JSON
1. json是什么
它是js提供的一种数据交换格式！
2. json的语法
{}：是对象！
属性名必须使用双引号括起来！单引不行！！！
属性值：null，数值，字符串，数组：使用[]括起来，boolean值：true和false
3. 应用json
var person = {"name":"zhangSan", "age":18, "sex":"male"};
4. json与xml比较
可读性：XML胜出
解析难度：JSON本身就是JS对象（主场作战），所以简单很多
流行度：XML已经流行好多年，但在AJAX领域，JSON更受欢迎。
json-lib
1. 是什么？
它可以把javabean转换成json串
2. jar包
json-lib的核心jar包有：
json-lib.jar
json-lib的依赖jar包有：
commons-lang.jar
commons-beanutils.jar
commons-logging.jar
commons-collections.jar
ezmorph.jar
3. 核心类
JSONObject --> Map
toString();
JSONObject map = JSONObject.fromObject(person)：把对象转换成JSONObject对象
JSONArray --> List
toString()
JSONArray jsonArray = JSONObject.fromObject(list)：把list转换成JSONArray对象
应用案例：
import java.util.ArrayList;
import java.util.List;
import net.sf.json.JSONArray;
import net.sf.json.JSONObject;
import org.junit.Test;
/**
* 演示JSON-LIB小工具
*/
public class Demo1 {
//当map来用
@Test
public void fun1() {
JSONObject map = new JSONObject();
map.put("name", "zhangSan");
map.put("age", 23);
map.put("sex", "male");
String s = map.toString();
System.out.println(s);
//输出：{"name":"zhangSan","age":23,"sex":"male"}
}
//当你已经有一个Person对象时，可以把Person转换成JSONObject对象
@Test
public void fun2() {
Person p = new Person("liSi", 32, "female");
// 把对象转换成JSONObject类型
JSONObject map = JSONObject.fromObject(p);
System.out.println(map);
//输出：{"age":32,"name":"liSi","sex":"female"}
}
//JSONArray
@Test
public void fun3() {
Person p1 = new Person("zhangSan", 23, "male");
Person p2 = new Person("liSi", 32, "female");
JSONArray list = new JSONArray();
list.add(p1);
list.add(p2);
System.out.println(list.toString());
//输出：[{"age":23,"name":"zhangSan","sex":"male"},{"age":32,"name":"liSi","sex":"female"}]
}
//原来就有一个List，我们需要把List转换成JSONArray
@Test
public void fun4() {
Person p1 = new Person("zhangSan", 23, "male");
Person p2 = new Person("liSi", 32, "female");
List<Person> list = new ArrayList<Person>();
list.add(p1);
list.add(p2);
System.out.println(JSONArray.fromObject(list).toString());
//输出：[{"age":23,"name":"zhangSan","sex":"male"},{"age":32,"name":"liSi","sex":"female"}]
}
}
public class Person {
private String name;
private int age;
private String sex;
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 getSex() {
return sex;
}
public void setSex(String sex) {
this.sex = sex;
}
public Person() {
super();
// TODO Auto-generated constructor stub
}
public Person(String name, int age, String sex) {
super();
this.name = name;
this.age = age;
this.sex = sex;
}
@Override
public String toString() {
return "Person [name=" + name + ", age=" + age + ", sex=" + sex + "]";
}
}
Person