fasterxml Jackson序列化与反序列化实现，基本使用以及高级特性测试

桃扇骨 2023-02-16 04:05 13阅读 0赞

### 基本使用以及高级特性测试 ###

*   *  写在前面
     *  一、简单操作
     *   *  1.1、String to Object
         *  1.2、file to Object
         *  1.3、string to map
         *  1.4、写测试1
         *  1.5、写测试2
         *  1.6、时间转换1
         *  1.7、时间转换2
         *  1.8、jsonNode
     *  二、高级特性
     *   *  2.1、SerializationFeature
         *   *  2.1.1、
         *  2.2、DeserializationFeature
         *   *  2.2.1、
     *  三、注解使用

## 写在前面 ##

## 一、简单操作 ##

### 1.1、String to Object ###

/** * json string to Object * * @throws JsonProcessingException */
        @Test
        public void t1() throws JsonProcessingException { 
            String carJson = "{ " +
                    "\"brand\" : \"Mercedes\"," +
                    "\"doors\" : 5 " +
                    "}";
            Car car = objectMapper.readValue(carJson, Car.class);
    
            System.out.println("car brand = " + car.getBrand());
            System.out.println("car doors = " + car.getDoors());
            System.out.println(objectMapper.writeValueAsString(car));
        }

/** * Car{brand='ford', doors=0} * Car{brand='Fiat', doors=0} * * @throws IOException */
        @Test
        public void t2_2() throws IOException { 
            String jsonArray = "[{\"brand\":\"ford\"}, {\"brand\":\"Fiat\"}]";
            ObjectMapper objectMapper = new ObjectMapper();
            List<Car> cars1 = objectMapper.readValue(jsonArray, new TypeReference<List<Car>>() { 
            });
            cars1.forEach(System.out::println);
        }

### 1.2、file to Object ###

/** * json File to Object * <p> * {"brand":"Mercedes","doors":5} * * @throws JsonProcessingException */
        @Test
        public void t2() throws IOException { 
    
            File file = new File("D:\\GitRepository\\multiProject\\Jackson\\src\\test\\resources\\json\\car.json");
    
            Car car = objectMapper.readValue(file, Car.class);
            System.out.println(objectMapper.writeValueAsString(car));
        }

/** * { * "brand": "Mercedes", * "doors": 5 * } * tonels.domian.Car@78e67e0a * * @throws IOException */
        @Test
        public void t2_1() throws IOException { 
            String resource = "json/car.json";
            InputStream is = Thread.currentThread().getContextClassLoader().getResourceAsStream(resource);
            String text = IOUtils.toString(is);
            System.out.println(text);
    
            final Car car = objectMapper.readValue(text, Car.class);
            System.out.println(car.toString());
        }

### 1.3、string to map ###

/** * {brand=ford, doors=5} * * @throws IOException */
        @Test
        public void t2_3() throws IOException { 
            String jsonObject = "{\"brand\":\"ford\", \"doors\":5}";
            ObjectMapper objectMapper = new ObjectMapper();
            Map<String, Object> jsonMap = objectMapper.readValue(jsonObject,
                    new TypeReference<Map<String, Object>>() { 
                    });
            System.out.println(jsonMap);
        }

### 1.4、写测试1 ###

/** * 写测试 * @throws IOException */
        @Test
        public void t3() throws IOException { 
            Car car = new Car();
            car.setBrand("BMW" );
            car.setDoors(4) ;
            objectMapper.writeValue(
                    new FileOutputStream("json/output-2.json"), car);
        }

### 1.5、写测试2 ###

/** * {"brand":"BMW","doors":4} * @throws IOException */
        @Test
        public void t3_1() throws IOException { 
            Car car = new Car();
            car.setBrand("BMW" );
            car.setDoors(4) ;
            String json = objectMapper.writeValueAsString(car);
            System.out.println(json);
        }

### 1.6、时间转换1 ###

/** * {"type":"transfer","date":1591519578900} * @throws IOException */
        @Test
        public void t4() throws IOException { 
            Transaction transaction = new Transaction("transfer", new Date());
            String output = objectMapper.writeValueAsString(transaction);
            System.out.println(output);
        }

### 1.7、时间转换2 ###

/** * {"type":"transfer","date":"2020-06-07"} * @throws IOException */
        @Test
        public void t4_1() throws IOException { 
            SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd");
            objectMapper.setDateFormat(dateFormat);
    
            Transaction transaction = new Transaction("transfer", new Date());
            String output2 = objectMapper.writeValueAsString(transaction);
            System.out.println(output2);
        }

### 1.8、jsonNode ###

/** * * brand = Mercedes * doors = 5 * john = * field = value * @throws IOException */
        @Test
        public void t5_1() throws IOException { 
            String carJson =
                    "{ \"brand\" : \"Mercedes\", \"doors\" : 5," +
                            " \"owners\" : [\"John\", \"Jack\", \"Jill\"]," +
                            " \"nestedObject\" : { \"field\" : \"value\" } }";
            try { 
                JsonNode jsonNode = objectMapper.readValue(carJson, JsonNode.class);
    
                JsonNode brandNode = jsonNode.get("brand");
                String brand = brandNode.asText();
                System.out.println("brand = " + brand);
    
                JsonNode doorsNode = jsonNode.get("doors");
                int doors = doorsNode.asInt();
                System.out.println("doors = " + doors);
    
                JsonNode array = jsonNode.get("owners");
                JsonNode jsonNode1 = array.get(0);
                String john = jsonNode.asText();
                System.out.println("john = " + john);
    
                JsonNode child = jsonNode.get("nestedObject");
                JsonNode childField = child.get("field");
                String field = childField.asText();
                System.out.println("field = " + field);
    
            } catch (IOException e) { 
                e.printStackTrace();
            }
        }

## 二、高级特性 ##

这里主要包括 SerializationFeature 和 DeserializationFeature 两个枚举对象

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### 2.1、SerializationFeature ###

#### 2.1.1、 ####

### 2.2、DeserializationFeature ###

#### 2.2.1、 ####

待补充

## 三、注解使用 ##

待补充

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