content: package com.alibaba.json.bvt.issue_1800;
  
  import com.alibaba.fastjson.JSON;
  import com.alibaba.fastjson.annotation.JSONField;
  import com.alibaba.fastjson.serializer.SerializerFeature;
  import junit.framework.TestCase;
  
  import java.util.HashMap;
  import java.util.LinkedHashMap;
  import java.util.Map;
  
  public class Issue1871 extends TestCase  {
      public void test_for_issue() throws Exception {
          UnwrapClass m = new UnwrapClass();
          m.map = new HashMap();
          m.name = "ljw";
          m.map.put("a", "1");
          m.map.put("b", "2");
  
          String json = JSON.toJSONString(m, SerializerFeature.WriteClassName);
          System.out.println(json);
      }
  
      public static class UnwrapClass {
  
          private String name;
  
          @JSONField(unwrapped = true)
          private Map<String, String> map;
  
          public String getName() {
              return name;
          }
  
          public void setName(String name) {
              this.name = name;
          }
  
          public Map<String, String> getMap() {
              return map;
          }
  
          public void setMap(Map<String, String> map) {
              this.map = map;
          }
      }
  }
  