Question

如何迭代String of String，String的集合。

我有一个pojo类

        public class GPObject_PublicUser  {

    private String kind;
    private String id;
    private String displayName;
    private String objectType;
    private String gender;
    private String aboutMe;
    private String url;


    private Map<String,String> image;

    private Collection<Map<String,String>> placesLived;



}

现在我将String转换为gson并尝试将数据映射到pojo类。

         Gson gson = new Gson();
          GPObject_PublicUser hello  =gson.fromJson( jsonText, GPObject_PublicUser.class );

示例json text：

     { "kind": "plus#person", "etag": "\"goGJzLGpDAdTIjyZUs7et8jwqfg/dSQkZzjp1Ufk7Fq69sg0cCLCwLY\"", "occupation": "Global News Broadcaster", "gender": "other", "urls": [  {   "value": "http://twitter.com/cctv_america",   "type": "otherProfile",   "label": "CCTV_America"  },  {   "value": "https://www.facebook.com/CCTVAmerica",   "type": "otherProfile",   "label": "Facebook"  },  {   "value": "http://www.cctv-america.com",   "type": "contributor",   "label": "CCTV-America.com"  },  {   "value": "http://www.cctv-america.com",   "type": "other",   "label": "Official Website"  } ], "objectType": "person", "id": "105608978310637089588", "displayName": "CCTV America", "name": {  "familyName": "America",  "givenName": "CCTV" }, "tagline": "CCTV America contributes programming from Washington DC to CCTV News, the 24-hour English-language news channel of China Central Television", "aboutMe": "\u003cdiv\u003eCCTV America launched from Washington on Monday, February 6th 2012. Â It currently produces five hours of weekday programming seen on the North American east coast in the early evening hours. Â Programs include numerous daily news broadcasts as well as BIZ ASIA AMERICA, focusing on global economic trends, trade and investment.\u003c/div\u003e\u003cdiv\u003eâ€œThe Heat,â€? weekdays at 7pm EST provides talk-and-debate on a range of topical issues. &#39;Americas Now&#39; on Sunday nights provides in depth magazine coverage on Central and South American issues. Â It is the only regularly scheduled magazine program in the English language exploring Latin American issues.\u003c/div\u003e\u003cdiv\u003e\u003cbr /\u003e\u003c/div\u003e\u003cdiv\u003eCCTV America programming can be seen from 3pm EST\u003c/div\u003e\u003cdiv\u003eCOMCAST Channel 273, FIOS 277 in the greater Washington area.\u003c/div\u003e\u003cdiv\u003eIn New York watch Time Warner Channel 134.\u003c/div\u003e\u003cdiv\u003eIn Los Angeles watch Charter Cable Channel 562.\u003c/div\u003e\u003cdiv\u003eNationwide watch DISH TV channel 279.\u003c/div\u003e\u003cdiv\u003eCheck your cable TV listings for availability in different US locations.\u003c/div\u003e\u003cdiv\u003eExcerpts of all programming can be seen on \u003ca href=\"http://www.cctv-america.com\" rel=\"nofollow\" target=\"_blank\"\u003ewww.cctv-america.com\u003c/a\u003e.\u003c/div\u003e\u003cdiv\u003e\u003cbr /\u003e\u003c/div\u003e", "url": "https://plus.google.com/105608978310637089588", "image": {  "url": "https://lh4.googleusercontent.com/-xiA6h0u4IO8/AAAAAAAAAAI/AAAAAAAAAMQ/Hv4BxXfO-_Q/photo.jpg?sz=50",  "isDefault": false }, "organizations": [  {   "name": "CCTV America",   "type": "work",   "startDate": "2012",   "primary": true  } ], "placesLived": [  {   "value": "Washington, D.C., DC 20002, United States",   "primary": true  } ], "isPlusUser": true, "circledByCount": 101, "verified": false, "cover": {  "layout": "banner",  "coverPhoto": {   "url": "https://lh3.googleusercontent.com/-c5Kov6t3y2o/U2KUhNrAClI/AAAAAAAAAME/RZEIUxBcMnk/s630-fcrop64=1,3ceb2465cd58ffff/facebook_banner.png",   "height": 347,   "width": 940  },  "coverInfo": {   "topImageOffset": 0,   "leftImageOffset": 0  } }}

现在我的问题是如何迭代placeLived来获取值。

Answer 1

您可以使用高级for循环获取entrySet()并进行迭代。 Map.Entry类在地图中代表一对，它有两个属性key和value

for(Map<String, String> map : placesLived){
    Set<Map.Entry<String, String>> entrySet = map.entrySet();    
    for (Map.Entry<String, String> entry : entrySet) {
        String key = entry.getKey();
        String value = entry.getValue();
    }
}

Answer 2

要迭代地图集合，您可以使用它：

for(Map<String, String> map : placesLived) {
    for(Map.Entry<String, String> entry : map.entrySet()) {
         String key = entry.getKey();
         String value = entry.getValue();

    }
}

希望这有帮助

Answer 3

我刚刚检查Google's javadoc的返回类型为GPObject_PublicUser.placesLived。

Iterator<Map<String, String>> iterator = placesLived.iterator(); 

while (iterator.hasNext()) {
    Map<String, String> place = iterator.next();
        for (Map.Entry<String, String> entry : place.entrySet()) {
            String placeVar1 = entry.getKey();
            String placeVar2 = entry.getValue();
             // TODO 
        }
    }
}

作为一个温和的建议 - 注意java集合，它们是我们最好的武器之一;）

在java中迭代map的集合

3 个答案: