如何使用Java中的Jackson库忽略空字段和空字段？
在杰克逊 是一个Java库，它具有非常强大的数据绑定功能，并提供了一个框架序列化自定义的Java对象，JSON和反序列化JSON回Java对象。Jackson库提供@JsonInclude批注，该批注根据序列化期间类的值来控制整个类或其单个字段的序列化。
该@JsonInclude注释包含以下两个值
Include.NON_NULL：指示仅具有非空值的属性将包含在JSON中。
Include.NON_EMPTY：指示仅非空属性将包含在JSON中
示例
import com.fasterxml.jackson.annotation.*;
import com.fasterxml.jackson.annotation.JsonInclude.Include;
import com.fasterxml.jackson.core.*;
import com.fasterxml.jackson.databind.*;
public class IgnoreNullAndEmptyFieldTest {
public static void main(String[] args) throws JsonProcessingException {
ObjectMapper mapper = new ObjectMapper();
mapper.enable(SerializationFeature.INDENT_OUTPUT);
Employee employee = new Employee(115, null, ""); // passing null and empty fields
String result = mapper.writeValueAsString(employee);
System.out.println(result);
}
}
//员工阶层
class Employee {
private int id;
@JsonInclude(Include.NON_NULL)
private String firstName;
@JsonInclude(Include.NON_EMPTY) private String lastName;
public Employee(int id, String firstName, String lastName) {
super();
this.id = id;
this.firstName = firstName;
this.lastName = lastName;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getFirstName() {
return firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
public String getLastName() {
return lastName;
}
public void setLastName(String lastName) {
this.lastName = lastName;
}
}输出结果
{
"id" : 115
}