与此类似的内容应该为您的json示例提供必要的对象：

package com.example;
import java.util.List;
import com.google.gson.annotations.Expose;
import com.google.gson.annotations.SerializedName;
public class CountyContainer {
 @SerializedName("county")
 @Expose
 private String county;
 @SerializedName("houses")
 @Expose
 private List<House> houses = null;
 public String getCounty() {
  return county;
 }
 public void setCounty(String county) {
  this.county = county;
 }
 public List<House> getHouses() {
  return houses;
 }
 public void setHouses(List<House> houses) {
  this.houses = houses;
 }
}

package com.example;
import com.google.gson.annotations.Expose;
import com.google.gson.annotations.SerializedName;
public class House {
 @SerializedName("squareFeet")
 @Expose
 private Integer squareFeet;
 @SerializedName("bedrooms")
 @Expose
 private Integer bedrooms;
 @SerializedName("bathrooms")
 @Expose
 private Integer bathrooms;
 @SerializedName("internet")
 @Expose
 private String internet;
 @SerializedName("location")
 @Expose
 private String location;
 public Integer getSquareFeet() {
  return squareFeet;
 }
 public void setSquareFeet(Integer squareFeet) {
  this.squareFeet = squareFeet;
 }
 public Integer getBedrooms() {
  return bedrooms;
 }
 public void setBedrooms(Integer bedrooms) {
  this.bedrooms = bedrooms;
 }
 public Integer getBathrooms() {
  return bathrooms;
 }
 public void setBathrooms(Integer bathrooms) {
  this.bathrooms = bathrooms;
 }
 public String getInternet() {
  return internet;
 }
 public void setInternet(String internet) {
  this.internet = internet;
 }
 public String getLocation() {
  return location;
 }
 public void setLocation(String location) {
  this.location = location;
 }
}

您可以使用此在线服务并选择gson注解样式自行生成这些注解：
http://www.jsonschema2pojo.org/
创建对象后，可以使用以下命令将这些对象写入json文件：

final Gson gson = new Gson();
try (final FileWriter writer = new FileWriter("houses.json")) {
 gson.toJson(houses, writer); // houses refers to your object containing the List of House objects and the country
} catch (final IOException e) {
 // Handle exceptions here
}

或者，您也可以使用将json数据放入 String :

String json = gson.toJson(houses);

有关gson功能的更多信息，请查看官方文档：
https://www.javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/module-summary.html

根本没有 House 提供课程，但我想我们可以跳过。你正朝着正确的方向前进。只需添加另一个类：

public class County {
    private String county;
    private List<House> houses;
    // getters, setters, whatever :) 
}

并创建该类的示例。设置name（county字段）和houses并序列化为json:）
我可能会将json数组重命名为 JSONArray counties = new JSONArray(); 您需要添加到这个数组中的是一个名为“jefferson”的县和您现在拥有的房屋列表。

County county = new County();
county.setCounty("Jefferson");
List<House> houses = new ArrayList<>();
houses.add(houseOne);
houses.add(houseTwo);
county.setHouses(houses);
counties.add(county);

这可能不是100%工作的代码，但希望想法很清楚：）