Question

这是我Rest端点的样子

  @Post("json")
  public List<LogProcessorExpression> addLogProcessorExpression(
      final List<LogProcessorExpression> expressions) throws LPRestletException {
    if (expressions == null || expressions.isEmpty()) {
      return Collections.emptyList();
    }

    final Integer currentTenantId = Utils.getCurrentTenantId(getRequest());
    return customAttributesManager.addLogProcessorExpression(currentTenantId, expressions);
  }

它调用的方法看起来像

List<LogProcessorExpression> addLogProcessorExpression(final Integer currentTenantId,
                                                       final List<LogProcessorExpression> expressions)
      throws LPRestletException {
    final Map<String, LogProcessorExpression> cache = getCacheByCustomAttributeName(expressions);
    try {
      final List<Customattributesmetadata> cams =
          getCustomAttributesMetaDataForTenant(currentTenantId);

      for (final Customattributesmetadata metadata : cams) {
        if (cache.containsKey(metadata.getAttributecolumnname())) {
          metadata.setLogprocessorexpression(
              cache.get(metadata.getAttributecolumnname()).toString());
        }
        metadata.save();
      }
    } catch (final TorqueException e) {
      final String error = "Failed to update LogExpression custom attributes";
      LOGGER.error(error, e);
      throw new LPRestletException(error, e);
    }

    return expressions;
  }

调用链中的其他方法。我在访问此端点时意识到的是

 curl -v -H "Authorization:Basic Y3VyYasqrwqrjQGdtYWlsLmNvbTp0YXAzYWg=" \
     -H "Content-Type:application/json" \
     -d '[{"source": "ad", "attributePrefix": "ad_", "attributeName": "department"}]' \
     http://172.11.041.240:8080/api/rest/msp/attributes

它返回

{
   "code" : 500
   "message" : "The server encountered an unexpected condition which prevented it from fulfilling the request",
}

当我查看日志时，我看到行为

        at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1515)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
        at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
        at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.ClassCastException: java.util.LinkedHashMap cannot be cast to com.shn.api.dto.LogProcessorExpression
        at com.shn.api.restlet.logprocessor.CustomAttributesManager.getCacheByCustomAttributeName(CustomAttributesManager.java:55)
        at com.shn.api.restlet.logprocessor.CustomAttributesManager.addLogProcessorExpression(CustomAttributesManager.java:24)
        at com.shn.api.restlet.logprocessor.CustomAttributeMetadataRestlet.addLogProcessorExpression(CustomAttributeMetadataRestlet.java:44)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:606)
        at org.restlet.resource.ServerResource.doHandle(ServerResource.java:521)
        ... 67 more

问题
- 为什么不将它们投射到List<LogProcessorExpression>？ - 我需要做些什么来解决它？

更新

第24行看起来像

final Map<String, LogProcessorExpression> cache = getCacheByCustomAttributeName(expressions);

第44行看起来像

return customAttributesManager.addLogProcessorExpression(currentTenantId, expressions);

getCacheByCustomAttributeName(expressions)看起来像

  Map<String, LogProcessorExpression> getCacheByCustomAttributeName(
      final List<LogProcessorExpression> expressions) {
    if (expressions == null || expressions.isEmpty()) {
      return Collections.emptyMap();
    }

    final Map<String, LogProcessorExpression> attributeByExpression = new HashMap<>();
    for (final LogProcessorExpression expression : expressions) {
      attributeByExpression.put(expression.getAttributeName(), expression);
    }
    return attributeByExpression;
  }

Answer 1

我认为restlet可能不够复杂，无法从处理程序方法的参数列表中提取参数化类型List<LogProcessorExpression>。

@Post("json")
public List<LogProcessorExpression> addLogProcessorExpression(
  final List<LogProcessorExpression> expressions)

它只需要List，并且可能在反序列化时使用它（使用Jackson）。当没有提供时，杰克逊使用LinkedHashMap作为反序列化目标类型。

如果不能更好地实现这一点（可能是在更新的版本中？），可能的解决方案是定义自定义类型

class LogProcessorExpressionList extends ArrayList<LogProcessorExpression> {}

并将该类型用作参数类型

@Post("json")
public List<LogProcessorExpression> addLogProcessorExpression(
  final LogProcessorExpressionList expressions)

杰克逊然后可以提取LogProcessorExpressionList类型的参数化超类型，它是ArrayList<LogProcessorExpression>，从中可以提取LogProcessorExpression作为目标元素类型。

Answer 2

也许您可以使用自定义Jackson解串器吗？有关此功能，请参阅此链接：http://www.baeldung.com/jackson-deserialization。

这个答案为您提供了配置杰克逊ObjectMapper：How to register Jackson Jdk8 module in Restlet的一些提示。这允许注册自定义反序列化器并参与反序列化处理以在列表中创建正确的对象。

希望它可以帮到你，亨利

Answer 3

这对我有用..

class LogProcessorExpressionList extends ArrayList<LogProcessorExpression> {}

Restlet将JSON转换为LinkedHashMap而不是List <myobject>？

3 个答案: