java和json互转

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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);
}
}