編輯:關於Android編程
Android 網絡請求一般都涉及到圖片和JSON數據,怎樣快速的請求網絡JSON數據,解析JSON數據,並且一步生成自己想要的Java bean實體類?這個涉及到Android 開發效率的問題。由於接觸Android 網絡這方面比較多,自然就找到一些好的方法來快速開發Android 網絡模塊的相關內容,接下來就為大家揭曉 一步快速請求,解析JSON 數據生成對應的Java bean實體類的方法。
注:我們先把思路講解下吧:
1.網絡請求JSON數據代碼可以自己寫,當然我還是推薦使用網絡上開源的穩定的框架---Volley,相信很多人應該了解這個開源框架吧,不知道的百度去,這是一個很好用的網絡請求開源框架。
2.解析JSON 數據,最好的方法無疑是使用網絡上線程的工具 jar包(谷歌的GSON 阿裡的FastJson),我這裡選擇的是阿裡的FastJson,FastJson有優勢,具體優勢後面講解。
3.解析JSON數據後要將數據保存到 實體類中,我們需要自己定義實體類,但是,在使用FastJson 解析JSON數據的時候必須確保 JSON 數據字段和 實體類的成員變量名字相同,否則FastJson 是解析不出來的(Gson也解析不出來),但是使用FastJson 不區分實體類成員變量的大小寫,而Gson 區分,這就是為什麼我選擇FastJson解析JSON數據了。
一.我們需要解析JSON數據必然需要先定義 JSON數據信息實體類,然後才能解析JSON數據,將數據保存到類中。但是,定義這個類不需要一個變量的去敲代碼,而且有可能出錯。這裡我們拿中國天氣預報的一條JSON數據說明,http://www.weather.com.cn/data/cityinfo/101010100.html ,浏覽器請求後獲得的JSON數據是:
{
"weatherinfo": {
"city": "北京",
"cityid": "101010100",
"temp1": "5℃",
"temp2": "-3℃",
"weather": "晴",
"img1": "d0.gif",
"img2": "n0.gif",
"ptime": "11:00"
}
}那麼我們首先需要定義一個天氣信息類:
import java.util.HashMap;
import java.util.Map;
import javax.annotation.Generated;
import org.apache.commons.lang.builder.EqualsBuilder;
import org.apache.commons.lang.builder.HashCodeBuilder;
import org.apache.commons.lang.builder.ToStringBuilder;
@Generated("org.jsonschema2pojo")
public class Test {
private Weatherinfo weatherinfo;
private Map additionalProperties = new HashMap();
/**
*
* @return
* The weatherinfo
*/
public Weatherinfo getWeatherinfo() {
return weatherinfo;
}
/**
*
* @param weatherinfo
* The weatherinfo
*/
public void setWeatherinfo(Weatherinfo weatherinfo) {
this.weatherinfo = weatherinfo;
}
@Override
public String toString() {
return ToStringBuilder.reflectionToString(this);
}
public Map getAdditionalProperties() {
return this.additionalProperties;
}
public void setAdditionalProperty(String name, Object value) {
this.additionalProperties.put(name, value);
}
@Override
public int hashCode() {
return new HashCodeBuilder().append(weatherinfo).append(additionalProperties).toHashCode();
}
@Override
public boolean equals(Object other) {
if (other == this) {
return true;
}
if ((other instanceof Test) == false) {
return false;
}
Test rhs = ((Test) other);
return new EqualsBuilder().append(weatherinfo, rhs.weatherinfo).append(additionalProperties, rhs.additionalProperties).isEquals();
}
} import java.util.HashMap;
import java.util.Map;
import javax.annotation.Generated;
import org.apache.commons.lang.builder.EqualsBuilder;
import org.apache.commons.lang.builder.HashCodeBuilder;
import org.apache.commons.lang.builder.ToStringBuilder;
@Generated("org.jsonschema2pojo")
public class Weatherinfo {
private String city;
private String cityid;
private String temp1;
private String temp2;
private String weather;
private String img1;
private String img2;
private String ptime;
private Map additionalProperties = new HashMap();
/**
*
* @return
* The city
*/
public String getCity() {
return city;
}
/**
*
* @param city
* The city
*/
public void setCity(String city) {
this.city = city;
}
/**
*
* @return
* The cityid
*/
public String getCityid() {
return cityid;
}
/**
*
* @param cityid
* The cityid
*/
public void setCityid(String cityid) {
this.cityid = cityid;
}
/**
*
* @return
* The temp1
*/
public String getTemp1() {
return temp1;
}
/**
*
* @param temp1
* The temp1
*/
public void setTemp1(String temp1) {
this.temp1 = temp1;
}
/**
*
* @return
* The temp2
*/
public String getTemp2() {
return temp2;
}
/**
*
* @param temp2
* The temp2
*/
