解析从 Google Distance Matrix API 发送的 Json 响应

Question

当目的地或始发地在英国境外时，就会发生此 json，因此不会给我任何结果！我需要检查此空检查，这样我就不会收到空指针异常

JSON 结果：

{
"destination_addresses" : [ "Durham, NC, USA" ],
"origin_addresses" : [ "Lancashire, UK" ],
"rows" : [
  {
     "elements" : [
        {
           "status" : "ZERO_RESULTS"
        }
     ]
  }
],

"状态" ： "正常" }

法典：

public static void extractJsonFromRequest(GoogleResponsePojo response) {
    String destinationAddress = 
    response.getDestination_addresses().get(0);
    String timeTaken = 
response.getRows().get(0).getElements().get(0).getDuration().getText();
    String originAddress = response.getOrigin_addresses().get(0);
    System.out.println("It will take ** "+  timeTaken + " ** to walk 
from " + originAddress + " to " + destinationAddress);
}

Google Reponse POJO，它是json的结构：

public class GoogleResponsePojo {
private List<String> destination_addresses;
private List<String> origin_addresses;
private List<Rows> rows;
public List<String> getDestination_addresses() {
    return destination_addresses;
}
public void setDestination_addresses(List<String> destination_addresses) {
    this.destination_addresses = destination_addresses;
}
public List<String> getOrigin_addresses() {
    return origin_addresses;
}
public void setOrigin_addresses(List<String> origin_addresses) {
    this.origin_addresses = origin_addresses;
}
public List<Rows> getRows() {
    return rows;
}
public void setRows(List<Rows> rows) {
    this.rows = rows;
}
}
class Rows {
private List<Element> elements;
public List<Element> getElements() {
    return elements;
}
public void setElements(List<Element> elements) {
    this.elements = elements;
}
}
class Element {
private TextValue distance;
private TextValue duration;
public TextValue getDistance() {
    return distance;
}
public void setDistance(TextValue distance) {
    this.distance = distance;
}
public TextValue getDuration() {
    return duration;
}
public void setDuration(TextValue duration) {
    this.duration = duration;
}
}
class TextValue {
private String text;
private  String value;
public String getText() {
    return text;
}
public void setText(String text) {
    this.text = text;
}
public String getValue() {
    return value;
}
public void setValue(String value) {
    this.value = value;
}
}

我

基本上只需要解析下面的 json，这样我就可以说（如果状态 ！= ZERO_RESULTS）保存响应，否则会引发异常！可能很容易，但我在挣扎！非常感谢！

Answer 1

将 GoogleResponsePojo 更改为：

 public class GoogleResponsePojo {
    private List<String> destination_addresses;
    private List<String> origin_addresses;
    private List<Rows> rows;
    public void setDestination_addresses(List<String> destination_addresses) {
        this.destination_addresses = destination_addresses;
    }
    public void setOrigin_addresses(List<String> origin_addresses) {
        this.origin_addresses = origin_addresses;
    }
    public void setRows(List<Rows> rows) {
        this.rows = rows;
    }
    //getters
}

private static class Rows{
    private List<Element> elements;
    public void setElements(List<Element> elements) {
        this.elements = elements;
    }
    //getters
}
private static class Element{
    private TextValue distance;
    private TextValue duration;
    public void setDistance(TextValue distance) {
        this.distance = distance;
    }
    public void setDuration(TextValue duration) {
        this.duration = duration;
    }
    //getters
}
private static class TextValue{
    private String text;
    private  String value;
    public void setText(String text) {
        this.text = text;
    }
    public void setValue(String value) {
        this.value = value;
    }
    //getters
}

您可以按如下方式duration：

GoogleResponsePojo name = gson.fromJson(response.toString(),GoogleResponsePojo.class);
name.getRows().get(0).getDuration().getText();

我建议使用基于apache http api构建的http-request。它使用简单：

 public static final String BASE_URL = "https://maps.googleapis.com/maps/api/distancematrix/json";
private static final HttpRequest<GoogleResponsePojo> HTTP_REQUEST =
        HttpRequestBuilder.createGet(BASE_URL, GoogleResponsePojo.class)
                .addDefaultRequestParameter("origins", "Seattle")
                .addDefaultRequestParameter("destinations", "San+Francisco")
                .addDefaultRequestParameter("key", "***")
                .build();
@GET
@Produces(MediaType.APPLICATION_JSON)
public static void updateTestExecutionDetails() throws IOException {
    ResponseHandler<GoogleResponsePojo> responseHandler = HTTP_REQUEST.execute();
    GoogleResponsePojo name = responseHandler.orElseThrow(); // throws ResponseException when status code != 200
    System.out.println(name.getDestination_addresses().get(0));
    System.out.println(name.getRows().get(0).getElements().get(0).getDuration().getText());
    System.out.println(name.getOrigin_addresses().get(0));
}