content: package com.alibaba.fastjson2.issues_2800;
  
  import com.alibaba.fastjson2.JSON;
  import com.alibaba.fastjson2.JSONWriter;
  import com.alibaba.fastjson2.annotation.JSONField;
  import org.junit.jupiter.api.Test;
  
  import static org.junit.jupiter.api.Assertions.assertEquals;
  
  public class Issue2820 {
      static class CityGMLVersionMixin {
          @JSONField(value = true)
          public String toValue() {
              return null;
          }
      }
  
      @Test
      public void test() {
          JSON.mixIn(CityGMLVersion.class, CityGMLVersionMixin.class);
          FOO foo = JSON.parseObject("{\n" +
                  "  \"version\": \"2.0\"\n" +
                  "}", FOO.class);
  
          assertEquals(CityGMLVersion.v2_0, foo.getVersion());
      }
  
      public class FOO {
          @JSONField(serializeFeatures = JSONWriter.Feature.WriteEnumUsingToString)
          private CityGMLVersion version;
  
          public CityGMLVersion getVersion() {
              return version;
          }
  
          public FOO setVersion(CityGMLVersion version) {
              this.version = version;
              return this;
          }
  
          public FOO setVersion(String version) {
              this.version = CityGMLVersion.fromValue(version);
              return this;
          }
      }
  
      public enum CityGMLVersion {
          v3_0("3.0"),
          v2_0("2.0"),
          v1_0("1.0");
  
          private final String value;
  
          CityGMLVersion(String value) {
              this.value = value;
          }
  
          public String toValue() {
              return this.value;
          }
  
          public static CityGMLVersion fromValue(String value) {
              for (CityGMLVersion v : values()) {
                  if (v.value.equals(value)) {
                      return v;
                  }
              }
              return null;
          }
  
          public String toString() {
              return this.value;
          }
      }
  
      public enum CityGMLVersion1 {
          v3_0("3.0"),
          v2_0("2.0"),
          v1_0("1.0");
  
          private final String value;
  
          CityGMLVersion1(String value) {
              this.value = value;
          }
  
          public String toValue() {
              return this.value;
          }
  
          public static CityGMLVersion1 fromValue(String value) {
              for (CityGMLVersion1 v : values()) {
                  if (v.value.equals(value)) {
                      return v;
                  }
              }
              return null;
          }
  
          public String toString() {
              return this.value;
          }
      }
  
      @Test
      public void test1() {
          Foo1 foo = JSON.parseObject("{\n" +
                  "  \"version\": \"2.0\"\n" +
                  "}", Foo1.class);
  
          assertEquals(CityGMLVersion1.v2_0, foo.version);
      }
  
      public static class Foo1 {
          public CityGMLVersion1 version;
      }
  }
  