Jackson NoSuchMethodError requiresPropertyOrdering maven with google app engine project at runtime答案

【问题标题】：Jackson NoSuchMethodError requiresPropertyOrdering maven with google app engine project at runtimeJackson NoSuchMethodError requiresPropertyOrdering maven with google app engine project at runtime
【发布时间】：2014-08-18 17:34:44
【问题描述】：

我正在尝试运行一个应用程序引擎 maven 项目，但似乎发现自己陷入了 JAR 地狱。该项目过去已在不使用 maven 的情况下构建和运行，但我已经受够了 Eclipse 的废话，并且出于所有通常的原因正在尝试对项目进行 mavenize。

目前一切都在编译并且测试正在通过（mvn clean install 来自myproject-war 目录shown here）。我还可以从我的myproject-ear 目录启动mvn appengine:devserver 并让服务器运行。然而，导航到我的一个 servlet，我得到了如下所示的 noSuchMethodError 跟踪。（为了便于阅读，所有代码都在底部）。

这看起来类似于 other posts，其中杰克逊版本不同步。但是，我的杰克逊版本似乎还可以，正如我在底部的pom.xml 中所见。看起来那个方法didn't appear until Jackson 3.0，由于mvn dependency:tree -Dverbose | ack jackson 的输出以及我依赖2.4.1 的事实，这似乎还可以。

我能想到的最可能的罪魁祸首是我正在使用的谷歌图书馆，因为我正在关注似乎依赖它的example here。但是，我不确定如何测试该假设或让谷歌库在没有依赖的情况下工作。也许是<exlcudes> 标签，但我不确定如何应用它。

有没有人有任何建议或我缺少的东西？如何获得要在运行时使用的正确版本的类？还是我错过了什么，解决方案完全不同？

编辑：请注意，根据评论/答案的建议，我确保我负责的所有库都使用相同版本的 fastxml/Jackson，而不是旧的 codehaus 打包。我同意似乎在某处仍然存在导致问题的旧依赖项，但这正是我正在努力纠正的问题。

编辑 2：当我清理了整个项目和依赖结构时，我最终得到了这个工作，尽管我无法提供确切的解决方法。我认为问题是由于这种依赖关系：

<dependency>
  <groupId>com.fasterxml.jackson.jaxrs</groupId>
  <artifactId>jackson-jaxrs-json-provider</artifactId>
  <version>2.4.1</version>
</dependency>

org.jboss.resteasy:resteasy-jackson2-provider:3.0.6.Final 上的 has a dependency，它本身 depends on com.fasterxml.jackson.core:jackson-databind:2.2.1，它没有缺少的方法，正如我在原始帖子中指出的那样。

mvn dependency:tree -Dverbose | ack jackson:

[INFO] +- com.fasterxml.jackson.jaxrs:jackson-jaxrs-json-provider:jar:2.4.1:compile
[INFO] |  +- com.fasterxml.jackson.jaxrs:jackson-jaxrs-base:jar:2.4.1:compile
[INFO] |  |  +- (com.fasterxml.jackson.core:jackson-core:jar:2.4.1:compile - omitted for duplicate)
[INFO] |  |  \- (com.fasterxml.jackson.core:jackson-databind:jar:2.4.1:compile - omitted for duplicate)
[INFO] |  +- (com.fasterxml.jackson.core:jackson-core:jar:2.4.1:compile - omitted for duplicate)
[INFO] |  +- (com.fasterxml.jackson.core:jackson-databind:jar:2.4.1:compile - omitted for duplicate)
[INFO] |  \- com.fasterxml.jackson.module:jackson-module-jaxb-annotations:jar:2.4.1:compile
[INFO] |     +- (com.fasterxml.jackson.core:jackson-core:jar:2.4.1:compile - omitted for duplicate)
[INFO] |     \- (com.fasterxml.jackson.core:jackson-databind:jar:2.4.1:compile - omitted for duplicate)
[INFO] +- com.fasterxml.jackson.core:jackson-core:jar:2.4.1:compile
[INFO] +- com.fasterxml.jackson.core:jackson-databind:jar:2.4.1:compile
[INFO] |  +- com.fasterxml.jackson.core:jackson-annotations:jar:2.4.0:compile
[INFO] |  \- (com.fasterxml.jackson.core:jackson-core:jar:2.4.1:compile - omitted for duplicate)
[INFO] |  +- com.google.http-client:google-http-client-jackson2:jar:1.19.0:compile
[INFO] |  |  \- (com.fasterxml.jackson.core:jackson-core:jar:2.1.3:compile - omitted for conflict with 2.4.1)
[INFO] +- org.codehaus.jackson:jackson-mapper-asl:jar:1.9.13:test
[INFO] |  \- org.codehaus.jackson:jackson-core-asl:jar:1.9.13:test

