映射替换了列表对象的所有相同键值

Question

我试图从bean列表中替换仅选定索引的地图详细信息,但它替换了包含相同键的每个列表对象的所有值.如果我在创建新值之前创建新的map对象,那么它工作正常,但我想知道下面的代码行为异常的原因.

public static void main(String[] args) {

    List<PolicyAddlnInsuredBean> lst = new ArrayList<PolicyAddlnInsuredBean>();
    PolicyAddlnInsuredBean pb = new PolicyAddlnInsuredBean();
    Map<String, Map<String, Object>> epInfoMap = new HashMap<String, Map<String,Object>>();

    Map<String,Object> map = new HashMap<String, Object>();
    map.put("addtlnInsReqd", "YES");
    map.put("selectedFlg", "No");
    epInfoMap.put("AL", map);
    pb.setEpInfoMap(epInfoMap);
    lst.add(pb);

    epInfoMap = new HashMap<String, Map<String,Object>>();
    map = new HashMap<String, Object>();
    map.put("addtlnInsReqd", "YES");
    map.put("selectedFlg", "No");
    epInfoMap.put("AL", map);
    pb.setEpInfoMap(epInfoMap);
    lst.add(pb);

    lst.get(0).getEpInfoMap().get("AL").put("selectedFlg", "Yes");
    System.out.println(lst);
}

我的Pojo课程:

public class PolicyAddlnInsuredBean{

  private Map<String,Map<String,Object>> epInfoMap =new HashMap<String, Map<String,Object>>(); 

  public Map<String, Map<String, Object>> getEpInfoMap() {
    return epInfoMap;
  }
  public void setEpInfoMap(Map<String, Map<String, Object>> epInfoMap) {
    this.epInfoMap = epInfoMap;
  }
  @Override
  public String toString() {
      return "PolicyAddlnInsuredBean [epInfoMap=" + epInfoMap + "]";
  }

}

Answer 1

只有一个pb对象,添加两次lst(原理:"检查news").