之前的json轉對象，對象轉json?？偸潜容^繁瑣，不夠簡潔。自從接觸到jackson之后，發現原來對象和json轉換可以這么簡單。拿一個天氣預報的小例子來說明一下~如下圖?！救羰怯行≌`，還望指正】
不說，直接上碼~
首先，在pom.xml里弄好依賴
具體依賴需要上網去查找，咱用的是下面這個。
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<!-- 對象轉換成json引入如下依賴 --><!-- 文檔：https://www.yiibai.com/jackson/jackson_first_application.html#article-start --><dependency> <groupId>com.fasterxml.jackson.core</groupId> <artifactId>jackson-databind</artifactId> <version>2.7.4</version></dependency> |
然后嘞，準備一個接口，
用來獲取天氣預報接口的數據
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package com.lvfeng.tool.weather; import java.io.ByteArrayOutputStream;import java.io.InputStream;import java.net.URL; /** * @author LvFeng * 來源：https://www.nowapi.com/ * 文檔：https://www.nowapi.com/api/weather.future * 接口服務器【請求頭】：https://sapi.k780.com http://api.k780.com * 每三個月一更新，需要定期更新 */public class WeatherAPI { /* * 00a.天氣預報接口 */ public static final String APP_KEY_WEATHER = "你自己的key"; //KEY public static final String SIGN_WEATHER = "你自己的sign"; //SIGN /* * 001.獲取一周的天氣 * @param 請求城市氣象編碼，請求APPKey，SignKey，返回數據格式 * @return JSON * DOC:https://www.nowapi.com/api/weather.future * FORMAT:http://api.k780.com/?app=weather.future&weaid=1&appkey=APPKEY&sign=SIGN&format=json */ public static String getWeatherWeek(String cityNumber,String ak,String sg,String returnFormat) throws Exception{ String str = "http://api.k780.com/?app=weather.future&weaid="+cityNumber+"&appkey="+ak+"&sign="+sg+"&format="+returnFormat; URL url = new URL(str); //請求URL InputStream ins = url.openStream(); //打開輸入流 ByteArrayOutputStream out=new ByteArrayOutputStream(); try { byte buf[] = new byte[1024]; int read = 0; while ((read = ins.read(buf)) > 0) { out.write(buf, 0, read); } } finally { if (ins != null) { ins.close(); } } byte b[] = out.toByteArray( ); return new String(b,"utf-8"); //轉碼 }} |
插一嘴，簡單粗暴的講，[]就是數組，{}就是對象，我們測試接口過后，
返回的json字符串就像下面這個樣子
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/* { * "success":"1", * "result":[{ * "weaid":"1", * "days":"2018-07-18", * "week":"星期三", * "cityno":"beijing", * "citynm":"北京", * "cityid":"101010100", * "temperature":"32℃/25℃", * "humidity":"0%/0%", * "weather":"多云轉小雨", * "weather_icon":"http://api.k780.com/upload/weather/d/1.gif", * "weather_icon1":"http://api.k780.com/upload/weather/n/7.gif", * "wind":"東風", * "winp":"<3級", * "temp_high":"32", * "temp_low":"25", * "humi_high":"0", * "humi_low":"0", * "weatid":"2", * "weatid1":"8", * "windid":"10", * "winpid":"395", * "weather_iconid":"1", * "weather_iconid1":"7" * }, 這后面類似…… */ |
然后我們根據這構建對象，根據這段json分析，這可能是倆對象，然后，一個對象是結果集數組[]，一個對象是狀態（是否成功），于是，
我拆成了下面兩個對象
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package com.lvfeng.tool.weather.pojo; import java.util.List;import com.fasterxml.jackson.annotation.JsonIdentityInfo;import com.fasterxml.jackson.annotation.ObjectIdGenerators; /** * @author Administrator * 一周天氣對象 * DOC:https://blog.csdn.net/u010457406/article/details/50921632 * https://blog.csdn.net/jxchallenger/article/details/79293772 */@JsonIdentityInfo(generator = ObjectIdGenerators.PropertyGenerator.class,property ="success")public class WeatherWeek { private String success; //是否成功 private List<Result> result; //結果集數組 public String getSuccess() { return success; } public void setSuccess(String success) { this.success = success; } public List<Result> getResult() { return result; } public void setResult(List<Result> result) { this.result = result; }} |
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package com.lvfeng.tool.weather.pojo;/** * @author LvLvFeng * Weather子類，天氣結果的返回值 */public class Result { private String weaid; //本站【調用接口的這個站點】的城市ID編號 private String days; //日期 private String week; //周幾 private String cityno; //城市編碼 private String citynm; //城市名稱 private String cityid; //城市氣象ID【標準】 private String temperature; //氣溫 private String humidity; //濕度【暫未使用】 private String weather; //天氣 private String weather_icon; //白天的氣象圖標 private String weather_icon1; //夜間的氣象圖標 private String wind; //風向 private String winp; //風力 private String temp_high; //最高氣溫 private String temp_low; //最低氣溫 private String humi_high; //溫度欄位【棄用】 private String humi_low; //濕度欄位【棄用】 private String weatid; //白天天氣ID，可對照weather.wtype接口中weaid private String weatid1; //夜間天氣ID，可對照weather.wtype接口中weaid private String windid; //風向ID(暫無對照表) private String winpid; //風力ID(暫無對照表) private String weather_iconid; //氣象圖標編號(白天),對應weather_icon 1.gif private String weather_iconid1; //氣象圖標編號(夜間),對應weather_icon1 0.gif public String getWeaid() { return weaid; } public void setWeaid(String weaid) { this.weaid = weaid; } public String