null天气预报是什么意思准_null天气预报

1.ja.lang.NullPointerException 哪位高手帮帮忙

百度API Key申请地址：://lbsyun.baidu/apiconsole/key

创建应用 如图：?

提交后得到API Key 如图：?

接口实例：://api.map.baidu/telematics/v3/weather？location=南昌&output=json&ak=你的API Key&mcode=你的数字签名SHA1;com.example.administrator.jsontest（包名）

接口参数说明

参数类型

参数名称

是否必须

具体描述

String location true 输入城市名或经纬度，城市名如北京或者131，经纬度格式为lng，lat坐标，如：location=116.305145,39.982368;全国值为all，返回省会城市自治区，港澳台天气情况多城市天气预报中间用“|”分隔，如：location=116.305145,39.982368|123.342323,36238945|...

String output false 输出的数据格式，默认为xml格式，当output设置为json时，输出的为json数据格式

String coord_type false 请求参数坐标类型，默认为gcj02经纬度坐标。允许的值为bd09ll、bd09mc、gcj02、wgs84；

返回的JSON数据

{

"error":0,

"status":"success",

"date":"2016-03-05",

"results":[

{

"currentCity":"北京",

"pm25":"144",

"index":[

{

"title":"穿衣",

"zs":"较冷",

"tipt":"穿衣指数",

"des":"建议着厚外套加毛衣等服装。年老体弱者宜着大衣、呢外套加羊毛衫。"},

{

"title":"洗车",

"zs":"不宜",

"tipt":"洗车指数",

"des":"不宜洗车，未来24小时内有扬沙或浮尘，如果在此期间洗车，极易很快蒙上新的灰尘。"},

{

"title":"旅游",

"zs":"一般",

"tipt":"旅游指数",

"des":"风稍大，扬沙或浮尘天气对能见度和空气质量都会有些影响，出行请注意交通安全和取适当的防尘措施。"},

{

"title":"感冒",

"zs":"易发",

"tipt":"感冒指数",

"des":"昼夜温差大，风力较强，易发生感冒，请注意适当增减衣服，加强自我防护避免感冒。"},

{

"title":"运动",

"zs":"较不宜",

"tipt":"运动指数",

"des":"有扬沙或浮尘，建议适当停止户外运动，选择在室内进行运动，以避免吸入更多沙尘，有损健康。"},

{

"title":"紫外线强度",

"zs":"最弱",

"tipt":"紫外线强度指数",

"des":"属弱紫外线辐射天气，无需特别防护。若长期在户外，建议涂擦SPF在8-12之间的防晒护肤品。"}

? ],

?"weather_data":[

?{

?"date":"周六 03月05日 (实时：12℃)", ?"dayPictureUrl":"://api.map.baidu/images/weather/day/fuchen.png",

"nightPictureUrl":"://api.map.baidu/images/weather/night/qing.png",

?"weather":"浮尘转晴",

?"wind":"北风4-5级",

?"temperature":"12 ~ -1℃"},

?{

?"date":"周日",

"dayPictureUrl":"://api.map.baidu/images/weather/day/duoyun.png",

"nightPictureUrl":"://api.map.baidu/images/weather/night/duoyun.png",

?"weather":"多云",

?"wind":"微风",

?"temperature":"10 ~ -3℃"},

?{

?"date":"周一", "dayPictureUrl":"://api.map.baidu/images/weather/day/duoyun.png",

"nightPictureUrl":"://api.map.baidu/images/weather/night/yin.png",

?"weather":"多云转阴",

?"wind":"微风",

?"temperature":"13 ~ 2℃"},

?{

?"date":"周二", "dayPictureUrl":"://api.map.baidu/images/weather/day/yin.png",

"nightPictureUrl":"://api.map.baidu/images/weather/night/duoyun.png",

?"weather":"阴转多云",

?"wind":"北风3-4级",

?"temperature":"6 ~ -1℃"}

?]}]}

3. ?我们来写个demo，代码如下：

package com.example.administrator.jsontest;

public class MainActivity extends Activity {

private Button button;

private TextView textView;

private Handler handler = new Handler() {

@Override

public void handleMessage(Message msg) {

switch (msg.what) {

case 0:

String re = (String) msg.obj;

textView.setText(re);

break;

