java和json互转

在网页中想后台传递多个数据时，有时数据还是多个动态列表，数据很复杂时，JavaScript程序员喜欢把他们作为json串进行处理，后台收到后需要对json字符串进行解析，幸好有JSON-lib，这个Java类包用于把bean,map和XML转换成JSON并能够把JSON转回成bean和DynaBean。
下载地址:http://json-lib.sourceforge.net/

  1 public class Test {
  2
  3 /**
  4
  5 * @param args
  6
  7 * @author wen
  8
  9 */
 10
 11 public static void main(String[] args) {
 12
 13 //            test1();
 14
 15 //            test2();
 16
 17 String json = “{1:{1:{jhinfo:['计划一','亲亲宝宝','www.wenhq.com'],jhrate:['1-5:10.0','6-100:5.0/1']},2:{jhinfo:['计划二','亲亲宝宝','www.wenhq.com'],jhrate:['1-100:100.0']},3:{jhinfo:['计划三','亲亲宝宝','www.wenhq.com'],jhrate:['1-100:150.0/7']}},2:{4:{jhinfo:['年计划','亲亲宝宝','www.wenhq.com'],jhrate:['365-365:1000.0']}}}”;
 18
 19 try {
 20
 21 JSONObject jsonObject = JSONObject.fromObject(json);
 22
 23 String name = jsonObject.getString(“1″);
 24
 25 String address = jsonObject.getString(“2″);
 26
 27 System.out.println(“name is:” + name);
 28
 29 System.out.println(“address is:” + address);
 30
 31 Iterator it=jsonObject.keys();
 32
 33 while (it.hasNext()){
 34
 35 System.out.println(jsonObject.get(it.next()));
 36
 37 }
 38
 39 } catch (JSONException e) {
 40
 41 e.printStackTrace();
 42
 43 }
 44
 45 }
 46
 47 /**
 48
 49 * json对象字符串转换
 50
 51 * @author wen
 52
 53 */
 54
 55 private static void test2() {
 56
 57 String json = “{‘name’: ‘亲亲宝宝’,'array’:[{'a':'111','b':'222','c':'333'},{},{'a':'999'}],’address’:'亲亲宝宝’}”;
 58
 59 try {
 60
 61 JSONObject jsonObject = JSONObject.fromObject(json);
 62
 63 String name = jsonObject.getString(“name”);
 64
 65 String address = jsonObject.getString(“address”);
 66
 67 System.out.println(“name is:” + name);
 68
 69 System.out.println(“address is:” + address);
 70
 71 JSONArray jsonArray = jsonObject.getJSONArray(“array”);
 72
 73 for (int i = 0; i < jsonArray.size(); i++) {
 74
 75 System.out.println(“item ” + i + ” :” + jsonArray.getString(i));
 76
 77 }
 78
 79 } catch (JSONException e) {
 80
 81 e.printStackTrace();
 82
 83 }
 84
 85 }
 86
 87 /**
 88
 89 * json数组 转换，数组以[开头
 90
 91 * @author wen
 92
 93 */
 94
 95 private static void test1() {
 96
 97 boolean[] boolArray = new boolean[]{true,false,true};
 98
 99 JSONArray jsonArray1 = JSONArray.fromObject( boolArray );
100
101 System.out.println( jsonArray1 );
102
103 // prints [true,false,true]
104
105 List list = new ArrayList();
106
107 list.add( “first” );
108
109 list.add( “second” );
110
111 JSONArray jsonArray2 = JSONArray.fromObject( list );
112
113 System.out.println( jsonArray2 );
114
115 // prints ["first","second"]
116
117 JSONArray jsonArray3 = JSONArray.fromObject( “['json','is','easy']” );
118
119 System.out.println( jsonArray3 );
120
121 // prints ["json","is","easy"]
122
123 }

