怎么来的`.readEntity（MyObj.class）`失败而`objectMapper.readValue（STR，MyObj.class）;`工作

Question

我有这样的代码

import javax.ws.rs.core.GenericType; 
import javax.ws.rs.core.MediaType; 
import java.io.InputStream; 

import com.fasterxml.jackson.databind.ObjectMapper; 
import java.io.IOException; 
import java.util.Map; 
/** 
* Created by eladb on 9/6/16. 
*/ 
public class DeploymentClient { 

    private CommonClient commonClient; 


    String appName = "topic-test-publisher"; 


    public DeploymentClient(String url, InputStream clientSecretFile) { 
     commonClient = new CommonClient(url, clientSecretFile); 
    } 

    public VersionOld getCurrentConfigVersion(String project, String subDir) throws Exception { 
     VersionOld version = commonClient.authorizedRequestBuilder(commonClient.webTarget 
       .path("/apps/get_current_version/default/"+appName+"/"+appName) 
       .queryParam("object_type", "app")) 
       .accept(MediaType.APPLICATION_JSON_TYPE) 
       .get(ClientResponse.class) 
       .readEntity(VersionOld.class); 

     return null; 
    } 
} 

和

这给我说，例外：

javax.ws.rs.client.ResponseProcessingException: com.fasterxml.jackson.databind.JsonMappingException: Can not find a deserializer for non-concrete Map type [map type; class javax.ws.rs.core.MultivaluedMap, [simple type, class java.lang.String] -> [collection type; class java.util.List, contains [simple type, class java.lang.Object]]] 

at org.glassfish.jersey.client.JerseyInvocation.translate(JerseyInvocation.java:806) 
at org.glassfish.jersey.client.JerseyInvocation.access$700(JerseyInvocation.java:92) 
at org.glassfish.jersey.client.JerseyInvocation$2.call(JerseyInvocation.java:700) 
at org.glassfish.jersey.internal.Errors.process(Errors.java:315) 
at org.glassfish.jersey.internal.Errors.process(Errors.java:297) 
at org.glassfish.jersey.internal.Errors.process(Errors.java:228) 
at org.glassfish.jersey.process.internal.RequestScope.runInScope(RequestScope.java:444) 
at org.glassfish.jersey.client.JerseyInvocation.invoke(JerseyInvocation.java:696) 
at org.glassfish.jersey.client.JerseyInvocation$Builder.method(JerseyInvocation.java:420) 
at org.glassfish.jersey.client.JerseyInvocation$Builder.get(JerseyInvocation.java:316) 

但此代码的工作：

import javax.ws.rs.core.GenericType; 
import javax.ws.rs.core.MediaType; 
import java.io.InputStream; 

import com.fasterxml.jackson.databind.ObjectMapper; 
import java.io.IOException; 
import java.util.Map; 
/** 
* Created by eladb on 9/6/16. 
*/ 
public class DeploymentClient { 

    private CommonClient commonClient; 


    String appName = "topic-test-publisher"; 


    public DeploymentClient(String url, InputStream clientSecretFile) { 
     commonClient = new CommonClient(url, clientSecretFile); 
    } 

    public VersionOld getCurrentConfigVersion(String project, String subDir) throws Exception { 
     String str = commonClient.authorizedRequestBuilder(commonClient.webTarget 
       .path("/apps/get_current_version/default/"+appName+"/"+appName) 
       .queryParam("object_type", "app")) 
       .accept(MediaType.APPLICATION_JSON_TYPE) 
       .get() 
       .readEntity(String.class); 



     VersionOld v = foo(str); 
     return null; 
    } 

    public VersionOld foo(String str){ 
      ObjectMapper objectMapper = new ObjectMapper(); 
     VersionOld v = null; 
     try { 
      v = objectMapper.readValue(str, VersionOld.class); 
     } catch (Exception e) { 
      e.printStackTrace(); 
     } 
     return v; 
    } 
} 

在这两种情况下，http响应为：

str = {"versions": {"ap": "Not Set", "am": "topic-test-publisher-1.0.16", "il": "topic-test-publisher-1.0.16", "row": "topic-test-publisher-1.0.49"}, "provider": "gce"} 

该代码如何工作正常？

这不是一回事吗？

Answer 1

只需将ClientResponse替换为客户端代码中的javax.ws.rs.core.Response，或者根本不使用任何参数。

VersionOld version = commonClient.authorizedRequestBuilder(commonClient.webTarget 
      .path("/apps/get_current_version/default/"+appName+"/"+appName) 
      .queryParam("object_type", "app")) 
      .accept(MediaType.APPLICATION_JSON_TYPE) 
      .get(javax.ws.rs.core.Response.class)//or get().readEntity(VersionOld.class); 
      .readEntity(VersionOld.class); 

我相信你使用org.glassfish.jersey.client.ClientResponse但资源返回大概是javax.ws.rs.core.Response（它发生在我身上也）

我用下面的服务器端代码

@GET 
@Path("/us") 
@Produces(MediaType.APPLICATION_JSON) 
public Response getJson() { //javax.ws.rs.core.Response 
    VersionOld vo = new VersionOld(); 
    vo.versions.put("ap", "Not set"); 
    vo.versions.put("am", "topic-test-publisher-1.0.16"); 
    vo.versions.put("il", "topic-test-publisher-1.0.16"); 
    vo.versions.put("row", "topic-test-publisher-1.0.49"); 
    vo.provider = "gce"; 


    return Response.status(200).entity(vo).build(); 
} 

测试和POJO被定义为

public class VersionOld { 

    //public variables but you can use getters/setters 
public Map<String,String> versions = new HashMap<>(); 
public String provider; 

public VersionOld(){} 
    } 

输出是

Msg: topic-test-publisher-1.0.16 
Msg: topic-test-publisher-1.0.49