FastJson是阿里巴巴团队开发出一种开源工具。其作用可以讲JavaBean，集合，map集合转化为json格式的字符串。使用起来很方便。
首先下载阿里巴巴的fastjson-1.1.27.jar包，然后将其导入到项目当中。就可以实现json字符串与对象之间转换（toJsonString和parSEObject）,转换过的对象可以通过getxxx(属性名)获取到对应的值；
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下面是我写的几个测试的例子：
对象
@Test
public void fun(){
Student st = new Student("Jim","110","USA");
String str = JSON.toJSONString(st);
System.out.println(str);
}
集合
@Test
public void fun1(){
Student st1 = new Student("Jim1","1101","USA1");
Student st2 = new Student("Jim2","1102","USA2");
Student st3 = new Student("Jim3","1103","USA3");
List<Student> list = new ArrayList<Student>();
list.add(st1);
list.add(st2);
list.add(st3);
String str = JSON.toJSONString(list);
System.out.println(str);
}
map集合
@Test
public void fun4(){
Map<String,Student> map = new HashMap<String,Student>();
Student st1 = new Student("Jim1","USA3");
map.put("one",st1);
map.put("two",st2);
map.put("three",st3);
String str = JSON.toJSONString(map);
System.out.println(str);
}