Angular请求返回非json数据详解

Angular请求返回的数据默认是做json解析处理，如果返回的数据不是json格式，就会报错，如下：

Unexpected token O in JSON at position 0

这时候就要对请求的返回数据格式进行处理，如下： 如果需要返回非JSON数据，则需要在请求时设置responseType头信息为text：

Get请求：

return this.http.get(url, {responseType: 'text'})

同时，说明下angular请求好像只有调用.subscribe(）方法才可以执行，我这是请求是在service里面写的，在component里面调用的。 service:

getdataList(){ this.genanUrl ="http://localhost:4200/genan/api/MCU32/getDataCollect?jsonSql={sequence_id:'00022'}&limit=500&skip=0"; return this.http.get(this.genanUrl,{responseType: 'text'}); }

component:

getVersioninfo(){ console.log('getVersioninfo-----'); this.datainfoService.getDataCount().subscribe(result =>{ console.log('result111:' + result); })

切记不要将{responseType: ‘text’}放在请求头header或params中，它应该是单独的一项，否则无法生效。源码如下：

/** * Constructs a `GET` request that interprets the body as a text string * and returns the response as a string value. * * @param url The endpoint URL. * @param options The HTTP options to send with the request. * * @return An `Observable` of the response, with the response body of type string. */ get(url: string, options: { headers?: HttpHeaders | { [header: string]: string | string[]; }; observe?: 'body'; params?: HttpParams | { [param: string]: string | string[]; }; reportProgress?: boolean; responseType: 'text'; withCredentials?: boolean; }): Observable<string>;

Post请求：

处理大体相同，只是post请求参数有变化，中间请求body即使是空的也需要传，否则{responseType: ‘text’}就当成了请求body

return this.http.post(this.genanUrl,{},{responseType: 'text'});

源码如下：

/** * Constructs a `POST` request that interprets the body as a text string and * returns the response as a string value. * * @param url The endpoint URL. * @param body The content to replace with. * @param options HTTP options * * @return An `Observable` of the response, with a response body of type string. */ post(url: string, body: any | null, options: { headers?: HttpHeaders | { [header: string]: string | string[]; }; observe?: 'body'; params?: HttpParams | { [param: string]: string | string[]; }; reportProgress?: boolean; responseType: 'text'; withCredentials?: boolean; }): Observable<string>;

这里的请求返回的数据只是当成text文本处理，如果返回的数据还有其他形式，如：arraybuffer，blob格式处理方法相同，只是将text改成相应格式。下面提供部分源码如下，可以看到 responseType有四种：json，arraybuffer，blob，text

/** * Constructs a `PATCH` request that interprets the body as a JSON object * and returns the response in a given type. * * @param url The endpoint URL. * @param body The resources to edit. * @param options HTTP options. * * @return An `Observable` of the `HttpResponse` for the request, * with a response body in the given type. */ patch<T>(url: string, body: any | null, options?: { headers?: HttpHeaders | { [header: string]: string | string[]; }; observe?: 'body'; params?: HttpParams | { [param: string]: string | string[]; }; reportProgress?: boolean; responseType?: 'json'; withCredentials?: boolean; }): Observable<T>; /** * Constructs a `POST` request that interprets the body as an as an `ArrayBuffer` and returns * an `ArrayBuffer`. * * @param url The endpoint URL. * @param body The content to replace with. * @param options HTTP options. * * @return An `Observable` of the response, with the response body as an `ArrayBuffer`. */ post(url: string, body: any | null, options: { headers?: HttpHeaders | { [header: string]: string | string[]; }; observe?: 'body'; params?: HttpParams | { [param: string]: string | string[]; }; reportProgress?: boolean; responseType: 'arraybuffer'; withCredentials?: boolean; }): Observable<ArrayBuffer>; /** * Constructs a `POST` request that interprets the body as a `Blob` and returns the * response as a `Blob`. * * @param url The endpoint URL. * @param body The content to replace with. * @param options HTTP options * * @return An `Observable` of the response, with the response body as a `Blob`. */ post(url: string, body: any | null, options: { headers?: HttpHeaders | { [header: string]: string | string[]; }; observe?: 'body'; params?: HttpParams | { [param: string]: string | string[]; }; reportProgress?: boolean; responseType: 'blob'; withCredentials?: boolean; }): Observable<Blob>; /** * Constructs a `POST` request that interprets the body as a text string and * returns the response as a string value. * * @param url The endpoint URL. * @param body The content to replace with. * @param options HTTP options * * @return An `Observable` of the response, with a response body of type string. */ post(url: string, body: any | null, options: { headers?: HttpHeaders | { [header: string]: string | string[]; }; observe?: 'body'; params?: HttpParams | { [param: string]: string | string[]; }; reportProgress?: boolean; responseType: 'text'; withCredentials?: boolean; }): Observable<string>;