Java Operation Guide: Detailed explanation of route traffic situation query function of Amap API

Java Operation Guide: Detailed explanation of the route traffic situation query function of Amap API

Introduction:
With the continuous development of urban transportation, our demand for real-time traffic conditions is becoming more and more important. As an excellent geographical information service platform, Amap provides a rich map API interface, including route and traffic situation query functions. This article will introduce in detail how to use Java language to operate the Amap API, and combine it with code examples to demonstrate the specific implementation of route traffic situation query.

1. Register and obtain the Key of Amap API
Before we begin, we need to register the Key of Amap API first. After successful registration, you will get a unique Key, which we need to use in the code to make interface calls.

2. Import related dependency packages
To use the Amap API in a Java project, you first need to import the relevant dependency packages. Add the following dependencies in the project's pom.xml file:

<dependency>
   <groupId>com.alibaba</groupId>
   <artifactId>fastjson</artifactId>
   <version>1.2.62</version>
</dependency>
<dependency>
   <groupId>com.squareup.okhttp3</groupId>
   <artifactId>okhttp</artifactId>
   <version>3.12.0</version>
</dependency>

3. Send route traffic situation query request
First, we need to create a Java class for sending route traffic situation query requests. The code example is as follows:

import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.Response;

import java.io.IOException;
import java.util.Objects;

public class TrafficRouteQuery {
    private static final String API_KEY = "your_api_key";

    // 请求URL
    private static final String API_URL = "https://restapi.amap.com/v3/traffic/status/rectangle";

    public static void main(String[] args) {
        OkHttpClient client = new OkHttpClient();

        String rectangle = "116.351147,39.966309;116.357134,39.968727";
        String url = API_URL + "?key=" + API_KEY + "&rectangle=" + rectangle;

        Request request = new Request.Builder()
                .url(url)
                .build();

        try {
            Response response = client.newCall(request).execute();
            String responseBody = Objects.requireNonNull(response.body()).string();
            System.out.println(responseBody);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

In the above code, first we define a API_KEY constant to store the Key of your Amap API. Next, we defined a API_URL constant to store the URL for route traffic situation query. In the main method, we use OkHttpClient to send HTTP requests and obtain traffic situation query results.

4. Analyze the results of the traffic situation query
Next, we need to analyze the results of the traffic situation query. In the above code, we directly output the query results to the console. In order to better view the results, we can use fastjson to parse JSON data. The sample code is as follows:

import com.alibaba.fastjson.JSONArray;
import com.alibaba.fastjson.JSONObject;

public class TrafficRouteQuery {
    // ... 上述代码省略 ...

    public static void main(String[] args) {
        // ... 上述代码省略 ...

        try {
            // 发送请求并获取响应
            Response response = client.newCall(request).execute();
            String responseBody = Objects.requireNonNull(response.body()).string();

            // 解析JSON数据
            JSONObject json = JSONObject.parseObject(responseBody);
            JSONArray roads = json.getJSONArray("road");

            // 遍历交通态势查询结果
            for (int i = 0; i < roads.size(); i++) {
                JSONObject road = roads.getJSONObject(i);
                String name = road.getString("name");
                int status = road.getIntValue("status");
                System.out.println("道路名称：" + name);
                System.out.println("交通状态：" + getStatusText(status));
                System.out.println();
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    private static String getStatusText(int status) {
        switch (status) {
            case 1:
                return "畅通";
            case 2:
                return "缓行";
            case 3:
                return "拥堵";
            case 4:
                return "严重拥堵";
            default:
                return "未知";
        }
    }
}

In the above code, we first use fastjson to format the JSON The query results are parsed into JSONObject objects. Next, we obtain the corresponding field values ​​from the JSONObject object, including road name and traffic status. Finally, we use the getStatusText method to convert the numeric representation of the traffic status into a text representation.

Summary:
Through the introduction of this article, we have learned how to use the Java language to operate the route and traffic situation query function of the Amap API. We first log in to the AMAP open platform to register to obtain the API key, and import the relevant dependency packages. Then, we obtain the results of the traffic situation query by sending an HTTP request, and use fastjson to parse the JSON data to parse and display the query results. I hope this article can provide you with some reference and guidance on operating the Amap API in Java.

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