异常跟踪：

java.lang.NoSuchMethodError: com.fasterxml.jackson.core.JsonFactory.requiresPropertyOrdering()Z
    at com.fasterxml.jackson.databind.ObjectMapper.<init>(ObjectMapper.java:458)
    at com.fasterxml.jackson.databind.ObjectMapper.<init>(ObjectMapper.java:379)
    at com.fasterxml.jackson.jaxrs.json.JsonMapperConfigurator.getDefaultMapper(JsonMapperConfigurator.java:44)
    at com.fasterxml.jackson.jaxrs.base.ProviderBase.locateMapper(ProviderBase.java:856)
    at com.fasterxml.jackson.jaxrs.base.ProviderBase.writeTo(ProviderBase.java:588)
    at org.jboss.resteasy.core.interception.AbstractWriterInterceptorContext.writeTo(AbstractWriterInterceptorContext.java:129)
    at org.jboss.resteasy.core.interception.ServerWriterInterceptorContext.writeTo(ServerWriterInterceptorContext.java:62)
    at org.jboss.resteasy.core.interception.AbstractWriterInterceptorContext.proceed(AbstractWriterInterceptorContext.java:118)
    at org.jboss.resteasy.plugins.interceptors.encoding.GZIPEncodingInterceptor.aroundWriteTo(GZIPEncodingInterceptor.java:100)
    at org.jboss.resteasy.core.interception.AbstractWriterInterceptorContext.proceed(AbstractWriterInterceptorContext.java:122)
    at org.jboss.resteasy.core.ServerResponseWriter.writeNomapResponse(ServerResponseWriter.java:99)
    at org.jboss.resteasy.core.SynchronousDispatcher.writeResponse(SynchronousDispatcher.java:427)
    at org.jboss.resteasy.core.SynchronousDispatcher.invoke(SynchronousDispatcher.java:376)
    at org.jboss.resteasy.core.SynchronousDispatcher.invoke(SynchronousDispatcher.java:179)
    at org.jboss.resteasy.plugins.server.servlet.ServletContainerDispatcher.service(ServletContainerDispatcher.java:220)
    at org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher.service(HttpServletDispatcher.java:56)
    at org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher.service(HttpServletDispatcher.java:51)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
    at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:511)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1166)
    at com.google.appengine.api.socket.dev.DevSocketFilter.doFilter(DevSocketFilter.java:74)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at com.google.appengine.tools.development.ResponseRewriterFilter.doFilter(ResponseRewriterFilter.java:127)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at com.google.appengine.tools.development.HeaderVerificationFilter.doFilter(HeaderVerificationFilter.java:34)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at com.google.appengine.api.blobstore.dev.ServeBlobFilter.doFilter(ServeBlobFilter.java:63)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter(TransactionCleanupFilter.java:43)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at com.google.appengine.tools.development.StaticFileFilter.doFilter(StaticFileFilter.java:125)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at com.google.appengine.tools.development.DevAppServerModulesFilter.doDirectRequest(DevAppServerModulesFilter.java:366)
    at com.google.appengine.tools.development.DevAppServerModulesFilter.doDirectModuleRequest(DevAppServerModulesFilter.java:349)
    at com.google.appengine.tools.development.DevAppServerModulesFilter.doFilter(DevAppServerModulesFilter.java:116)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:388)
    at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
    at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
    at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765)
    at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:418)
    at com.google.appengine.tools.development.DevAppEngineWebAppContext.handle(DevAppEngineWebAppContext.java:98)
    at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
    at com.google.appengine.tools.development.JettyContainerService$ApiProxyHandler.handle(JettyContainerService.java:491)
    at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
    at org.mortbay.jetty.Server.handle(Server.java:326)
    at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
    at org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:923)
    at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:547)
    at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:212)
    at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
    at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:409)
    at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:582)

