我試圖將一個(gè)簡(jiǎn)單的json字符串解析成一個(gè)地圖,并試圖使用Jackson庫(kù)這樣做.到目前為止,這是我的代碼：

private static Map<String, String> handleJsonResponse(OAuthResourceResponse response) {
    JsonFactory factory = new JsonFactory();
    ObjectMapper mapper = new ObjectMapper();
    TypeFactory typeFactory = mapper.getTypeFactory();
    MapType mapType = typeFactory.constructMapType(HashMap.class, String.class, String.class);
    Map<String, String> result;

    JsonParser parser  = factory.createParser(response.getBody());
    result = mapper.readValues(parser, mapType);
}

但是,我收到一個(gè)錯(cuò)誤說(shuō)：

我試過(guò)這樣做：

result = mapper.readValues(parser, new TypeReference<Map<String, String>>() {});

但我得到與上面相同的結(jié)果.

最后,我試過(guò)這樣做：

result = (Map) mapper.readValues(parser, mapType);

但后來(lái)我得到一個(gè)運(yùn)行時(shí)錯(cuò)誤：

java.lang.RuntimeException: com.fasterxml.jackson.databind.MappingIterator cannot be cast to java.util.Map
    at app.security.oauth.OAuthUtils.handleJsonResponse(OAuthUtils.java:194) ~[classes/:na]
    at app.security.oauth.OAuthUtils.handleResponse(OAuthUtils.java:161) ~[classes/:na]
    at app.services.P2IdentityService.getMID(P2IdentityService.java:19) ~[classes/:na]
    at app.controllers.AlertController.getInformation(AlertController.java:18) ~[classes/:na]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_65]
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_65]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_65]
    at java.lang.reflect.Method.invoke(Method.java:497) ~[na:1.8.0_65]
    at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:222) ~[spring-web-4.2.3.RELEASE.jar:4.2.3.RELEASE]
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:137) ~[spring-web-4.2.3.RELEASE.jar:4.2.3.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:110) ~[spring-webmvc-4.2.3.RELEASE.jar:4.2.3.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:814) ~[spring-webmvc-4.2.3.RELEASE.jar:4.2.3.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:737) ~[spring-webmvc-4.2.3.RELEASE.jar:4.2.3.RELEASE]
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85) ~[spring-webmvc-4.2.3.RELEASE.jar:4.2.3.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:959) ~[spring-webmvc-4.2.3.RELEASE.jar:4.2.3.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:893) ~[spring-webmvc-4.2.3.RELEASE.jar:4.2.3.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970) ~[spring-webmvc-4.2.3.RELEASE.jar:4.2.3.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861) ~[spring-webmvc-4.2.3.RELEASE.jar:4.2.3.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:622) ~[tomcat-embed-core-8.0.28.jar:8.0.28]
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846) ~[spring-webmvc-4.2.3.RELEASE.jar:4.2.3.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:729) ~[tomcat-embed-core-8.0.28.jar:8.0.28]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291) ~[tomcat-embed-core-8.0.28.jar:8.0.28]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) ~[tomcat-embed-core-8.0.28.jar:8.0.28]
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) ~[tomcat-embed-websocket-8.0.28.jar:8.0.28]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239) ~[tomcat-embed-core-8.0.28.jar:8.0.28]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) ~[tomcat-embed-core-8.0.28.jar:8.0.28]
    at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99) ~[spring-web-4.2.3.RELEASE.jar:4.2.3.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.2.3.RELEASE.jar:4.2.3.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239) ~[tomcat-embed-core-8.0.28.jar:8.0.28]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) ~[tomcat-embed-core-8.0.28.jar:8.0.28]
    at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:87) ~[spring-web-4.2.3.RELEASE.jar:4.2.3.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.2.3.RELEASE.jar:4.2.3.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239) ~[tomcat-embed-core-8.0.28.jar:8.0.28]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) ~[tomcat-embed-core-8.0.28.jar:8.0.28]
    at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:77) ~[spring-web-4.2.3.RELEASE.jar:4.2.3.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.2.3.RELEASE.jar:4.2.3.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239) ~[tomcat-embed-core-8.0.28.jar:8.0.28]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) ~[tomcat-embed-core-8.0.28.jar:8.0.28]
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:121) ~[spring-web-4.2.3.RELEASE.jar:4.2.3.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.2.3.RELEASE.jar:4.2.3.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239) ~[tomcat-embed-core-8.0.28.jar:8.0.28]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) ~[tomcat-embed-core-8.0.28.jar:8.0.28]
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:217) ~[tomcat-embed-core-8.0.28.jar:8.0.28]
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106) [tomcat-embed-core-8.0.28.jar:8.0.28]
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502) [tomcat-embed-core-8.0.28.jar:8.0.28]
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:142) [tomcat-embed-core-8.0.28.jar:8.0.28]
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79) [tomcat-embed-core-8.0.28.jar:8.0.28]
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88) [tomcat-embed-core-8.0.28.jar:8.0.28]
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:518) [tomcat-embed-core-8.0.28.jar:8.0.28]
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1091) [tomcat-embed-core-8.0.28.jar:8.0.28]
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:673) [tomcat-embed-core-8.0.28.jar:8.0.28]
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1500) [tomcat-embed-core-8.0.28.jar:8.0.28]
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1456) [tomcat-embed-core-8.0.28.jar:8.0.28]
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [na:1.8.0_65]
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [na:1.8.0_65]
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-8.0.28.jar:8.0.28]
    at java.lang.Thread.run(Thread.java:745) [na:1.8.0_65]

知道我做錯(cuò)了什么嗎？

解決方法:

我只使用Spring Boot的原生json解析器解決了這個(gè)問(wèn)題：

org.springframework.boot.json.JsonParser springParser = JsonParserFactory.getJsonParser();
Map<String, Object> result = springParser.parseMap(response.getBody());

然而,真正的信用來(lái)自這篇文章：How to parse a dynamic JSON key in a Nested JSON result?