Jackson framework technology in the Java class library

The Jackson framework is the JSON processing library commonly used in the Java class library. It provides the ability to convert the Java object to JSON format. At the same time, it can also be converted to Java objects.The framework was developed and maintained by the FasterXML team. The following is the technical principle of the Jackson framework in the Java library: 1. Object mapping: Jackson framework uses annotations to mark the attributes in the Java class to indicate how to map the field of the Java object to the JSON property.Common annotations include @JSONPROPERTY, which specifies the name of the JSON attribute; @jsonignore is used to ignore certain attributes; @jsonCreator is used to specify the constructor or static method to create objects. For example, assuming that there is a Java class called Person: public class Person { @JsonProperty("name") private String name; @JsonProperty("age") private int age; // Construct function, Getter, and Setter method } In the above example, the@jsonproperty annotation specifies the name of the name property in JSON, and the name of the Age attribute in JSON is "Age". 2. Serialization: The core function of the Jackson framework is to convert the Java object into a JSON string. This process is called serialization.It can be implemented through the following code example: ObjectMapper objectMapper = new ObjectMapper(); Person person = new Person("John", 25); String jsonString = objectMapper.writeValueAsString(person); In the above code, the ObjectMapper class is the core class of the Jackson framework, which is responsible for the serialization and derivative operation of the object.WriteValueASSTRING () method converts the Person object to a JSON string. 3. Revitalization: The Jackson framework also supports converting the JSON string into a Java object. This process is called derivative.The following is an example: String jsonString = "{\"name\":\"John\",\"age\":25}"; Person person = objectMapper.readValue(jsonString, Person.class); In the above code, the Readvalue () method converts the JSON string into a Person object. 4. Support complex objects: Jackson framework also supports processing complex objects, such as nested objects, sets, MAPs, etc.It can easily handle the serialization and device of these objects. The Jackson framework is a high -performance JSON processing library, which is widely used in the Java library.Through the above technical principles and examples, you can better understand the working principles and usage of the Jackson framework in the Java library.