生成云端点类时的 InvocationTargetException

Question

当我单击生成云端点客户端库时，我在错误日志中收到以下内容。

java.lang.reflect.InvocationTargetException
    at com.google.gdt.eclipse.appengine.swarm.wizards.GenerateSwarmApiAction$1.run(GenerateSwarmApiAction.java:82)
    at org.eclipse.jface.operation.ModalContext$ModalContextThread.run(ModalContext.java:122)
Caused by: com.google.gdt.eclipse.appengine.swarm.wizards.helpers.SwarmGenerationException: com.google.api.server.spi.config.validation.MissingParameterNameException: tuberservice.com.rune.tuber.server.TuberServiceImpl.TuberServiceImpl.getInitParameter parameter (type class java.lang.String): Missing parameter name. Parameter type (class java.lang.String) is not an entity type and thus should be annotated with @Named.
    at com.google.gdt.eclipse.appengine.swarm.wizards.helpers.SwarmApiCreator.createSwarmApi(SwarmApiCreator.java:292)
    at com.google.gdt.eclipse.appengine.swarm.wizards.helpers.SwarmServiceCreator.create(SwarmServiceCreator.java:444)
    at com.google.gdt.eclipse.appengine.swarm.wizards.GenerateSwarmApiAction$1.run(GenerateSwarmApiAction.java:80)
    ... 1 more
Caused by: com.google.api.server.spi.config.validation.MissingParameterNameException: tuberservice.com.rune.tuber.server.TuberServiceImpl.TuberServiceImpl.getInitParameter parameter (type class java.lang.String): Missing parameter name. Parameter type (class java.lang.String) is not an entity type and thus should be annotated with @Named.
    at com.google.api.server.spi.config.validation.ApiConfigValidator.validateApiParameter(ApiConfigValidator.java:271)
    at com.google.api.server.spi.config.validation.ApiConfigValidator.validateParameter(ApiConfigValidator.java:229)
    at com.google.api.server.spi.config.validation.ApiConfigValidator.validateMethod(ApiConfigValidator.java:169)
    at com.google.api.server.spi.config.validation.ApiConfigValidator.validateMethods(ApiConfigValidator.java:130)
    at com.google.api.server.spi.config.validation.ApiConfigValidator.validate(ApiConfigValidator.java:93)
    at com.google.api.server.spi.config.validation.ApiConfigValidator.validate(ApiConfigValidator.java:63)
    at com.google.api.server.spi.config.jsonwriter.JsonConfigWriter.writeConfig(JsonConfigWriter.java:102)
    at com.google.api.server.spi.tools.AnnotationApiConfigGenerator.generateConfig(AnnotationApiConfigGenerator.java:62)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at com.google.gdt.eclipse.appengine.swarm.wizards.helpers.SwarmApiCreator.createSwarmApi(SwarmApiCreator.java:288)
    ... 3 more

这是我的服务实现

@SuppressWarnings("serial")
@Api(name = "tuberservice")
public class TuberServiceImpl extends RemoteServiceServlet implements
        TuberService {

    @Override
    @ApiMethod(name = "addClient")
    public String addClientService(TuberClient t) {
        if (t != null){
            PersistenceManager pm = PMF.get().getPersistenceManager();
            pm.makePersistent(t);
            pm.close();
            return t.toString();
        }
        return "Invalid client";
    }

    @SuppressWarnings("unchecked")
    @Override
    @ApiMethod(name = "listClients")
    public TuberClient[] listAllClientsService() {
        // TODO Auto-generated method stub
        //select from TuberClient
        PersistenceManager pm = PMF.get().getPersistenceManager();
        Query q = pm.newQuery(TuberClient.class);
        List<TuberClient> list = (List<TuberClient>) q.execute();
        ArrayList<TuberClient> returnList = new ArrayList<TuberClient>();
        for (TuberClient t : list){
            returnList.add(t);
        }//end for
        pm.close();
        return (TuberClient[])returnList.toArray(new TuberClient[0]);
    }

}

我已经为这个问题寻找了几个小时的解决方案。我尝试恢复到 appengine1.8.8，但它没有用，我尝试重建、清理等，没有，我什至尝试部署到 appengine，但没有用。

我真的不知道从哪里开始解决错误，因为我的服务器实现中没有任何要注释的字符串，所以我总体上很困惑。

Answer 1

您不能从 Cloud Endpoints 方法返回 String。

这行不会编译：

public String addClientService(TuberClient t)

这也很可疑：

extends RemoteServiceServlet implements TuberService

检查那里是否没有任何返回 String 的 API 方法。

请阅读此guide。仔细检查您的代码是否返回有效值，并且每个必需参数都有对应的 @Name 注释。

Endpoint方法中，返回值类型不能是简单类型 如字符串或整数。返回值需要是一个POJO，一个数组 或集合。此外，list() 和 get() 公开为 HTTP GET， insert() 公开为 HTTP POST，update() 公开为 HTTP PUT， 并且 removeNote() 被暴露为 HTTP DELETE。