需要的包:
1.commons-lang.jar

2.commons-beanutils.jar

3.commons-collections.jar

4.commons-logging.jar

5.ezmorph.jar

6.json-lib-2.2.2-jdk15.jar


测试的例子:
可以用这个方法JSONArray.fromObject(list).toString(); 

1 import java.util.ArrayList;
 2 import java.util.HashMap;
 3 import java.util.List;
 4 import java.util.ListIterator;
 5 import java.util.Map;
 6 
 7 import net.sf.json.JSONArray;
 8 
 9 import com.yan.entity.Student;
10 
11 public class List2Json {
12 
13     public static void main(String[] args) {
14         List<Object> list = new ArrayList<Object>();
15         List<Map<String, Object>> sublist = new ArrayList<Map<String, Object>>();
16         Map<String, Object> map = new HashMap<String, Object>();
17 
18         map.put("abc", "123456");
19         map.put("def", "hmm");
20         map.put("defddf", "ftffff");
21         list.add(map);
22         
23         Map<String, Object> map1 = new HashMap<String, Object>();
24         map1.put("fff", "hhhh");
25         map1.put("ggg", "jjj");
26         map1.put("kk", "dffff");
27         sublist.add(map1);
28         
29         Student st = new Student();
30         st.setSid(1);
31         st.setName("alec");
32         st.setTeacher("scott");
33         
34         list.add(st);
35         
36         list.add(sublist);
37         JSONArray json = new JSONArray();
38         json.addAll(list);
39         json.listIterator();
40         if(json.isEmpty()){
41             System.out.println("dfdfdf");
42         }
43         ListIterator  li = json.listIterator();
44         while(li.hasNext()){
45             System.out.println(li.next().toString());
46         }
47     }
48 
49 }

上面用到的一个简单的entity

1 public class Student {
 2     
 3     public Integer sid;
 4     public String name;
 5     public String teacher;
 6     
 7     public Integer getSid() {
 8         return sid;
 9     }
10     public void setSid(Integer sid) {
11         this.sid = sid;
12     }
13     public String getName() {
14         return name;
15     }
16     public void setName(String name) {
17         this.name = name;
18     }
19     public String getTeacher() {
20         return teacher;
21     }
22     public void setTeacher(String teacher) {
23         this.teacher = teacher;
24     }
25 }