从服务器端（servlet）发送响应后如何在角度端获取属性

Question

@WebServlet("/findPerson")
public class FindPerson extends HttpServlet {
    // ... doGet implementation

    @Override
    protected void doPost( HttpServletRequest request, HttpServletResponse response )
            throws ServletException, IOException {

        // data to send to the client
        String name = "John White";
        int age = 54;



        // Adding attributes to the request
        request.setAttribute( "personName", name );
        request.setAttribute( "personAge", age );

        }
    }
}

调用后如何以角度获取这些属性“personName”和“personAge”的值

return  this.http.post('http://localhost:8080/findPerson',"");

Answer 1

this.http.post() 返回一个 observable。您需要订阅它才能获得响应

服务

findPerson(): Observable<any> {
  return this.http.post('http://localhost:8080/findPerson',"");
}

组件

name: any;
age: any;

this.someService.findPerson().subscribe(
  res => {
    this.name = res['personName'];
    this.age = res['personAge'];
    console.log(this.name); // <-- correct
    console.log(this.age); // <-- correct
  },
  error => {
    // always good practice to handle HTTP errors
  }

  console.log(this.name); // <-- wrong - would print `undefined`
  console.log(this.age); // <-- wrong - would print `undefined`
);

最需要注意的是调用是异步的。因此，任何直接依赖于响应的语句应该在订阅中。或者换句话说，您需要在需要响应的地方订阅。

您可以了解更多关于异步数据here。