何时在 Java 中使用 Jackson 的 @JsonManagedReference 和 @JsonBackReference 注释?
javajsonobject oriented programmingprogramming
@JsonManagedReference 和 @JsonBackReference 注释可用于以双向 方式创建 JSON 结构。@JsonManagedReference 注释是在序列化过程中包含的前向引用，而@JsonBackReference 注释是在序列化过程中省略的反向引用。
在下面的示例中，我们可以实现 @JsonManagedReference 和 @JsonBackReference 注释。
示例
import java.util.*;
import com.fasterxml.jackson.annotation.JsonManagedReference;
import com.fasterxml.jackson.annotation.JsonBackReference;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.core.JsonProcessingException;
public class ManagedReferenceBackReferenceTest {
public static void main(String args[]) throws JsonProcessingException {
BackReferenceBeanTest testBean = new BackReferenceBeanTest(110, "Sai Chaitanya");
ManagedReferenceBeanTest bean = new ManagedReferenceBeanTest(135, "Adithya Ram", testBean);
testBean.addEmployees(bean);
ObjectMapper mapper = new ObjectMapper();
String jsonString = mapper.writerWithDefaultPrettyPrinter().writeValueAsString(bean);
System.out.println(jsonString);
}
}
class ManagedReferenceBeanTest {
public int empId = 115;
public String empName = "Raja Ramesh";
@JsonManagedReference
public BackReferenceBeanTest manager;
public ManagedReferenceBeanTest(int empId, String empName, BackReferenceBeanTest manager) {
this.empId = empId;
this.empName = empName;
this.manager = manager;
}
}
class BackReferenceBeanTest {
public int empId = 125;
public String empName = "Jai Dev";
@JsonBackReference
public List<ManagedReferenceBeanTest> list;
public BackReferenceBeanTest(int empId, String empName) {
this.empId = empId;
this.empName = empName;
list = new ArrayList<ManagedReferenceBeanTest>();
}
public void addEmployees(ManagedReferenceBeanTest managedReferenceBeanTest) {
list.add(managedReferenceBeanTest);
}
}
输出
{
"empId" : 135,
"empName" : "Adithya Ram",
"manager" : {
"empId" : 110,
"empName" : "Sai Chaitanya"
}
}
