JSON这个类是fastjson API的入口，主要的功能都通过这个类提供。
序列化API
// 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);
JSON字符串反序列化API
// 将JSON字符串反序列化为JavaBean public staticT parseObject(String jsonStr, Class clazz, Feature... features); // 将JSON字符串反序列化为JavaBean public static T parseObject(byte[] jsonBytes, // UTF-8格式的JSON字符串 Class clazz, Feature... features); // 将JSON字符串反序列化为泛型类型的JavaBean public static T parseObject(String text, TypeReference type, Feature... features); // 将JSON字符串反序列为JSONObject public static JSONObject parseObject(String text);
Demo
String jsonStr = "{ " + " \"animals\": { " + " \"dog\": [{ " + " \"name\": \"Rufus\", " + " \"breed\": \"labrador\" " + " }, " + " { " + " \"name\": \"Marty\", " + " \"breed\": \"whippet\" " + " } " + " ], " + " \"cat\": { " + " \"name\": \"Matilda\" " + " } " + " } " + "}";
parse Tree
//parse TreeJSONObject jsonObj = JSON.parseObject(jsonStr);System.out.println("jsonObj:" + jsonObj);//{"animals":{"cat":{"name":"Matilda"},"dog":[{"name":"Rufus","breed":"labrador"},{"name":"Marty","breed":"whippet"}]}}JSONObject animals = jsonObj.getJSONObject("animals");System.out.println("animals:" + animals);//{"cat":{"name":"Matilda"},"dog":[{"name":"Rufus","breed":"labrador"},{"name":"Marty",","breed":"whippet"}]}JSONArray dogArr = animals.getJSONArray("dog");System.out.println("dogArr:" + dogArr);//[{"name":"Rufus","breed":"labrador"},{"name":"Marty","breed":"whippet"}]JSONObject dog0 = dogArr.getJSONObject(0);System.out.println("dog0:" + dog0);//{"name":"Rufus","breed":"labrador"}String dog0name = dog0.getString("name");System.out.println("dog0name:" + dog0name);//Rufus parse POJO
//parse POJOJsonRootBean model = JSON.parseObject(jsonStr, JsonRootBean.class);System.out.println("model:" + model);//JsonRootBean{animals=Animals{dog=[Dog{name='Rufus', breed='labrador'}, Dog{name='Marty', breed='whippet'}], cat=Cat{name='Matilda'}}}
parse POJO Generic
//parse POJO List对象Type type = new TypeReference
>() {}.getType();// List list = JSON.parseObject(dogArr.toString(), type);List list = JSON.parseArray(dogArr.toString(), Dog.class);System.out.println("list:" + list);//[Dog{name='Rufus', breed='labrador'}, Dog{name='Marty', breed='whippet'}]
convert POJO to json string
//convert POJO to json stringString modelStr = JSON.toJSONString(model);System.out.println("modelStr:" + modelStr);//{"animals":{"cat":{"name":"Matilda"},"dog":[{"breed":"labrador","name":"Rufus"},{"breed":"whippet","name":"Marty"}]}}
convert POJO to json bytes
//convert POJO to json bytesbyte[] modelBytes = JSON.toJSONBytes(model);System.out.println("modelBytes:" + modelBytes.length);//117
参考文章:
https://www.w3cschool.cn/fastjson/fastjson-api.html