Ionic HttpClient：JSONObject 文本必须以 '{' 在 1 [字符 2 第 1 行] 开头答案

【问题标题】：Ionic HttpClient: A JSONObject text must begin with '{' at 1 [character 2 line 1]Ionic HttpClient：JSONObject 文本必须以 '{' 在 1 [字符 2 第 1 行] 开头
【发布时间】：2019-01-18 11:25:19
【问题描述】：

我有一个使用 org.json 的 Java REST API，其中我有一个方法 putJson() 可以解析传入的 JSON 数据并将其保存到数据库表中。

import javax.ws.rs.core.Context;
import javax.ws.rs.core.UriInfo;
import javax.ws.rs.Produces;
import javax.ws.rs.Consumes;
import javax.ws.rs.Path;
import javax.ws.rs.PUT;
import javax.ws.rs.PathParam;
import javax.ws.rs.core.MediaType;
import org.json.JSONArray;
import org.json.JSONObject;

@Path("consumptions")
public class ConsumptionsResource extends Database {

    @Context
    private UriInfo context;

    public ConsumptionsResource() {
        this.openConnection();
    }

    @PUT
    @Path("{id}")
    @Consumes(MediaType.APPLICATION_JSON)
    public boolean putJson(@PathParam("id") String id, String content) {
        boolean ok = true;
        JSONObject json = new JSONObject(content);
        String date = json.getString("pvm");
        String time = json.getString("klo");
        String consumption = json.getString("kulutus");

        try {
            String sql = "UPDATE kulutus SET pvm = ?, klo = ?, kulutus = ? WHERE id = ?";
            this.preparedstatement = yhteys.prepareStatement(sql);
            this.preparedstatement.setString(1, pvm);
            this.preparedstatement.setString(2, klo);
            this.preparedstatement.setString(3, kulutus);
            this.preparedstatement.setString(4, String.valueOf(id));
            this.preparedstatement.execute();
            this.closeConnection();
        } catch (Exception e) {
            e.printStackTrace();
            ok = false;
        }
        return ok;
    }
}

我还有一个 Ionic 3 应用程序，它使用 PUT 方法和 JSON 数据连接到这个 API。 counter.ts：

import { Component } from '@angular/core';
import { IonicPage, NavController, NavParams } from 'ionic-angular';
import { KulutusProvider } from '../../providers/consumption/consumption';
import { consumption } from '../../app/consumption.interface';

@IonicPage()
@Component({
  selector: 'page-counter',
  templateUrl: 'counter.html',
})
export class CounterPage {

  date: string = new Date().toLocaleDateString();
  last_smoked: string;
  counter: number = 0;
  data = {} as consumption;

  constructor(public navCtrl: NavController, 
    public navParams: NavParams,
    public kulutusProvider: KulutusProvider
    ) {
  }

  ionViewDidLoad() {
    let current_day = this.yyyy_mm_dd();
    this.consumptionProvider.getConsumption(current_day).then((data) => {
      this.data = data[0];
    }, (error) => {
      this.data = error;
    });
  }

  addOne = () :void => {
    this.data.consumption += 1;
    this.consumptionProvider.setConsumption(this.data).then((value) => {
      console.log(value);
    });
  }

  yyyy_mm_dd = () :string => {
    let year = new Date().getFullYear();
    let month = `0${new Date().getMonth()+1}`;
    let day = new Date().getDate();
    return `${year}-${month}-${day}`;
  }

}

这里是提供者的consumer.ts：

import { HttpClient } from '@angular/common/http';
import { Injectable } from '@angular/core';
import { Storage } from '@ionic/storage';
import { pack } from '../../app/aski.interface';
import { consumption } from '../../app/kulutus.interface';

@Injectable()
export class ConsumptionProvider {

  constructor(public http: HttpClient, public storage: Storage) { }

  setPack(pack: pack) {
    this.storage.set("pack_info", pack);
  }

  getConsumption(date: string) {
    return new Promise((resolve, reject) => {
      this.http.get(`http://localhost:8080/savukelaskuri/webresources/consumptions/${pvm}`)
        .subscribe((data) => {
          resolve(data);
        }, (error) => {
          reject(error);
        })
    })
  }

  setConsumption(data: consumption) {
    return new Promise((resolve, reject) => {
      this.http.put(`http://localhost:8080/savukelaskuri/webresources/kulutukset/${data.date}`, data[0])
        .subscribe((data) => {
          resolve(data);
        }, (error) => {
          reject(error);
        });
    })
  }

}

我希望能够解析 JSON 数据，然后将其保存到数据库中，但我收到此错误 org.json.JSONException: A JSONObject text must begin with '{' at 1 [character 2 line 1]。

【问题讨论】：

标签： ionic3 jax-rs org.json

【解决方案1】：

setConsumption() 只需将 data 作为 PUT 正文，而不是 data[0]。

setConsumption(data: consumption) {
    return new Promise((resolve, reject) => {
      this.http.put(`http://localhost:8080/savukelaskuri/webresources/kulutukset/${data.date}`, data)
        .subscribe((data) => {
          resolve(data);
        }, (error) => {
          reject(error);
        });
    })
  }

在 ConsummptionResource 类 putJson() 上而不是字符串类型

String consumption = json.getString("kulutus");

consumption 需要为整数

int consumption = json.getint("kulutus");

【讨论】：