java - Angular 8 : Why do I receive null when using URL Query Strings?

Question

我正在尝试使用以下网络服务

@POST
@Path("/delete")
@Produces(MediaType.APPLICATION_JSON)
public boolean deletePost(@QueryParam("idPost") String idPost) {
// logic here
}

但是，尝试从 Angular 为 QueryParam idPost 分配值是行不通的。 idPost 始终以 null 值到达。

尝试文档中指定的两种形式，但它对我不起作用。我做错了什么？

public deletePost(idPost: number): Observable<any> {
    const options = idPost ?
    { params: new HttpParams().set('idPost', idPost.toString()) } : {};
    return this.httpClient.post('url-delete',options);
}

public deletePost(idPost: number): Observable<any> {
    const params = new HttpParams({fromString: 'idPost=' + idPost.toString()});
    return this.httpClient.post('url-delete',params);
}

Answer 1

post 中的第二个参数是正文，选项应该是一个 json，如下所示:

const options = { params: new HttpParams().set('name', 'xxx') }

现在像这样调用它:

public deletePost(idPost: number): Observable<any> {
    const options = {params: new HttpParams({fromString: 'idPost=' + idPost.toString()})};
    return this.httpClient.post('url-delete',{}, options); // empty body
}