我的pom.xml：

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">

<modelVersion>4.0.0</modelVersion>
<packaging>war</packaging>
<version>1.0-SNAPSHOT</version>
<groupId>org.mygroupid</groupId>
<artifactId>myproject-server-war</artifactId>

<parent>
    <groupId>org.mygroupid</groupId>
    <artifactId>myproject-server</artifactId>
    <version>1.0-SNAPSHOT</version>
</parent>

<properties>
    <appengine.app.version>1-war</appengine.app.version>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>

<dependencies>
    <!-- Compile/runtime dependencies -->
    <dependency>
        <groupId>com.google.appengine</groupId>
        <artifactId>appengine-api-1.0-sdk</artifactId>
        <version>${appengine.target.version}</version>
    </dependency>
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>servlet-api</artifactId>
        <version>2.5</version>
        <scope>provided</scope>
    </dependency>
    <dependency>
        <groupId>jstl</groupId>
        <artifactId>jstl</artifactId>
        <version>1.2</version>
    </dependency>

    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>5.1.31</version>
    </dependency>

    <dependency>
      <groupId>com.fasterxml.jackson.jaxrs</groupId>
      <artifactId>jackson-jaxrs-json-provider</artifactId>
      <version>2.4.1</version>
    </dependency>

    <dependency>
      <groupId>com.fasterxml.jackson.core</groupId>
      <artifactId>jackson-core</artifactId>
      <version>2.4.1</version>
    </dependency>

    <dependency>
      <groupId>com.fasterxml.jackson.core</groupId>
      <artifactId>jackson-databind</artifactId>
      <version>2.4.1</version>
    </dependency>

    <dependency>
      <groupId>joda-time</groupId>
      <artifactId>joda-time</artifactId>
      <version>2.3</version>
    </dependency>


    <dependency>
        <groupId>org.hibernate</groupId>
        <artifactId>hibernate-core</artifactId>
        <version>4.2.8.Final</version>
    </dependency>

    <dependency>
      <groupId>org.hibernate.common</groupId>
      <artifactId>hibernate-commons-annotations</artifactId>
      <version>4.0.4.Final</version>
    </dependency>

    <dependency>
      <groupId>org.jboss.resteasy</groupId>
      <artifactId>resteasy-jaxrs</artifactId>
      <version>3.0.8.Final</version>
    </dependency>

    <dependency>
      <groupId>com.google.api-client</groupId>
      <artifactId>google-api-client</artifactId>
      <version>1.19.0</version>
    </dependency>

    <dependency>
      <groupId>com.google.api-client</groupId>
      <artifactId>google-api-client-gson</artifactId>
      <version>1.19.0</version>
    </dependency>



    <!-- Our custom common jar. -->
    <dependency>
        <groupId>groupid</groupId>
        <artifactId>myproject-common</artifactId>
        <version>0.1-SNAPSHOT</version>
    </dependency>

    <!-- Test Dependencies -->
    <dependency>
        <groupId>com.google.appengine</groupId>
        <artifactId>appengine-testing</artifactId>
        <version>${appengine.target.version}</version>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>com.google.appengine</groupId>
        <artifactId>appengine-api-stubs</artifactId>
        <version>${appengine.target.version}</version>
        <scope>test</scope>
    </dependency>

    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.10</version>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>org.mockito</groupId>
        <artifactId>mockito-all</artifactId>
        <version>1.9.0</version>
        <scope>test</scope>
    </dependency>

    <dependency>
        <groupId>groupdId</groupId>
        <artifactId>myproject-common</artifactId>
        <version>0.1-SNAPSHOT</version>
        <scope>test</scope>
    </dependency>

    <dependency>
      <groupId>org.codehaus.jackson</groupId>
      <artifactId>jackson-mapper-asl</artifactId>
      <version>1.9.13</version>
      <scope>test</scope>
    </dependency>


    <dependency>
      <groupId>org.easytesting</groupId>
      <artifactId>fest-assert-core</artifactId>
      <version>2.0M10</version>
      <scope>test</scope>
    </dependency>


</dependencies>

<build>
    <outputDirectory>target/${project.artifactId}-${project.version}/WEB-INF/classes</outputDirectory> 

    <plugins>

      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-compiler-plugin</artifactId>
        <version>3.1</version>
        <configuration>
            <source>1.7</source>
            <target>1.7</target>
        </configuration>
    </plugin>

