检测语法错误。 - 在 Postman 中测试时,确保请求体是有效的 JSON(选择 `raw` 格式并设置 `Content-Type: application/json`)[^3]。 - **检查数据源**: - 如果是文件或数据库读取,确保数据未损坏。 - 网络传输中,添加超时和重试机制,避免数据丢失。 #### 步骤 3: 常见解决方案 针对诊断结果,选择以下方法修复: 1. **修复 JSON 格式**: - 确保所有字符串值有闭合引号,例如:`{"name": "Alice"}` 而不是 `{"name": "Alice`。 - 转义特殊字符:在字符串中使用 `\"` 表示引号,如 `{"message": "He said, \"Hello\""}`。 - 使用 Jackson 的 `JsonParser.Feature` 启用宽松解析(不推荐,仅临时用): ```java ObjectMapper mapper = new ObjectMapper(); mapper.configure(JsonParser.Feature.ALLOW_UNQUOTED_FIELD_NAMES, true); // 允许未加引号的字段名 mapper.configure(JsonParser.Feature.IGNORE_UNDEFINED, true); // 忽略未定义属性 YourClass obj = mapper.readValue(jsonString, YourClass.class); ``` - **注意**:宽松模式可能掩盖其他错误,优先手动修复 JSON。 2. **处理数据完整性**: - 如果数据来自网络,检查客户端和服务端代码: - 客户端:确保发送完整 JSON,例如在 JavaScript 中使用 `JSON.stringify()`。 - 服务端:添加输入验证,如 Spring Boot 的 `@Valid` 注解。 - 使用 try-catch 捕获异常并提供友好错误: ```java try { YourClass obj = objectMapper.readValue(jsonString, YourClass.class); } catch (JsonMappingException e) { System.err.println("JSON 解析错误: " + e.getMessage()); // 提示用户检查数据格式 } ``` 3. **编码和依赖问题**: - **统一编码**:确保所有系统使用 UTF-8(参考引用[^4]),在读取流时指定编码: ```java String body = new String(bytes, StandardCharsets.UTF_8); // 明确使用 UTF-8 ``` - **检查 Jackson 版本**:过时版本可能有 bug。更新依赖(参考您的 pom.xml): ```xml <dependency> <groupId>com.fasterxml.jackson.core</groupId> <artifactId>jackson-databind</artifactId> <version>2.17.0</version> <!-- 使用最新稳定版 --> </dependency> ``` - 如果涉及 Redis 等中间件(如引用[^5]),确保数据序列化一致。 4. **高级调试**: - 启用 Jackson 的详细日志:在 `application.properties` 中添加: ``` logging.level.com.fasterxml.jackson=DEBUG ``` - 使用单元测试:创建测试用例模拟无效 JSON,验证异常处理。 #### 步骤 4: 预防措施 - **最佳实践**: - 始终在接收端验证 JSON 格式。 - 使用库如 `org.json` 或 Jackson 的 `JsonNode` 预解析 JSON: ```java JsonNode node = objectMapper.readTree(jsonString); // 先解析为树结构,检查节点 ``` - 在 Postman 或前端添加数据校验,减少无效请求。 - **总结**:此异常通常源于数据问题而非代码 bug。通过诊断请求体并修复 JSON 完整性,即可解决[^1][^4]。如果问题持续,提供更多上下文(如 JSON 示例)以便进一步分析。
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