Java / Jersey方法

Question

这是我在Java中的第一个API，所以请记住这一点;)我有Controller.class，我现在保存我所有的方法(稍后我会清理它;)就GET方法而言，当我想要创建新用户时，我对PUT方法有问题--它不起作用。有什么帮助吗？和建议的原因--正如我所说--我在API方面是新手;)

这是我的controller.class：

 @Path("/api")
public class Controller {

    List<Post> mBartoszPosts;
    List<Post> mFelipePosts;
    List<Post> mShawnPosts;
    List<Post> mDavidPosts;
    List<Post> mGraziellaPosts;
    List<Post> mAllPosts;


    List<User> mUsers;
    User bartosz;
    User felipe;
    User shawn;
    User david;
    User graziella;



      @Path("/user/{id}")
      @GET
      @Produces("application/json")
     public Response  getUser(@PathParam("id")int id) {
         setUpUsers();
         System.out.println("Liczba osob : " + mUsers.size());
         for(User user : mUsers) {
            if(id == user.getId()) {
                String result = user.toString();
             return Response.status(200).entity(user).build();
            }
         } 
        return null;
         }
      @Path("/post/{post_id}")
      @GET
      @Produces("application/json")
     public Response  getPost(@PathParam("post_id")int post_id) {
         setUpUsers();
         System.out.println("Liczba osob : " + mUsers.size());
         for(Post post : mAllPosts) {
            if(post_id == post.getId()) {
                String result = post.toString();
             return Response.status(200).entity(post).build();
            }
         } 
        return null;

         }
      @Path("/posts")
      @GET
      @Produces("application/json")
     public Response  getPosts() {
         setUpUsers();
         String response = new Gson().toJson(mAllPosts );
             return Response.status(200).entity(response).build();

         }

      @PUT
      @Path("user/new/{id}/{post}")
      @Consumes(MediaType.APPLICATION_XML)
      @Produces(MediaType.APPLICATION_XML)
      public Response updateEmployeeById(@PathParam("id") Integer id,@PathParam("post") String userPost) 
      {
          List<Post>userPosts = new ArrayList();
          Post post = new Post(99,userPost,"Bartosz");
          userPosts.add(post);
          User updatedEmployee = new User(id,"Bartek","Szlapa",userPosts);

          if(updatedEmployee.getName() == null) {
              return Response.status(400).entity("Please provide the employee name !!").build();
          }

          updatedEmployee.setId(id);
          updatedEmployee.setName(updatedEmployee.getName());
          System.out.println(updatedEmployee.getName());

          return Response.ok().entity(updatedEmployee).build();
      }

      public int maxValue(int array[]){
          int max = Arrays.stream(array).max().getAsInt();
          return max;
        }
}

正如您所看到的，最后一个方法是PUT，但它不起作用:下面是我的测试客户端：

public class Test {

    public static void main(String[] args) {
        // TODO Auto-generated method stub

        Client client = ClientBuilder.newClient( new ClientConfig().register( Controller.class ) );
        WebTarget webTarget = client.target("http://localhost:8080/JerseyDemos/rest").path("api").path("user").path("new").path("77");
        List<Post>userPosts = new ArrayList();
        Post post = new Post(99,"Bartek Szlapa","Testing post ...");
        userPosts.add(post);
        User emp = new User(99,"Bartek","Szlapa",userPosts);
        Invocation.Builder invocationBuilder =  webTarget.request(MediaType.APPLICATION_XML);
        Response response = invocationBuilder.put(Entity.entity(emp, MediaType.APPLICATION_XML));
        User user = response.readEntity(User.class);
        System.out.println(response.getStatus());
        System.out.println(user);
    }
}

最后我的错误是：

Exception in thread "main" org.glassfish.jersey.message.internal.MessageBodyProviderNotFoundException: MessageBodyWriter not found for media type=application/xml, type=class entities.User, genericType=class entities.User.
    at org.glassfish.jersey.message.internal.WriterInterceptorExecutor$TerminalWriterInterceptor.aroundWriteTo(WriterInterceptorExecutor.java:248)
    at org.glassfish.jersey.message.internal.WriterInterceptorExecutor.proceed(WriterInterceptorExecutor.java:163)
    at org.glassfish.jersey.message.internal.MessageBodyFactory.writeTo(MessageBodyFactory.java:1135)
    at org.glassfish.jersey.client.ClientRequest.doWriteEntity(ClientRequest.java:516)
    at org.glassfish.jersey.client.ClientRequest.writeEntity(ClientRequest.java:498)
    at org.glassfish.jersey.client.internal.HttpUrlConnector._apply(HttpUrlConnector.java:384)
    at org.glassfish.jersey.client.internal.HttpUrlConnector.apply(HttpUrlConnector.java:282)
    at org.glassfish.jersey.client.ClientRuntime.invoke(ClientRuntime.java:278)
    at org.glassfish.jersey.client.JerseyInvocation.lambda$invoke$0(JerseyInvocation.java:753)
    at org.glassfish.jersey.internal.Errors.process(Errors.java:316)
    at org.glassfish.jersey.internal.Errors.process(Errors.java:298)
    at org.glassfish.jersey.internal.Errors.process(Errors.java:229)
    at org.glassfish.jersey.process.internal.RequestScope.runInScope(RequestScope.java:414)
    at org.glassfish.jersey.client.JerseyInvocation.invoke(JerseyInvocation.java:752)
    at org.glassfish.jersey.client.JerseyInvocation$Builder.method(JerseyInvocation.java:445)
    at org.glassfish.jersey.client.JerseyInvocation$Builder.put(JerseyInvocation.java:334)
    at test.Test.main(Test.java:33)

提前感谢您的帮助！

Answer 1

你的客户代码好像有两个问题-

1. 为了删除此错误，应在类路径中添加jersey-media-jaxb JAR。如果您正在使用maven，请在pom.xml中添加下面的依赖项- org.glassfish.jersey.media运动衫-媒体-jaxb ${jersey.version}
2. 根据您的PUT方法API规范-

public Response updateEmployeeById(@PathParam("id") Integer id,@PathParam("post") String userPost) {

您的REST服务只需要path parameter、id和post。不需要其他输入。但是，在客户端代码中，您是在调用API时发送User类对象emp对象-

Response response = invocationBuilder.put(Entity.entity(emp, MediaType.APPLICATION_XML));

因为您在API中没有接收到这个emp对象，所以这些数据将丢失。因此，要么应该更新API以接受请求中的User类对象，要么不要从客户端代码中发送该对象。