public void setTemp2(String temp2) {
this.temp2 = temp2;
}
/**
*
* @return
* The weather
*/
public String getWeather() {
return weather;
}
/**
*
* @param weather
* The weather
*/
public void setWeather(String weather) {
this.weather = weather;
}
/**
*
* @return
* The img1
*/
public String getImg1() {
return img1;
}
/**
*
* @param img1
* The img1
*/
public void setImg1(String img1) {
this.img1 = img1;
}
/**
*
* @return
* The img2
*/
public String getImg2() {
return img2;
}
/**
*
* @param img2
* The img2
*/
public void setImg2(String img2) {
this.img2 = img2;
}
/**
*
* @return
* The ptime
*/
public String getPtime() {
return ptime;
}
/**
*
* @param ptime
* The ptime
*/
public void setPtime(String ptime) {
this.ptime = ptime;
}
@Override
public String toString() {
return ToStringBuilder.reflectionToString(this);
}
public Map getAdditionalProperties() {
return this.additionalProperties;
}
public void setAdditionalProperty(String name, Object value) {
this.additionalProperties.put(name, value);
}
@Override
public int hashCode() {
return new HashCodeBuilder().append(city).append(cityid).append(temp1).append(temp2).append(weather).append(img1).append(img2).append(ptime).append(additionalProperties).toHashCode();
}
@Override
public boolean equals(Object other) {
if (other == this) {
return true;
}
if ((other instanceof Weatherinfo) == false) {
return false;
}
Weatherinfo rhs = ((Weatherinfo) other);
return new EqualsBuilder().append(city, rhs.city).append(cityid, rhs.cityid).append(temp1, rhs.temp1).append(temp2, rhs.temp2).append(weather, rhs.weather).append(img1, rhs.img1).append(img2, rhs.img2).append(ptime, rhs.ptime).append(additionalProperties, rhs.additionalProperties).isEquals();
}
} 二.網絡請求Json 數據,大家知道,在Android 中寫一個簡單的網絡請求任務都需要寫 很長一段代碼,並且還需要注意android 網絡請求必須在子線程中處理,所以跟新UI就得注意了。這裡我們使用2013年谷歌大會上提供的開源框架 Volley ,使用這個框架請求網絡非常方便,不了解的請看博客:Android Volley完全解析(一),初識Volley的基本用法
因為我們這一節重點是一步解析JSON數據獲得 Java bean,所以我自己仿照 Volley 的StringRequest 重新自定義了一個FastJosnRequest 類來使用,使用這個類可以直接獲得Java bean實體類,都不需要你自己解析JSON數據了,給你省了很多事情。
FastJson jar包下載鏈接:http://download.csdn.net/detail/feidu804677682/8341467
FastJosnRequest類的實現如下:
/* * Copyright (C) 2011 The Android Open Source Project Licensed under the Apache * License, Version 2.0 (the "License"); you may not use this file except in * compliance with the License. You may obtain a copy of the License at * http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law * or agreed to in writing, software distributed under the License is * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY * KIND, either express or implied. See the License for the specific language * governing permissions and limitations under the License. */ package com.android.volley.toolbox; import com.alibaba.fastjson.JSON; import com.android.volley.AuthFailureError; import com.android.volley.NetworkResponse; import com.android.volley.ParseError; import com.android.volley.Request; import com.android.volley.Response; import com.android.volley.Response.ErrorListener; import com.android.volley.Response.Listener; import java.io.UnsupportedEncodingException; import java.util.Collections; import java.util.Map; /** * A canned request for retrieving the response body at a given URL as a String. * * @param這裡我直接使用了FastJson jar包來幫助完成解析JSON數據,直接返回給用戶實體類,而不許要用戶去解析JSON數據。研究過Volley 開源框架的人會發現,我這個類中重寫了幾個方法,getParams()和getHeaders()兩個方法。因為我需要兼容來自用戶不同方式的請求(GET和POST)。當使用GET請求的時候 params 和headers 傳值 null 進來即可。