JSONObject.fromObject--JSON与对象的转换

JSON与JAVA数据的转换（JSON 即 JavaScript Object Natation，它是一种轻量级的数据交换格式，非常适合于服务器与 JavaScript 的交互。）

代码中有这么一句，是后台的封装数据。

JSONObject jo = JSONObject.fromObject(map);
常见的java代码转换成json

--请注意，这个方法曾经给我造成过困惑。因为，它在对Object转换的时候是按照domain类中的所有getXXX()方法进行转换的。如果你在类中写了非属性的getXXX()方法，那么返回给你的就会有XXX属性了。

--使用net.sf.json.*下的类（jar包是json-lib-x.x.jar）

1. List集合转换成json代码

List list = new ArrayList();

list.add( "first" );

list.add( "second" );

JSONArray jsonArray2 = JSONArray.fromObject( list );

2. Map集合转换成json代码

Map map = new HashMap();

map.put("name", "json");

map.put("bool", Boolean.TRUE);

map.put("int", new Integer(1));

map.put("arr", new String[] { "a", "b" });

map.put("func", "function(i){ return this.arr[i]; }");

JSONObject json = JSONObject.fromObject(map);

3. Bean转换成json代码

JSONObject jsonObject = JSONObject.fromObject(new JsonBean());

4. 数组转换成json代码

boolean[] boolArray = new boolean[] { true, false, true };

JSONArray jsonArray1 = JSONArray.fromObject(boolArray);

5. 一般数据转换成json代码

JSONArray jsonArray3 = JSONArray.fromObject("['json','is','easy']" );

public static void main(String[] args) {
Map map=new HashMap();
map.put("我","妹");
map.put("擦","哇");
map.put("你","呀");
JSONObject json = JSONObject.fromObject(map);
System.out.println(json);
}

輸出的結果 {"我":"妹","擦":"哇","你":"呀"}

toBean();

首先一个javabean对象
public class Student {

private int id ;
private String name;
private int age;

public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}

public String toString(){
return this.id + ", " + this.name + ", " + this.age;
}
}

然后测试toBean方法的类
import net.sf.json.JSONObject;

public class ToBeanTest {

public static void main(String[] args) {

String json = "{id:'1001',name:'张三',age:'22'}";
Student stu = new Student();
JSONObject obj = JSONObject.fromObject(json);
stu = (Student)JSONObject.toBean(obj, Student.class);
System.out.println(stu);
}

}
输出结果为1001, 张三, 22
然后我们在修改修改
import net.sf.json.JSONObject;

public class ToBeanTest {

public static void main(String[] args) {

String json = "{id:'1001',name:'张三'}";
Student stu = new Student();
JSONObject obj = JSONObject.fromObject(json);
stu = (Student)JSONObject.toBean(obj, Student.class);
System.out.println(stu);
}

}
把年龄给去掉age为int型，输出结果为：1001, 张三, 0
然后再做小小改动
import net.sf.json.JSONObject;

public class ToBeanTest {

public static void main(String[] args) {

String json = "{id:'1001',age:'22'}";
Student stu = new Student();
JSONObject obj = JSONObject.fromObject(json);
stu = (Student)JSONObject.toBean(obj, Student.class);
System.out.println(stu);
}

}
把姓名给去掉name为String型，输出结果为：1001, null, 22
再改动一下：
import net.sf.json.JSONObject;

public class ToBeanTest {

public static void main(String[] args) {

String json = "{id:'1001',name:'张三',age:'nn'}";
Student stu = new Student();
JSONObject obj = JSONObject.fromObject(json);
stu = (Student)JSONObject.toBean(obj, Student.class);
System.out.println(stu);
}

}
把age改成非整形，输出结果为：
1001, 张三, 0

再改动一下：
import net.sf.json.JSONObject;

public class ToBeanTest {

public static void main(String[] args) {

String json = "{id:'1001',name:'张三',age:'22',sex:'男'}";
Student stu = new Student();
JSONObject obj = JSONObject.fromObject(json);
stu = (Student)JSONObject.toBean(obj, Student.class);
System.out.println(stu);
}

}
加了一个sex:'男'的一对键值，输出结果为：
1001, 张三, 22