Fastjson

1.String<->JsonObject（JSONObject对象不存在，只能用类名.静态方法）（parse是反序列化，由字符串变成其他类型，可以理解为将字符串解析为什么什么类型。）

 JSONObject jsonObject = JSONObject.parseObject(jsonString); 

 String jsonString = jsonObject.toJSONString();

2.String<->JsonArray

JSONArray jsonArray = JSONArray.parseArray(jsonString);

String jsonString = jsonArray.toJSONString();//JSONArray.toJSONString(jsonArray);

3.JsonObject->JavaBean(JSONObject对象已存在，可以调用对象方法)

Student student = JSONObject.parseObject(jsonObject.toJSONString(), Student.class);

JSONObject studentJson = JSONObject.parseObject(JSONObject.toJSONString(student));

4.String<->JavaBean

JavaBean  javaBean  = JSONObject.parseObject(jsonString, JavaBean.class);

String jsonString = JSONObject.toJSONString(javaBean); // 将Java对象序列化为JSON字符串，支持各种各种Java基本类型和JavaBean

5.String<->JavaBeanList

List<Student> studentList = JSONArray.parseArray(josnArrayString, Student.class);

List<Student> students = new ArrayList<Student>();   

String jsonString = JSONArray.toJSONString(students);

序列化API

package com.alibaba.fastjson;

public abstract class JSON {
    // 将Java对象序列化为JSON字符串，支持各种各种Java基本类型和JavaBean
    public static String toJSONString(Object object, SerializerFeature... features);

    // 将Java对象序列化为JSON字符串，返回JSON字符串的utf-8 bytes
    public static byte[] toJSONBytes(Object object, SerializerFeature... features);

    // 将Java对象序列化为JSON字符串，写入到Writer中
    public static void writeJSONString(Writer writer, 
                                       Object object, 
                                       SerializerFeature... features);

    // 将Java对象序列化为JSON字符串，按UTF-8编码写入到OutputStream中
    public static final int writeJSONString(OutputStream os, // 
                                            Object object, // 
                                            SerializerFeature... features);

}

反序列化

package com.alibaba.fastjson;

public abstract class JSON {
    // 将JSON字符串反序列化为JavaBean
    public static <T> T parseObject(String jsonStr, 
                                    Class<T> clazz, 
                                    Feature... features);

    // 将JSON字符串反序列化为JavaBean
    public static <T> T parseObject(byte[] jsonBytes,  // UTF-8格式的JSON字符串
                                    Class<T> clazz, 
                                    Feature... features);

    // 将JSON字符串反序列化为泛型类型的JavaBean
    public static <T> T parseObject(String text, 
                                    TypeReference<T> type, 
                                    Feature... features);

    // 将JSON字符串反序列为JSONObject
    public static JSONObject parseObject(String text);
}