*/ public class FastJsonRequest extends Request { private final Listener mListener; private final Map mParams; private Map mHeaders; private Class mClass; /** * Creates a new request with the given method. * * @param method * the request {@link Method} to use * @param url * URL to fetch the string at * @param params * Params for the POST request. * @param headers * Headers for the POST request. * @param listener * Listener to receive the String response * @param errorListener * Error listener, or null to ignore errors */ public FastJsonRequest(int method, String url, Map params, Map headers, Class mClass, Listener listener, ErrorListener errorListener) { super(method, url, errorListener); mListener = listener; mParams = params; mHeaders = headers; this.mClass = mClass; } /** * Creates a new GET or POST request, if request params is null the request * is GET otherwise POST request. * * @param url * URL to fetch the string at * @param params * Params for the POST request. * @param headers * Headers for the POST request. * @param listener * Listener to receive the String response * @param errorListener * Error listener, or null to ignore errors */ public FastJsonRequest(String url, Map params, Map headers, Class mClass, Listener listener, ErrorListener errorListener) { this(null == params ? Method.GET : Method.POST, url, params, headers, mClass, listener, errorListener); } @Override protected Map getParams() throws AuthFailureError { return mParams; } @Override public Map getHeaders() throws AuthFailureError { if (null == mHeaders) { mHeaders = Collections.emptyMap(); } return mHeaders; } @Override protected void deliverResponse(T response) { mListener.onResponse(response); } @Override protected Response parseNetworkResponse(NetworkResponse response) { try { String jsonString = new String(response.data, HttpHeaderParser.parseCharset(response.headers)); return Response.success(JSON.parseObject(jsonString, mClass), HttpHeaderParser.parseCacheHeaders(response)); } catch (UnsupportedEncodingException e) { return Response.error(new ParseError(e)); } } }
三. 接口的使用如下:
package com.example.fastjson;
import java.util.List;
import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONObject;
import com.android.volley.RequestQueue;
import com.android.volley.Response.ErrorListener;
import com.android.volley.Response.Listener;
import com.android.volley.VolleyError;
import com.android.volley.VolleyLog;
import com.android.volley.toolbox.FastJsonRequest;
import com.android.volley.toolbox.StringRequest;
import com.android.volley.toolbox.Volley;
import com.example.fastjson.bean.Apk;
import com.example.fastjson.bean.App;
import android.os.Bundle;
import android.app.Activity;
import android.util.Log;
import android.view.Menu;
public class MainActivity extends Activity {
String url = "http://www.weather.com.cn/data/cityinfo/101010100.html";
RequestQueue mQueue;
String TAG = "MainActivity";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mQueue = Volley.newRequestQueue(this);
mQueue = Volley.newRequestQueue(this);
FastJsonRequest fRequest = new FastJsonRequest(url, null,
null, Test.class, new Listener() {
@Override
public void onResponse(Test response) {
Log.i(TAG, response.getWeatherinfo().toString());
}
}, new ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
}
});
mQueue.add(fRequest);
}
}
Weatherinfo [city=北京, cityId=101010100, temp1=5℃, temp2=-3℃, weather=晴, img1=d0.gif, img2=n0.gif, ptime=11:00]
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