java - 如何以线程安全的方式在 JAX-RS 资源中使用 JerseyClient

Question

在以下UserResource类中:

public class UserResource {
    @POST
    @Consumes(MediaType.APPLICATION_JSON)
    @Produces(MediaType.APPLICATION_JSON)
    @Path("/users")
    public void createUser() {
        //JerseyClient is needed to send a REST request to another RESTful service
    }
}

JerseyClient 需要将请求发送到评论中提到的另一个 RESTful API。

由于可能有多个线程同时调用此 UserResource，因此 JerseyClient 可能应该在每个线程的每次调用中初始化，以确保线程安全。然而，JAX-RS Client提到过

Clients are heavy-weight objects that manage the client-side communication infrastructure. Initialization as well as disposal of a Client instance may be a rather expensive operation. It is therefore advised to construct only a small number of Client instances in the application. Client instances must be properly closed before being disposed to avoid leaking resources.

根据文档，在createUser主体内初始化JerseyClient可能会昂贵，从而带来性能问题。

问题:如何以线程安全的方式高效优化JerseyClient实例的数量？

Answer 1

如果将 Client 实例化为类字段就足够了，因为 Client 类是线程安全的。

Jersey documentation说:

Client instances are expensive resources. It is recommended a configured instance is reused for thecreation of Web resources. The creation of Web resources, the building of requests and receiving ofresponses are guaranteed to be thread safe. Thus a Client instance and WebResource instances maybe shared between multiple threads.