使用Jackson替换Fastjson

前言

我们常用的json解析工具包括：阿里的Fastjson、Jackson和google的Gson，据测试，Fastjson较Jackson快了20%左右，Gson最慢。所以很多程序猿喜欢使用Fastjson。但是阿里提供的Fastjson近期频繁爆出安全漏洞，同时本着最小依赖原则，建议使用Jackson替换Fastjson

需要的依赖

<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-databind</artifactId>
    <version>2.9.5</version>
</dependency>
<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-core</artifactId>
    <version>2.9.5</version>
</dependency>
<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-annotations</artifactId>
    <version>2.9.5</version>
</dependency>

用法示例

1. ObjectNode与ArrayNode
   当我们需要操作一个json对象或者json数组的时候，我们可以使用下面的方法来构造ObjectNode和ArrayNode，类似fastjson中的JSONObject和JSONArray。

    ObjectMapper mapper = new ObjectMapper();
    ObjectNode node = mapper.createObjectNode();
    node.put("name", "test");
    node.put("age", 20);
    System.out.println(node);

    ArrayNode array = mapper.createArrayNode();
    array.add(node);
    System.out.println(array);

2. json转对象

    ObjectMapper objectMapper = new ObjectMapper();
    Person person = objectMapper.readValue(jsonString, Person.class);
    System.out.println(person.toString());

3. 对象转json

    ObjectMapper objectMapper = new ObjectMapper();
    Person person = new Person().setName("test").setAge(20);
    String jsonString = objectMapper.writeValueAsString(person);
    System.out.println("JsonString: " + jsonString);

4. json转泛型对象

    ObjectMapper objectMapper = new ObjectMapper();
    List<Person> personList = objectMapper.readValue(jsonString, new TypeReference<List<Person>>() {});
    System.out.println(personList.toString());