澤西錯誤：找不到媒體類型= application / json的MessageBodyReader

Question

我正在嘗試使用Jersey作為框架來實現小型REST API，原則上代碼可以正常工作，但是當我嘗試對哈希表執行“ GET”操作時，出現以下錯誤：

nov 23, 2014 4:27:40 PM org.glassfish.jersey.message.internal.ReaderInterceptorExecutor$TerminalReaderInterceptor aroundReadFrom
GRAVE: MessageBodyReader not found for media type=application/json, type=interface java.util.Map, genericType=java.util.Map<upf.dad.proyecto.New, upf.dad.proyecto.Term>.
1440 [DefaultQuartzScheduler_Worker-3] ERROR org.quartz.core.JobRunShell - Job DEFAULT.testJob3 threw an unhandled Exception: 
org.glassfish.jersey.message.internal.MessageBodyProviderNotFoundException: MessageBodyReader not found for media type=application/json, type=interface java.util.Map, genericType=java.util.Map<upf.dad.proyecto.New, upf.dad.proyecto.Term>.
    at org.glassfish.jersey.message.internal.ReaderInterceptorExecutor$TerminalReaderInterceptor.aroundReadFrom(ReaderInterceptorExecutor.java:230)
    at org.glassfish.jersey.message.internal.ReaderInterceptorExecutor.proceed(ReaderInterceptorExecutor.java:154)
    at org.glassfish.jersey.message.internal.MessageBodyFactory.readFrom(MessageBodyFactory.java:1124)
    at org.glassfish.jersey.message.internal.InboundMessageContext.readEntity(InboundMessageContext.java:851)
    at org.glassfish.jersey.message.internal.InboundMessageContext.readEntity(InboundMessageContext.java:810)
)
    at org.glassfish.jersey.client.JerseyInvocation$Builder.get(JerseyInvocation.java:313)
    at upf.dad.proyecto.HotTopicDetector.News(HotTopicDetector.java:110)
    at upf.dad.proyecto.ScheduledTestJob3.execute(ScheduledTestJob3.java:11)
1440 [DefaultQuartzScheduler_Worker-3] ERROR org.quartz.core.ErrorLogger - Job (DEFAULT.testJob3 threw an exception.
org.quartz.SchedulerException: Job threw an unhandled exception. [See nested exception: org.glassfish.jersey.message.internal.MessageBodyProviderNotFoundException: MessageBodyReader not found for media type=application/json, type=interface java.util.Map, genericType=java.util.Map<upf.dad.proyecto.New, upf.dad.proyecto.Term>.]
    at org.quartz.core.JobRunShell.run(JobRunShell.java:213)
    at org.quartz.simpl.SimpleThreadPool$WorkerThread.run(SimpleThreadPool.java:573)
Caused by: org.glassfish.jersey.message.internal.MessageBodyProviderNotFoundException: MessageBodyReader not found for media type=application/json, type=interface java.util.Map, genericType=java.util.Map<upf.dad.proyecto.New, upf.dad.proyecto.Term>.
    at org.glassfish.jersey.message.internal.ReaderInterceptorExecutor$TerminalReaderInterceptor.aroundReadFrom(ReaderInterceptorExecutor.java:230)
    at org.glassfish.jersey.message.internal.ReaderInterceptorExecutor.proceed(ReaderInterceptorExecutor.java:154)
    at org.glassfish.jersey.message.internal.MessageBodyFactory.readFrom(MessageBodyFactory.java:1124)
    at org.glassfish.jersey.message.internal.InboundMessageContext.readEntity(InboundMessageContext.java:851)
    at org.glassfish.jersey.message.internal.InboundMessageContext.readEntity(InboundMessageContext.java:810)
    at org.glassfish.jersey.client.ClientResponse.readEntity(ClientResponse.java:368)
    at org.glassfish.jersey.client.JerseyInvocation.translate(JerseyInvocation.java:846)
    at org.glassfish.jersey.client.JerseyInvocation.access$600(JerseyInvocation.java:91)
    at org.glassfish.jersey.client.JerseyInvocation$3.call(JerseyInvocation.java:705)
    at org.glassfish.jersey.internal.Errors.process(Errors.java:315)
    at org.glassfish.jersey.internal.Errors.process(Errors.java:297)
    at org.glassfish.jersey.internal.Errors.process(Errors.java:228)
    at org.glassfish.jersey.process.internal.RequestScope.runInScope(RequestScope.java:424)
    at org.glassfish.jersey.client.JerseyInvocation.invoke(JerseyInvocation.java:701)
    at org.glassfish.jersey.client.JerseyInvocation$Builder.method(JerseyInvocation.java:417)
    at org.glassfish.jersey.client.JerseyInvocation$Builder.get(JerseyInvocation.java:313)
    at upf.dad.proyecto.HotTopicDetector.News(HotTopicDetector.java:110)
    at upf.dad.proyecto.ScheduledTestJob3.execute(ScheduledTestJob3.java:11)
    at org.quartz.core.JobRunShell.run(JobRunShell.java:202)
    ... 1 more

