使用Angular2'POST'的Web服务休息

Question

这是我的Service Typscript，我有Json post

方法

 import {Injectable, Inject} from "angular2/core";
    import {Http, Headers} from "angular2/http";
    import 'rxjs/add/operator/map';
    import {User} from "../User/User";


    @Injectable()
    export class loginService {

        constructor(@Inject(Http) private _http:Http) {
        }
        enter code here

        postJSON(){
            var json = JSON.stringify({v:"value",a:"3"}); // var creds = "username=" + "khalil" + "&password=" + 3;   .map(res=>res.text());
            var headers = new Headers();
            headers.append('Content-Type','application/json');
            return this._http.post('http://localhost:8080/connect',json,{
                    headers:headers
                })
                .map(res=>res.json());

        }

这是我订阅的组件

import {Component, Inject} from 'angular2/core';
import {Router} from "angular2/router";
import {loginService} from "./login.service";
import {HTTP_PROVIDERS, Http} from "angular2/http";
import {User} from "../User/User";


@Component({
    selector: 'login',
    templateUrl: '../dev/login/login.html',
    providers: [HTTP_PROVIDERS, loginService]
})

export class TestComponent {

    getData:string;

    postData:string;

    constructor(private _router:Router,
                @Inject(Http) http:Http,
                private _loginService:loginService) {


    }


    postJson(){
        this._loginService.postJSON().subscribe(
            data => this.postData = JSON.stringify(data),
            error => alert(this.postData + error),
            () => console.log("finished")
        );
    }
}        
        }

服务器端我使用spring 4

这是我的控制器

@RestController
@CrossOrigin()
public class HomeController {


    @RequestMapping(value = "/connect", method = RequestMethod.POST,produces = MediaType.APPLICATION_JSON_VALUE)
    public @ResponseBody String connect(String v, String a) {
        int i = Integer.parseInt(a);
        if (v.equals("khalil") && i == 3) {
            System.out.println("----------------------***********************---------------------");
        } else {
            System.out.println("----------------------**** elseeeeee *******************---------------------");

        }
        return v+a;

    }
}

当我尝试调用Web服务时，我收到此错误

 POST http://localhost:8080/connect 500 (Internal Server Error)(anonymous function)
 @ http.js:683Observable.subscribe 
@ Rx.js:11006Observable._subscribe
 @ Rx.js:11038Observable.subscribe 
@ Rx.js:11004loginComponent.postJson
 @ login.component.ts:63ChangeDetector_loginComponent_0.handleEventInternal 
@ viewFactory_loginComponent:415AbstractChangeDetector.handleEvent
 @ angular2.js:9568AppView.triggerEventHandlers
 @ angular2.js:10246(anonymous function)
 @ viewFactory_loginComponent:558(anonymous function)
 @ angular2.js:14068(anonymous function)
 @ angular2.js:13496ZoneDelegate.invoke 
@ angular2-polyfills.js:332NgZoneImpl.inner.inner.fork.onInvoke 
@ angular2.js:2111ZoneDelegate.invoke
 @ angular2-polyfills.js:331Zone.runGuarded 
@ angular2-polyfills.js:241NgZoneImpl.runInner
 @ angular2.js:2140NgZone.run
 @ angular2.js:13649outsideHandler 
@ angular2.js:13495ZoneDelegate.invokeTask
 @ angular2-polyfills.js:365Zone.runTask
 @ angular2-polyfills.js:263ZoneTask.invoke 
@ angular2-polyfills.js:431

感谢帮助我^^