How to use Java code to obtain city information through IP address on Baidu Maps?

How to use Java code to obtain city information through IP address on Baidu Map?

Overview:
Baidu Map provides a series of API interfaces that enable developers to obtain corresponding geographical location information based on IP addresses. This is very useful for applications that require personalized display based on the user's IP address. This article will introduce how to use Java code to achieve the function of obtaining city information through IP address.

Steps:

1. Register Baidu Map Developer Account: First, we need to go to Baidu Map Developer to register an account. After successful registration, we can create a new application in the console so that we can get a unique ak (access key). This ak will be used in subsequent requests.
2. Import necessary libraries: In Java projects, we need to import some necessary libraries for HTTP requests and JSON parsing. Here we can use the Apache HttpComponents library to make HTTP requests and the JSON-java library to parse JSON responses.
3. Write code: The following is a Java code example to obtain city information through IP address.

import org.apache.http.HttpEntity;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.json.JSONObject;

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;

public class BaiduMapAPI {
    public static void main(String[] args) {
        String ip = "IP地址"; // 需要替换成要查询的IP地址

        try {
            String ak = "你的AK"; // 需要替换成你的百度地图访问密钥

            CloseableHttpClient client = HttpClients.createDefault();
            HttpGet httpGet = new HttpGet(String.format("https://api.map.baidu.com/location/ip?ip=%s&ak=%s", ip, ak));
            CloseableHttpResponse response = client.execute(httpGet);
            HttpEntity entity = response.getEntity();

            if (entity != null) {
                InputStream inputStream = entity.getContent();
                BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));
                
                StringBuilder stringBuilder = new StringBuilder();
                String line;
                
                while ((line = reader.readLine()) != null) {
                    stringBuilder.append(line);
                }
                
                JSONObject jsonObject = new JSONObject(stringBuilder.toString());
                String city = jsonObject.getJSONObject("content").getString("address_detail").getString("city");
                
                System.out.println("城市：" + city);
            }
            
            response.close();
            client.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

Note:
In the above code, we first make an HTTP request by creating an instance of CloseableHttpClient and specify the URL to be requested. In this URL, we use the ip parameter to specify the IP address to be queried, and the ak parameter is the Baidu Map developer key.

Next, we send the HTTP request and get the response entity. If the response entity is not empty, we encapsulate it in InputStream and BufferedReader, and read the returned JSON response content line by line. We use the JSONObject class to parse the JSON response, extract the city information, and then print it out.

Finally, we close the HTTP response and HTTP client.

Summary:
This article introduces how to use Java code to obtain city information through IP address on Baidu Map. Through the interface provided by Baidu Map API, we can easily obtain the corresponding geographical location information based on the user's IP address. This is very useful for applications that require personalized display based on user location information. Hope this article is helpful to everyone.

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