}

}

};

@Override

protected void onCreate(Bundle sedInstanceState) {

super.onCreate(sedInstanceState);

setContentView(R.layout.activity_main);

button = (Button) findViewById(R.id.button);

textView = (TextView) findViewById(R.id.textView);

button.setOnClickListener(new View.OnClickListener() {

@Override

public void onClick(View v) {

Log.i("T", "点击了Button");

sendRequestWithHttpClient();

}

});

}

private void sendRequestWithHttpClient() {

new Thread(new Runnable() {

@Override

public void run() {

HttpURLConnection connection = null;

try {

URL url = new URL("://api.map.baidu/telematics/v3/weather?location=南昌&output=json&ak=8ixCCFzlBB617YX7tONI2P5B&mcode=1C:6B:42:33:E8:A6:DC:A2:11:6E:26:EC:84:BD:42:E3:8E:6B:57:9A;com.example.administrator.jsontest");

connection = (HttpURLConnection) url.openConnection();

connection.setRequestMethod("GET");

connection.setConnectTimeout(5000);

connection.setReadTimeout(5000);

InputStream in = connection.getInputStream();

BufferedReader reader = new BufferedReader(new InputStreamReader(in));

StringBuilder response = new StringBuilder();

String line;

while ((line = reader.readLine()) != null) {

response.end(line);

}

Log.i("T", response.toString()); parseJSONObjectOrJSONArray(response.toString());

} catch (MalformedURLException e) {

e.printStackTrace();

} catch (IOException e) {

e.printStackTrace();

}

}

}).start();

}

//解析JSON数据

private void parseJSONObjectOrJSONArray(String jsonData) {

try {

String count = "";

JSONObject jsonObject = new JSONObject(jsonData);

JSONArray jsonArray = jsonObject.getJSONArray("results");

if (jsonArray.length() > 0) {

JSONObject object = jsonArray.getJSONObject(0);

String city = object.optString("currentCity");

JSONArray array = object.getJSONArray("weather_data");

for (int i = 0; i < array.length(); i++) {

JSONObject jsonObject1 = array.getJSONObject(i);

String dateDay = jsonObject1.optString("date");

String weather = jsonObject1.optString("weather");

String wind = jsonObject1.optString("wind");

String temperature = jsonObject1.optString("temperature");

count =count +"\n"+ dateDay + " " + weather + " " + wind + " " + temperature;

Log.i("AAA",count);

}

Message message = new Message();

message.what = 0;

message.obj = count;

handler.sendMessage(message);

}

} catch (JSONException e) {

e.printStackTrace();

}

}

}

4.?运行结果如下：?

ja.lang.NullPointerException 哪位高手帮帮忙

平昌天气预报 (2011-02-27 18:00发布) 关闭未来4-7天天气预报 天气图例 日期天气现象气温风向风力 28日星期一白天小雨高温 12℃ 东风 微风 夜间阴低温 9℃ 东风 微风 1日星期二白天多云高温 15℃ 东风 微风 夜间阴低温 9℃ 东风 微风 2日星期三白天小雨高温 12℃ 东风 微风 夜间阴低温 8℃ 东风 微风 未来4-7天天气预报（2011-02-27 18:00发布） 仅供参考 3日星期四白天阴高温 12℃ 东风 微风 夜间阴低温 8℃ 东风 微风 4日星期五白天阴高温 12℃ 东风 微风 夜间阴低温 9℃ 东风 微风 5日星期六白天小雨高温 13℃ 东风 微风 夜间阴低温 10℃ 东风 微风

大概看了一下

// 提取天气预报主体

Pattern pt_body = Patternpile("<table border='1' width='520' align='center' cellpadding='1' cellspacing='1'>(.*)</table></tr>"， Pattern.MULTILINE | Pattern.DOTALL);

mc = pt_body.matcher(str);

String body = null;

while (mc.find()) {

body = mc.group(1).trim();

}

// 提取天气预报条目

Pattern pt_item = Patternpile(

"<tr bgcolor='#DEF3FF'>(.*)</td></tr>", Pattern.MULTILINE

| Pattern.DOTALL);

mc = pt_item.matcher(body);

是这mc = pt_item.matcher(body);空指针，因为前面根本没匹配上，所以body还是null.