Fastjson 序列化与反序列化

墨蓝 2021-12-23 07:03 374阅读 0赞

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 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);

# Demo #

String jsonStr = "{  " +
                    "  \"animals\": {  " +
                    "    \"dog\": [{  " +
                    "        \"name\": \"Rufus\",  " +
                    "        \"breed\": \"labrador\"  " +
                    "      },  " +
                    "      {  " +
                    "        \"name\": \"Marty\",  " +
                    "        \"breed\": \"whippet\"  " +
                    "      }  " +
                    "    ],  " +
                    "    \"cat\": {  " +
                    "      \"name\": \"Matilda\"  " +
                    "    }  " +
                    "  }  " +
                    "}";

### parse Tree ###

//parse Tree
    JSONObject 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 POJO
    JsonRootBean 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<List<Dog>>() {}.getType();
    // List<Dog> list = JSON.parseObject(dogArr.toString(), type);
    List<Dog> 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 string
    String 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 bytes
    byte[] modelBytes = JSON.toJSONBytes(model);
    System.out.println("modelBytes:" + modelBytes.length);//117

参考文章:

https://www.w3cschool.cn/fastjson/fastjson-api.html

转载于:https://www.cnblogs.com/ooo0/p/10902202.html