        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-war-plugin</artifactId>
            <version>2.3</version>
            <configuration>
                <archiveClasses>true</archiveClasses>
                <webResources>
                    <!-- in order to interpolate version from pom into appengine-web.xml -->
                    <resource>
                        <directory>${basedir}/src/main/webapp/WEB-INF</directory>
                        <filtering>true</filtering>
                        <targetPath>WEB-INF</targetPath>
                    </resource>
                </webResources>
            </configuration>
        </plugin>
    </plugins>
</build>

【问题讨论】：

我使用 Jackson 2.4.1 和 GAE 1.9.7 没有问题。您在类路径中包含一些您无法将其视为临时依赖项的内容。
如何追踪这样的问题？另外，为什么要投反对票？如果我知道怎么做，很乐意提出更好的问题。
删除所有内容并一次添加一个内容，直到出现错误，然后您就发现了问题，就像您调试其他任何内容一样。我的项目一切正常，您的问题非常局限在您的项目中。
如果我在编译时看到错误，一次删除一个东西会很容易。由于我是在运行时获得它，因此我必须包含要构建的项目，因此很难一次删除一个并隔离问题。如果有办法做到这一点，我很抱歉不知道。
您将旧版本的依赖项与最新版本混合在一起，这将永远不会结束。更新到所有依赖项的最新版本。

标签： java google-app-engine maven

【解决方案1】：

这就是 GAE 1.9.7 对我有用的东西

属性

<properties>
    <appengine.target.version>1.9.7</appengine.target.version>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <resteasy.version>3.0.8.Final</resteasy.version>
    <jackson.version>2.4.1</jackson.version>
    <slf4j.version>1.7.7</slf4j.version>
    <reflections.version>0.9.9-RC2</reflections.version>
</properties>

依赖管理

<dependencyManagement>

    <dependencies>

        <!-- Third Party Dependencies -->

        <dependency>
            <groupId>com.google.code.findbugs</groupId>
            <artifactId>findbugs</artifactId>
            <version>3.0.0</version>
        </dependency>

        <dependency>
            <groupId>org.reflections</groupId>
            <artifactId>reflections</artifactId>
            <version>${reflections.version}</version>
        </dependency>

        <dependency>
            <groupId>com.google.guava</groupId>
            <artifactId>guava</artifactId>
            <version>17.0</version>
        </dependency>

        <dependency>
            <groupId>com.google.inject</groupId>
            <artifactId>guice</artifactId>
            <version>3.0</version>
        </dependency>

        <dependency>
            <groupId>com.google.appengine</groupId>
            <artifactId>appengine-api-1.0-sdk</artifactId>
            <version>${appengine.target.version}</version>
        </dependency>

        <dependency>
            <groupId>com.google.appengine.tools</groupId>
            <artifactId>appengine-gcs-client</artifactId>
            <version>0.4</version>
        </dependency>

        <dependency>
            <groupId>com.googlecode.objectify</groupId>
            <artifactId>objectify</artifactId>
            <version>5.0.3</version>
        </dependency>

        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>servlet-api</artifactId>
            <version>2.5</version>
            <scope>provided</scope>
        </dependency>

        <dependency>
            <groupId>org.jboss.resteasy</groupId>
            <artifactId>jaxrs-api</artifactId>
            <version>${resteasy.version}</version>
        </dependency>

        <dependency>
            <groupId>org.jboss.resteasy</groupId>
            <artifactId>resteasy-jaxrs</artifactId>
            <version>${resteasy.version}</version>
        </dependency>

        <dependency>
            <groupId>org.jboss.resteasy</groupId>
            <artifactId>resteasy-jackson2-provider</artifactId>
            <version>${resteasy.version}</version>
        </dependency>

        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-core</artifactId>
            <version>${jackson.version}</version>
        </dependency>

        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>${jackson.version}</version>
        </dependency>

        <dependency>
            <groupId>com.fasterxml.jackson.jaxrs</groupId>
            <artifactId>jackson-jaxrs-json-provider</artifactId>
            <version>${jackson.version}</version>
        </dependency>

        <!-- Test Dependencies -->

        <dependency>
            <groupId>com.google.appengine</groupId>
            <artifactId>appengine-testing</artifactId>
            <version>${appengine.target.version}</version>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>com.google.appengine</groupId>
            <artifactId>appengine-api-stubs</artifactId>
            <version>${appengine.target.version}</version>
            <scope>test</scope>
        </dependency>

