有没有办法使用 Jackson 将 Map 转换为 JSON 表示而不写入文件

I'm trying to use Jackson to convert a HashMap to a JSON representation.

然而，我看到的所有方法都涉及到写入文件，然后读回它，这似乎真的很低效.我在想，有没有什么办法可以直接做呢？

Here's an example of an instance where I'd like to do it

public static Party readOneParty(String partyName) {
  Party localParty = new Party();
  if(connection==null) {
    connection = new DBConnection();
  } try {
    String query = "SELECT * FROM PureServlet WHERE PARTY_NAME=?";
    ps = con.prepareStatement(query);
    ps.setString(1, partyName);
    resultSet = ps.executeQuery();
    meta = resultSet.getMetaData();
    String columnName, value;
    resultSet.next();
    for(int j=1;j<=meta.getColumnCount();j++) { // necessary to start at j=1 because of MySQL index starting at 1
      columnName = meta.getColumnLabel(j);
      value = resultSet.getString(columnName);
      localParty.getPartyInfo().put(columnName, value); // this is the hashmap within the party that keeps track of the individual values. The column Name = label, value is the value
    }
  }
}

public class Party {

  HashMap <String,String> partyInfo = new HashMap<String,String>();

  public HashMap<String,String> getPartyInfo() throws Exception {
    return partyInfo;
  }
}

输出结果如下所示

"partyInfo": {
  "PARTY_NAME": "VSN",
  "PARTY_ID": "92716518",
  "PARTY_NUMBER": "92716518"
}

到目前为止，我遇到的每一个使用ObjectMapper的例子都涉及到写入一个文件，然后将其读回.

是否有Java的HashMap或Map的Jackson版本可以以与我实现的类似的方式工作？