getDays() { return days; } public void setDays(String days) { this.days = days; } public String getWeek() { return week; } public void setWeek(String week) { this.week = week; } public String getCityno() { return cityno; } public void setCityno(String cityno) { this.cityno = cityno; } public String getCitynm() { return citynm; } public void setCitynm(String citynm) { this.citynm = citynm; } public String getCityid() { return cityid; } public void setCityid(String cityid) { this.cityid = cityid; } public String getTemperature() { return temperature; } public void setTemperature(String temperature) { this.temperature = temperature; } public String getHumidity() { return humidity; } public void setHumidity(String humidity) { this.humidity = humidity; } public String getWeather() { return weather; } public void setWeather(String weather) { this.weather = weather; } public String getWeather_icon() { return weather_icon; } public void setWeather_icon(String weather_icon) { this.weather_icon = weather_icon; } public String getWeather_icon1() { return weather_icon1; } public void setWeather_icon1(String weather_icon1) { this.weather_icon1 = weather_icon1; } public String getWind() { return wind; } public void setWind(String wind) { this.wind = wind; } public String getWinp() { return winp; } public void setWinp(String winp) { this.winp = winp; } public String getTemp_high() { return temp_high; } public void setTemp_high(String temp_high) { this.temp_high = temp_high; } public String getTemp_low() { return temp_low; } public void setTemp_low(String temp_low) { this.temp_low = temp_low; } public String getHumi_high() { return humi_high; } public void setHumi_high(String humi_high) { this.humi_high = humi_high; } public String getHumi_low() { return humi_low; } public void setHumi_low(String humi_low) { this.humi_low = humi_low; } public String getWeatid() { return weatid; } public void setWeatid(String weatid) { this.weatid = weatid; } public String getWeatid1() { return weatid1; } public void setWeatid1(String weatid1) { this.weatid1 = weatid1; } public String getWindid() { return windid; } public void setWindid(String windid) { this.windid = windid; } public String getWinpid() { return winpid; } public void setWinpid(String winpid) { this.winpid = winpid; } public String getWeather_iconid() { return weather_iconid; } public void setWeather_iconid(String weather_iconid) { this.weather_iconid = weather_iconid; } public String getWeather_iconid1() { return weather_iconid1; } public void setWeather_iconid1(String weather_iconid1) { this.weather_iconid1 = weather_iconid1; } } |
開始書寫工具類，方便以后調用~
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package com.lvfeng.tool.change; import java.io.IOException;import com.fasterxml.jackson.core.JsonParseException;import com.fasterxml.jackson.core.JsonProcessingException;import com.fasterxml.jackson.databind.JsonMappingException;import com.fasterxml.jackson.databind.ObjectMapper; /** * @author LvLvFeng * 操作json的封裝方法 * use:jackson */public class JSONChange { /* * 001.json轉換成對象 * @param:傳入對象，json字符串 * @return:Object */ public static Object jsonToObj(Object obj,String jsonStr) throws JsonParseException, JsonMappingException, IOException { ObjectMapper mapper = new ObjectMapper(); return obj = mapper.readValue(jsonStr, obj.getClass()); } /* * 002.對象轉換成json * @param:傳入對象 * @return:json字符串 */ public static String objToJson(Object obj) throws JsonProcessingException { ObjectMapper mapper = new ObjectMapper(); return mapper.writeValueAsString(obj); }} |
封裝完成，寫測試類
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package com.lvfeng.tool.weather; import com.lvfeng.tool.change.JSONChange;import com.lvfeng.tool.weather.pojo.WeatherWeek; public class TestWeather { public static void main(String[] args) throws Exception{ //城市列表，ak,sg,返回格式 String res = WeatherAPI.getWeatherWeek("1", WeatherAPI.APP_KEY_WEATHER, WeatherAPI.SIGN_WEATHER, "json"); System.out.println("結果集" + res); String res2 = WeatherAPI.getNowWeather("1", WeatherAPI.APP_KEY_WEATHER, WeatherAPI.SIGN_WEATHER, "json"); System.out.println("結果集2" + res2); WeatherWeek wea = (WeatherWeek)JSONChange.jsonToObj(new WeatherWeek(), res); System.out.println("是否成功？"+wea.getSuccess()+"結果集舉例【城市名稱】："+wea.getResult().get(0).getCitynm()); System.out.println("---------------------開始反轉------------------"); String jsonStr = JSONChange.objToJson(wea); System.out.println("反轉結果："+jsonStr); }} |
如上，就把查詢天氣預報的結果轉換成倆對象了，然后我們操作對象~啦啦啦！
以上為個人經驗，希望能給大家一個參考，也希望大家多多支持服務器之家。
原文鏈接：https://blog.csdn.net/qq_37525899/article/details/81132069
