数据绑定
树模型
流式API

测试数据
{"id":1,"name":"Department1","users":[{"id":1,"name":"cat"},{"id":2,"name":"tiger"}]}


数据绑定
ObjectMapper mapper = new ObjectMapper();
Department dept = mapper.readValue(json, Department.class);
System.out.println(dept);


树模型

JsonNode rootNode = mapper.readTree(json);
System.out.println(rootNode);
JsonNode idNode = rootNode.get("id");
JsonNode nameNode = rootNode.get("name");
JsonNode nullNode = rootNode.get("xxx");
JsonNode nullNodeByPath = rootNode.path("xxx");

System.out.println("idNode="+idNode);
System.out.println("nameNode="+nameNode);
System.out.println("nullNode="+nullNode);
System.out.println("nullNodeByPath="+nullNodeByPath);
        
System.out.println("idNode isArray "+idNode.isArray());
System.out.println("idNode size "+idNode.size());

System.out.println("idNode "+idNode.asInt() +" "+idNode.asText());

JsonNode usersNode = rootNode.get("users");
System.out.println("usersNode="+usersNode);
        
if(usersNode.isArray()) {
  int size = usersNode.size();
    for(int i=0;i < size;i++) {
      JsonNode userNode = usersNode.get(0);
      System.out.println("userNodes["+i+"]="+userNode);
    }
}


流式API

JsonFactory factory = new JsonFactory();

JsonParser parser = factory.createParser(json);
while (!parser.isClosed()){
  JsonToken token = parser.currentToken();
  System.out.println(token);
  parser.nextToken();
}   

START_OBJECT
FIELD_NAME
VALUE_NUMBER_INT
FIELD_NAME
VALUE_STRING
FIELD_NAME
START_ARRAY
START_OBJECT
FIELD_NAME
VALUE_NUMBER_INT
FIELD_NAME
VALUE_STRING
END_OBJECT
START_OBJECT
FIELD_NAME
VALUE_NUMBER_INT
FIELD_NAME
VALUE_STRING
END_OBJECT
END_ARRAY
END_OBJECT
            


完整代码
https://gitee.com/dyyx/demos/blob/master/jackson/src/main/java/dyyx/jackson/TestAll.java