如何使用Jackson遍历JSON对象？

<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-core</artifactId>
    <version>2.12.3</version>
</dependency>
<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-databind</artifactId>
    <version>2.12.3</version>
</dependency>

ObjectMapper objectMapper = new ObjectMapper();

String json = "{\"name\":\"John\",\"age\":30,\"city\":\"New York\"}";
JsonNode rootNode = objectMapper.readTree(json);

String name = rootNode.get("name").asText();
int age = rootNode.get("age").asInt();
String city = rootNode.get("city").asText();

Iterator<String> fieldNames = rootNode.fieldNames();
while (fieldNames.hasNext()) {
    String fieldName = fieldNames.next();
    JsonNode fieldValue = rootNode.get(fieldName);
    // 处理属性值
}

Iterator<Map.Entry<String, JsonNode>> fields = rootNode.fields();
while (fields.hasNext()) {
    Map.Entry<String, JsonNode> field = fields.next();
    String fieldName = field.getKey();
    JsonNode fieldValue = field.getValue();
    // 处理属性和值
}