解析從Google Distance Matrix API發送的Json響應

Question

當目的地或起點不在英國之外時，會出現此json，因此不會給我任何結果！ 我需要檢查是否為空檢查，這樣我就不會收到空指針異常

JSON結果：

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

“狀態”：“確定”}

碼：

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是json的結構：

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;
}
}

我本質上只需要解析下面的json，以便我可以說（如果status！= ZERO_RESULTS）保存響應，否則拋出異常！ 可能很簡單，但我很掙扎！ 非常感謝！

Answer 1

將GoogleResponsePojo更改為：

 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
}

您可以按照以下方式進行duration ：

GoogleResponsePojo name = gson.fromJson(response.toString(),GoogleResponsePojo.class);

name.getRows().get(0).getDuration().getText();

我建議使用基於apache http api構建的http-request 。 使用簡單：

 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));
}