Jersey - 修改资源内的查询参数

Question

我在 ResourceA 中调用 ResourceB。

两者都使用相同的查询参数“param1”。

如何在调用 ResourceB 之前更改 ResourceA 中“param1”的值。

代码如下：

package com.example;

import javax.ws.rs.QueryParam;
import javax.ws.rs.core.Context;
import javax.ws.rs.core.Request;
import javax.ws.rs.core.Response;
import javax.ws.rs.core.Response.ResponseBuilder;

import net.sf.json.JSONArray;
import net.sf.json.JSONObject;

import com.sun.jersey.api.core.ResourceContext;

public abstract class MyResource {
    ResponseBuilder response;
    Request request;
    protected String param1;

    public MyResource(@QueryParam("param1") String param1, @Context Request request) {
        this.param1 = param1;
        this.request = request;
        this.response = Response.ok();
    }
}

public class ResourceA extends MyResource {
    public ResourceA(String param1, Request request) {
        super(param1, request);
    }
    @Context private ResourceContext rc;
    public Response postJSON(String postData) {
        JSONObject data = JSONObject.fromObject(postData);
        if (data.has("resourceB")) {
            ResourceB resourceB = rc.getResource(ResourceB.class);
            // resourceB.setQueryParams("param1", "my new param 1");
            resourceB.postJSON(data.getJSONArray("resourceB"));
        }
    }
}

public class ResourceB extends MyResource {
    public ResourceB(String param1, Request request) {
        super(param1, request);
    }

    public Response postJSON(JSONArray data) {
        // this.params1 should not be "my new param 1"
    }
}

Answer 1

如何使用ResourceContext.initResource(T resource)，使用修改后的值初始化资源，并通过声明 JAX-RS 注释字段来控制 DI 提供程序注入的内容？
如果我正确理解您的问题，您想在找到匹配的资源方法后修改请求上下文或挂钩注入并更改一些值。我不确定这是否可能。

但是，正如我所建议的，如果可以进行一些设计修改，您可以以编程方式初始化资源并利用仅注入字段：

public Response postJSON(String postData) {
    JSONObject data = JSONObject.fromObject(postData);
    if (data.has("resourceB")) {
        ResourceB resourceB = new ResourceB(/* pass here the modified query param */ "my new param 1");
        // let the DI provider inject the JAX-RS annotated fields only
        resourceB = rc.initResource(resourceB);
        // resourceB.setQueryParams("param1", "my new param 1");
        resourceB.postJSON(data.getJSONArray("resourceB"));
    }
}

ResourceB 类本身（及其超类）将声明您希望注入的注释字段，而@QueryParam("param1")（可能还有其他 JAX-RS 感知字段）将是在构造函数中声明，这样它就不会被覆盖。

public abstract class MyResource {
    ResponseBuilder response;

    // this gets injected in the ResourceContext.initResource() method
    @Context
    Request request;

    // additional JAX-RS annotated fields you would like to have injected such as
    @PathParam("id")
    private String pathParamId;

    protected String param1;

    // constructor JAX-RS annotated parameters would not get re-initialized  
    public MyResource(@QueryParam("param1") String param1) {
        this.param1 = param1;
        this.request = request;
        this.response = Response.ok();
    }
}