要访问完整的响应（不仅仅是响应的主体），您必须传递 observe：'响应您的http请求中的'参数选项。现在，您可以使用 res.headers访问标题

To access the full response (not just the body of the response), you must pass the observe: 'response' parameter option in your http request. Now you can access the headers with res.headers

return this.http.post('http://127.0.0.1:8080/api/v1/login', {
        'username': username,
        'password': password
    }, {
        headers: new HttpHeaders()
            .set('Content-Type', 'application/json'),
        observe: 'response'
    })
    .map(res => {
        let myHeader = res.headers.get('my-header');
    });

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