从json数组中得到相应java数组，如果要获取java数组中的元素，只需要遍历该数组。

 1   /**
 2       * 从json数组中得到相应java数组
 3       * JSONArray下的toArray()方法的使用
 4       * @param str
 5       * @return
 6       */
 7       public static Object[] getJsonToArray(String str) {
 8           JSONArray jsonArray = JSONArray.fromObject(str);
 9           return jsonArray.toArray();
10       }
11
12    public static void main(String[] args) {
13         JSONArray jsonStrs = new JSONArray();
14         jsonStrs.add(0, "cat");
15         jsonStrs.add(1, "dog");
16         jsonStrs.add(2, "bird");
17         jsonStrs.add(3, "duck");
18
19         Object[] obj=getJsonToArray(jsonStrs.toString());
20         for(int i=0;i<obj.length;i++){
21               System.out.println(obj[i]);
22         }
23     }

从json数组中得到java数组，可以对该数组进行转化，如将JSONArray转化为String型、Long型、Double型、Integer型、Date型等等。 
分别采用jsonArray下的getString(index)、getLong(index)、getDouble(index)、getInt(index)等方法。 
同样，如果要获取java数组中的元素，只需要遍历该数组。

 1      /**
 2       * 将json数组转化为Long型
 3       * @param str
 4       * @return
 5       */
 6      public static Long[] getJsonToLongArray(String str) {
 7           JSONArray jsonArray = JSONArray.fromObject(str);
 8           Long[] arr=new Long[jsonArray.size()];
 9           for(int i=0;i<jsonArray.size();i++){
10               arr[i]=jsonArray.getLong(i);
11               System.out.println(arr[i]);
12           }
13           return arr;
14     }
15      /**
16       * 将json数组转化为String型
17       * @param str
18       * @return
19       */
20      public static String[] getJsonToStringArray(String str) {
21           JSONArray jsonArray = JSONArray.fromObject(str);
22           String[] arr=new String[jsonArray.size()];
23           for(int i=0;i<jsonArray.size();i++){
24               arr[i]=jsonArray.getString(i);
25               System.out.println(arr[i]);
26           }
27           return arr;
28     }
29      /**
30       * 将json数组转化为Double型
31       * @param str
32       * @return
33       */
34      public static Double[] getJsonToDoubleArray(String str) {
35           JSONArray jsonArray = JSONArray.fromObject(str);
36           Double[] arr=new Double[jsonArray.size()];
37           for(int i=0;i<jsonArray.size();i++){
38               arr[i]=jsonArray.getDouble(i);
39           }
40           return arr;
41     }
42      /**
43       * 将json数组转化为Date型
44       * @param str
45       * @return
46       */
47      public static Date[] getJsonToDateArray(String jsonString) {
48
49           JSONArray jsonArray = JSONArray.fromObject(jsonString);
50           Date[] dateArray = new Date[jsonArray.size()];
51           String dateString;
52           Date date;
53           SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd");
54           for (int i = 0; i < jsonArray.size(); i++) {
55               dateString = jsonArray.getString(i);
56               try {
57                   date=sdf.parse(dateString);
58                   dateArray[i] = date;
59               } catch (Exception e) {
60                   e.printStackTrace();
61               }
62           }
63           return dateArray;
64     }
65
66
67  public static void main(String[] args) {
68
69         JSONArray jsonLongs = new JSONArray();
70         jsonLongs.add(0, "111");
71         jsonLongs.add(1, "222.25");
72         jsonLongs.add(2, new Long(333));
73         jsonLongs.add(3, 444);
74
75         Long[] log=getJsonToLongArray(jsonLongs.toString());
76         for(int i=0;i<log.length;i++){
77             System.out.println(log[i]);
78         }
79
80         JSONArray jsonStrs = new JSONArray();
81         jsonStrs.add(0, "2011-01-01");
82         jsonStrs.add(1, "2011-01-03");
83         jsonStrs.add(2, "2011-01-04 11:11:11");
84
85         Date[] d=getJsonToDateArray(jsonStrs.toString());
86         for(int i=0;i<d.length;i++){
87             System.out.println(d[i]);
88         }
89     }
90   /*结果如下：
91      * 111
92      * 222
93      * 333
94      * 444
95      *
96      * Sat Jan 01 00:00:00 CST 2011
97      * Mon Jan 03 00:00:00 CST 2011
98      * Tue Jan 04 00:00:00 CST 2011
99      */