這是有問題的行：

    Client client = ClientBuilder.newClient();

    WebTarget targetGetAllNews = client.target("http://localhost:15000").path("news/getAllNews");


    Map<New, Term> NewsAll = targetGetAllNews.request(
             MediaType.APPLICATION_JSON_TYPE).get(new GenericType<Map<New, Term>>(){});

這就是我實現服務的方式：

@GET
@Path("/getAllNews")
@Produces(MediaType.APPLICATION_JSON)
public Map<New, Term> getAllNews() {
    return NewsCrawler.getNewAndTerm();
}

pom.xml（Maven依賴項）

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>upf.dad.proyecto</groupId>
<artifactId>JAXRS-proyecto</artifactId>
<version>0.0.1-SNAPSHOT</version>
<dependencies>
<!-- Rome RSS and Atom utilities @ http://rometools.github.io/rome/ -->        
<dependency>
        <groupId>rome</groupId>
        <artifactId>rome</artifactId>             
        <version>1.0</version>
</dependency>

<!-- jsoup HTML parser library @ http://jsoup.org/ -->         
<dependency>             
        <groupId>org.jsoup</groupId>             
        <artifactId>jsoup</artifactId>             
        <version>1.8.1</version>               
</dependency>
    <dependency>
        <groupId>org.quartz-scheduler</groupId>
        <artifactId>quartz</artifactId>
        <version>2.2.1</version>
    </dependency>
    <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>slf4j-simple</artifactId>
        <version>1.6.1</version>
    </dependency>
    <dependency>
        <groupId>org.twitter4j</groupId>
        <artifactId>twitter4j-core</artifactId>
        <version>4.0.2</version>
    </dependency>
    <dependency>
        <groupId>org.glassfish.jersey.containers</groupId>
        <artifactId>jersey-container-servlet</artifactId>
        <version>2.12</version>
    </dependency>
    <dependency>
        <groupId>org.glassfish.jersey.containers</groupId>
        <artifactId>jersey-container-jdk-http</artifactId>
        <version>2.12</version>
    </dependency>
    <dependency>
        <groupId>org.glassfish.jersey.media</groupId>
        <artifactId>jersey-media-moxy</artifactId>
        <version>2.12</version>
    </dependency>
    <dependency>
        <groupId>org.glassfish.jersey.core</groupId>
        <artifactId>jersey-client</artifactId>
        <version>2.12</version>
    </dependency>
    <dependency>
        <groupId>org.glassfish.jersey.media</groupId>
        <artifactId>jersey-media-json-jackson</artifactId>
        <version>2.13</version>
    </dependency>
</dependencies>
</project>

服務器端配置：

public class NewsCrawlerRestServer {

public static void main(String[] args) throws IOException {

    URI baseUri = UriBuilder.fromUri("http://localhost/").port(15000).build();
    ResourceConfig config = new ResourceConfig(NewsCrawlerServices.class, HotTopicDetectorServices.class);
    config.register(JacksonFeature.class);
    HttpServer server = JdkHttpServerFactory.createHttpServer(baseUri, config);
    System.out.println("Server started...");

    }
}

在客戶端中注冊Jackson時出錯：

org.quartz.SchedulerException: Job threw an unhandled exception. [See nested exception: javax.ws.rs.ProcessingException: Error reading entity from input stream.]
        at org.quartz.core.JobRunShell.run(JobRunShell.java:213)
        at org.quartz.simpl.SimpleThreadPool$WorkerThread.run(SimpleThreadPool.java:573)
    Caused by: javax.ws.rs.ProcessingException: Error reading entity from input stream.
        at org.glassfish.jersey.message.internal.InboundMessageContext.readEntity(InboundMessageContext.java:866)
        at org.glassfish.jersey.message.internal.InboundMessageContext.readEntity(InboundMessageContext.java:810)
        at org.glassfish.jersey.client.ClientResponse.readEntity(ClientResponse.java:368)
        at org.glassfish.jersey.client.JerseyInvocation.translate(JerseyInvocation.java:846)
        at org.glassfish.jersey.client.JerseyInvocation.access$600(JerseyInvocation.java:91)
        at org.glassfish.jersey.client.JerseyInvocation$3.call(JerseyInvocation.java:705)
        at org.glassfish.jersey.internal.Errors.process(Errors.java:315)
        at org.glassfish.jersey.internal.Errors.process(Errors.java:297)
        at org.glassfish.jersey.internal.Errors.process(Errors.java:228)
        at org.glassfish.jersey.process.internal.RequestScope.runInScope(RequestScope.java:424)
        at org.glassfish.jersey.client.JerseyInvocation.invoke(JerseyInvocation.java:701)
        at org.glassfish.jersey.client.JerseyInvocation$Builder.method(JerseyInvocation.java:417)
        at org.glassfish.jersey.client.JerseyInvocation$Builder.get(JerseyInvocation.java:313)
        at upf.dad.proyecto.HotTopicDetector.News(HotTopicDetector.java:112)
        at upf.dad.proyecto.ScheduledTestJob3.execute(ScheduledTestJob3.java:11)
        at org.quartz.core.JobRunShell.run(JobRunShell.java:202)
        ... 1 more
    Caused by: com.fasterxml.jackson.databind.JsonMappingException: Can not find a (Map) Key deserializer for type [simple type, class upf.dad.proyecto.New]
        at com.fasterxml.jackson.databind.deser.DeserializerCache._handleUnknownKeyDeserializer(DeserializerCache.java:580)
        at com.fasterxml.jackson.databind.deser.DeserializerCache.findKeyDeserializer(DeserializerCache.java:170)
        at com.fasterxml.jackson.databind.DeserializationContext.findKeyDeserializer(DeserializationContext.java:404)
        at com.fasterxml.jackson.databind.deser.std.MapDeserializer.createContextual(MapDeserializer.java:232)
        at com.fasterxml.jackson.databind.DeserializationContext.handleSecondaryContextualization(DeserializationContext.java:572)
        at com.fasterxml.jackson.databind.DeserializationContext.findRootValueDeserializer(DeserializationContext.java:386)
        at com.fasterxml.jackson.databind.ObjectReader._findRootDeserializer(ObjectReader.java:1380)
        at com.fasterxml.jackson.databind.ObjectReader._bind(ObjectReader.java:1228)
        at com.fasterxml.jackson.databind.ObjectReader.readValue(ObjectReader.java:677)
        at com.fasterxml.jackson.jaxrs.base.ProviderBase.readFrom(ProviderBase.java:777)
        at org.glassfish.jersey.message.internal.ReaderInterceptorExecutor$TerminalReaderInterceptor.invokeReadFrom(ReaderInterceptorExecutor.java:264)
        at org.glassfish.jersey.message.internal.ReaderInterceptorExecutor$TerminalReaderInterceptor.aroundReadFrom(ReaderInterceptorExecutor.java:234)
        at org.glassfish.jersey.message.internal.ReaderInterceptorExecutor.proceed(ReaderInterceptorExecutor.java:154)
        at org.glassfish.jersey.message.internal.MessageBodyFactory.readFrom(MessageBodyFactory.java:1124)
        at org.glassfish.jersey.message.internal.InboundMessageContext.readEntity(InboundMessageContext.java:851)

新課程：

package upf.dad.proyecto;

import java.util.Date;

public class New {

private String tittle;
private String description;
private Date date;
private String link;

public New(){

}

public New(String t, String d, Date date, String l){
    this.tittle = t;
    this.description = d;
    this.date = date;
    this.link = l;
}

public String getTittle() {
    return tittle;
}

public void setTittle(String tittle) {
    this.tittle = tittle;
}

public String getDescription() {
    return description;
}

public void setDescription(String description) {
    this.description = description;
}

public Date getDate() {
    return date;
}

public void setDate(Date date) {
    this.date = date;
}

public String getLink() {
    return link;
}

public void setLink(String link) {
    this.link = link;
}

@Override
public String toString() {
    return "New [tittle=" + tittle + ", description=" + description
            + ", date=" + date + ", link=" + link + "]";
}


}

學期班：

package upf.dad.proyecto;

public class Term {

private String word;

public Term(){

}

public Term(String word){
    this.word = word;

}

public String getWord(){
    return word;
}

public void setWord(String _word){
    word = _word;
}

@Override
public String toString() {
    return "Termino =" + word + "]";
}
}

有人可以幫我退回地圖嗎？

Answer 1

我看到您有兩個不同的提供程序依賴項jersey-media-moxy和jersey-media-json-jackson 。 我對MOXy的Maps一直有疑問。 我猜他們表現不好。 似乎您需要使用適配器才能使其正常運行，如Blaise Doughan所示 。

話雖如此，我要求（在上面的評論中）查看您的服務器端配置，因為MOXy會自動進行自我配置，並且優先於jersey-media-json-jackson 。 為什么我不確定，這就是我一直經歷的。 所以我很好奇，即使在響應返回到客戶端之前，服務器端也不會失敗。 除非您將JacksonFeature與服務器應用程序配置在一起，否則您還應該在其中與客戶端進行配置。 （只有這種情況，因為您還具有MOXy依賴性）。

無論如何，如上面的鏈接所示，如果您不想經歷創建適配器的麻煩，那么就擺脫jersey-media-moxy依賴性。 jersey-media-json-jackson也將自動配置該功能。 您應該只使用其中一個。

---

作為旁白：

@Path("/getAllNews") 。 路徑段應該是名詞，除非它們是控制器資源，除了正常的CRUD操作（例如/register ）外，它們通常會執行某些操作。 HTTP方法已經包含應對每個CRUD操作執行的動詞。

• çreate - POST
• [R etriecve - GET
• 更新 = PUT
• d elete -刪除

僅需考慮一些語義：-)

---

更新

問題出在New密鑰上。 傑克遜不知道該如何反序列化。 因為您願意切換鍵和值類型，所以只需更改toString返回Term類中的name ，就可以了。