    </dependencies>

</dependencyManagement>

依赖关系

<dependencies>

    <dependency>
        <groupId>com.google.code.findbugs</groupId>
        <artifactId>findbugs</artifactId>
    </dependency>

    <dependency>
        <groupId>org.reflections</groupId>
        <artifactId>reflections</artifactId>
    </dependency>

    <dependency>
        <groupId>com.google.guava</groupId>
        <artifactId>guava</artifactId>
    </dependency>

    <dependency>
        <groupId>com.google.inject</groupId>
        <artifactId>guice</artifactId>
    </dependency>

    <dependency>
        <groupId>com.google.appengine</groupId>
        <artifactId>appengine-api-1.0-sdk</artifactId>
        <version>${appengine.target.version}</version>
    </dependency>

    <dependency>
        <groupId>com.google.appengine.tools</groupId>
        <artifactId>appengine-gcs-client</artifactId>
        <version>0.4</version>
    </dependency>

    <dependency>
        <groupId>com.googlecode.objectify</groupId>
        <artifactId>objectify</artifactId>
        <version>5.0.3</version>
    </dependency>

    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>servlet-api</artifactId>
        <version>2.5</version>
        <scope>provided</scope>
    </dependency>

    <dependency>
        <groupId>org.jboss.resteasy</groupId>
        <artifactId>jaxrs-api</artifactId>
        <version>${resteasy.version}</version>
    </dependency>

    <dependency>
        <groupId>org.jboss.resteasy</groupId>
        <artifactId>resteasy-jaxrs</artifactId>
        <version>${resteasy.version}</version>
    </dependency>

    <dependency>
        <groupId>org.jboss.resteasy</groupId>
        <artifactId>resteasy-jackson2-provider</artifactId>
        <version>${resteasy.version}</version>
    </dependency>

    <dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-core</artifactId>
        <version>${jackson.version}</version>
    </dependency>

    <dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-databind</artifactId>
        <version>${jackson.version}</version>
    </dependency>

    <dependency>
        <groupId>com.fasterxml.jackson.jaxrs</groupId>
        <artifactId>jackson-jaxrs-json-provider</artifactId>
        <version>${jackson.version}</version>
    </dependency>

    <!-- Test Dependencies -->

    <dependency>
        <groupId>com.google.appengine</groupId>
        <artifactId>appengine-testing</artifactId>
        <version>${appengine.target.version}</version>
        <scope>test</scope>
    </dependency>

    <dependency>
        <groupId>com.google.appengine</groupId>
        <artifactId>appengine-api-stubs</artifactId>
        <version>${appengine.target.version}</version>
        <scope>test</scope>
    </dependency>

</dependencies>

【讨论】：

我已经添加了 <dependencyManagement> 标签，我错过了，但仍然没有运气。我所依赖的自定义项目都没有使用 jackson 的 fasterxml 包，尽管它们确实使用了较旧的 codehaus 包。
旧的 codehaus 包是你的问题，它们已经过时了，你应该移到最新版本。
我会尝试这种方法。我认为这不是问题，因为它为com.fasterxml 而不是org.codehaus 抛出错误。
你需要从头开始，网上没人能解决你的问题

【解决方案2】：

为我工作：

首先，检查并删除项目中具有这些名称的所有库：

Jackson Databind 
Jackson Core
Jackson Annotations

因为您可能会在您的 java 项目中重复其中一些 ..

第二，去这里http://mvnrepository.com/artifact/com.fasterxml.jackson.core 并下载具有 此特定 版本的 3 个 jars（28/04/2016 是最后一个版本）：

Jackson Databind  - version 2.73   
Jackson Core   - version 2.73     
Jackson Annotations   - version 2.73

第三，为你的控制器导入

 import com.fasterxml.jackson.core.JsonProcessingException;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.ObjectWriter;
...

ObjectWriter ow = new ObjectMapper().writer().withDefaultPrettyPrinter();
String json = json = ow.writeValueAsString(object);

不要忘记你的对象

@XmlRootElement(name = "UsuarioDTO")
@XmlAccessorType(XmlAccessType.FIELD)
public class UserDto implements Serializable {
...
}

-重建/重新部署（和调试，因为也许你会得到一个不同的错误，并可能与前一个混淆）

【讨论】：