com.google.gson.Gson.newJsonWriter 上的 Retrofit 2 的 java.lang.IllegalAccessError

Question

如何找出导致此 IllegalAccessError 问题的原因？感谢您的帮助。

我已经遵循了一些修复/解决方法并使用了 Maven 的 Gson 2.8。这是部分 Maven 配置:

<dependency>
    <groupId>com.squareup.retrofit2</groupId>
    <artifactId>converter-gson</artifactId>
    <version>2.2.0</version>
    <exclusions>
        <exclusion>
            <groupId>com.google.code.gson</groupId>
            <artifactId>gson</artifactId>
        </exclusion>
    </exclusions>
</dependency>

<dependency>
    <groupId>com.google.code.gson</groupId>
    <artifactId>gson</artifactId>
    <version>2.8.0</version>
</dependency>

和完整的堆栈跟踪:

java.lang.IllegalAccessError: tried to access method com.google.gson.Gson.newJsonWriter(Ljava/io/Writer;)Lcom/google/gson/stream/JsonWriter; from class retrofit2.converter.gson.GsonRequestBodyConverter
    at retrofit2.converter.gson.GsonRequestBodyConverter.convert(GsonRequestBodyConverter.java:45)
    at retrofit2.converter.gson.GsonRequestBodyConverter.convert(GsonRequestBodyConverter.java:30)
    at retrofit2.ParameterHandler$Body.apply(ParameterHandler.java:312)
    at retrofit2.ServiceMethod.toRequest(ServiceMethod.java:110)
    at retrofit2.OkHttpCall.createRawCall(OkHttpCall.java:178)
    at retrofit2.OkHttpCall.execute(OkHttpCall.java:162)
    at com.xxxxxx.web.controller.UserController.exchangeAccessToken(UserController.java:2551)
    at com.xxxxxx.web.controller.UserController.plaidtoken(UserController.java:2645)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.springframework.web.method.support.InvocableHandlerMethod.invoke(InvocableHandlerMethod.java:215)
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:132)
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:104)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:745)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:685)
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:80)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:919)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:851)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:953)
    at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:855)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:661)
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:829)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:742)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:230)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165)
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:106)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:478)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:80)
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:624)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:341)
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:799)
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:861)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1455)
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:745)

Answer 1

根据 IllegalAccessError 文档:

Thrown if an application attempts to access or modify a field, or to call a method that it does not have access to.

...this error can only occur at run time if the definition of a class has incompatibly changed.

在您的情况下，异常是在运行时抛出的，这意味着在编译时类路径与运行时的类路径不同。

一般情况下此类问题可以通过分析传递依赖来解决，可以使用maven dependency plugin :

mvn dependency:tree

您很可能会发现某些库中的传递依赖性与 gson 版本与您声明的版本不同。

注意:如果您替换其中一个传递依赖项，则很有可能会阻止其他内容。对此要小心，并确保您使用的是兼容的库。