/**
* java转为json对象
* @author wudouzhu
*/
public class JsonTest3 {

public static void main(String[] args) {
SimInfo s = new SimInfo();
s.setAddTime("2000-10-21");
s.setIccid("23");
s.setId("243432435435365789");
s.setImei("423");
s.setImsi("545");
s.setPhoneType("1878789887");
s.setRemark("1");
s.setTel("0518-666678");
String json = new JSONArray().fromObject(s).toString();
System.out.println("json:"+json);
//json:[{"addTime":"2000-10-21","iccid":"23","id":"243432435435365789","imei":"423","imsi":"545","phoneType":"1878789887","remark":"1","tel":"0518-666678"}]

}
}

/**
* json转为java对象
* @author wudouzhu
*/
public class JsonTest {

public static void main(String[] args) {
String json="[{\"addTime\":\"2011-09-19 14:23:02\",\"iccid\":\"1111\",\"id\":0,\"imei\":\"2222\",\"imsi\":\"3333\",\"phoneType\":\"4444\",\"remark\":\"aaaa\",\"tel\":\"5555\"}]";
if(json.indexOf("[")!=-1){
json = json.replace("[","");
}
if(json.indexOf("]")!=-1){
json = json.replace("]","");
}
JSONObject object = JSONObject.fromObject(json);
SimInfo simInfo = (SimInfo)JSONObject.toBean(object,SimInfo.class);
System.out.println("obj:"+object);
System.out.println(simInfo.getAddTime());
System.out.println(simInfo.getIccid());
System.out.println(simInfo.getId());
System.out.println(simInfo.getImei());
System.out.println(simInfo.getImsi());
System.out.println(simInfo.getPhoneType());
System.out.println(simInfo.getRemark());
System.out.println(simInfo.getTel());
}
}

/**
* json转为java集合对象
* @author wudouzhu
*/
public class JsonTest2 {

public static void main(String[] args) {
JsonTest2 t = new JsonTest2();
String jsons="[{\"addTime\":\"2011-09-19 14:23:02\",\"iccid\":\"1111\",\"id\":0,\"imei\":\"2222\",\"imsi\":\"3333\",\"phoneType\":\"4444\",\"remark\":\"aaaa\",\"tel\":\"5555\"}," +
"{\"addTime\":\"2011-11-11 14:23:02\",\"iccid\":\"2222\",\"id\":0,\"imei\":\"2222\",\"imsi\":\"3333\",\"phoneType\":\"4444\",\"remark\":\"aaaa\",\"tel\":\"5555\"}]";
List<SimInfo> simInfos = t.getJavaCollection(new SimInfo(),jsons);
System.out.println("size:"+simInfos.size());
for(SimInfo s:simInfos){
System.out.println("addTime:"+s.getAddTime());
System.out.println("==========");
}
}
/*
* 封装将json对象转为java集合对象
*/
private <T> List<T> getJavaCollection(T clazz,String jsons){
List<T> objs = null;
JSONArray jsonArray = (JSONArray)JSONSerializer.toJSON(jsons);
if(jsonArray!=null){
objs = new ArrayList<T>();
List list = (List)JSONSerializer.toJava(jsonArray);
for(Object o:list){
JSONObject jsonObject = JSONObject.fromObject(o);
T obj = (T)JSONObject.toBean(jsonObject,clazz.getClass());
objs.add(obj);
}
}

return objs;
}

}