如何使用 Java 中的 Jackson 库忽略 JSON 对象的字段?\
javajsonobject oriented programmingprogramming
Jackson @JsonIgnore 注释可用于忽略 Java 对象的某个属性或字段。在将 JSON 读入 Java 对象时以及在将 Java 对象写入 JSON 时都可以忽略该属性。我们可以使用 ObjectMapper 类的 readValue() 和 writeValueAsString() 方法将 JSON 读入 Java 对象以及将 Java 对象写入 JSON。
语法
@Target(value={ANNOTATION_TYPE,METHOD,CONSTRUCTOR,FIELD}) @Retention(value=RUNTIME) public @interface JsonIgnore
示例
import java.io.*; import com.fasterxml.jackson.annotation.*; import com.fasterxml.jackson.databind.*; public class JsonIgnoreTest { public static void main(String[] args) throws IOException { Customer customer = new Customer("110", "Surya Kiran", "Chennai"); System.out.println(customer); ObjectMapper mapper = new ObjectMapper(); String jsonString = mapper.writeValueAsString(customer); System.out.println("JSON: " + jsonString); System.out.println("---------"); jsonString = "{\"id\":\"120\",\"name\":\"Devaraj\", \"address\":\"Banglore\"}"; System.out.println("JSON: " + jsonString); customer = mapper.readValue(jsonString, Customer.class); System.out.println(customer); } } // Customer classclass Customer { private String id; private String name; @JsonIgnore private String address; public Customer() { } public Customer(String id, String name, String address) { this.id = id; this.name = name; this.address = address; } public String getId() { return id; } public String getName() { return name; } public String getAddress() { return address; } @Override public String toString() { return "Customer [id=" + id + ", name=" + name + ", address=" + address + "]"; } }
输出
Customer [id=110, name=Surya Kiran, address=Chennai] JSON: {"id":"110","name":"Surya Kiran"} --------- JSON: {"id":"120","name":"Devaraj", "address":"Banglore"} Customer [id=120, name=Devaraj, address=null]