java写一个get请求 携带参数工具类 并往请求头里添加key值

在Java中，你可以创建一个工具类来简化GET请求的过程，同时携带参数并设置请求头。这里是一个简单的示例，我们将使用HttpURLConnection来进行HTTP请求：

首先，定义一个工具类，比如`RestRequestUtils.java`：

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;

public class RestRequestUtils {

    public static String get(String url, Map<String, String> params, String apiKey) throws Exception {
        StringBuilder query = new StringBuilder();
        for (Map.Entry<String, String> entry : params.entrySet()) {
            if (query.length() > 0) {
                query.append("&");
            }
            query.append(entry.getKey()).append("=").append(entry.getValue());
        }

        // URL with parameters
        URL obj = new URL(url + "?" + query.toString());

        // Adding request header
        HttpURLConnection con = (HttpURLConnection) obj.openConnection();
        con.setRequestMethod("GET");
        con.setRequestProperty("Authorization", "Bearer " + apiKey); // Assuming 'Bearer' is the key for your API key

        int responseCode = con.getResponseCode();
        if (responseCode == HttpURLConnection.HTTP_OK) {
            BufferedReader in = new BufferedReader(new InputStreamReader(con.getInputStream()));
            String inputLine;
            StringBuffer response = new StringBuffer();

            while ((inputLine = in.readLine()) != null) {
                response.append(inputLine);
            }
            in.close();
            return response.toString();
        } else {
            throw new RuntimeException("Failed : HTTP error code : " + responseCode);
        }
    }
}

在这个例子中，我们首先将传递的参数转换为URL查询字符串，然后通过`HttpURLConnection`发送GET请求，并在请求头中添加API密钥。如果服务器返回状态码为200（HTTP_OK），则读取响应内容并返回。

使用这个工具类的样例：

import java.util.HashMap;
import java.util.Map;

public class Main {
    public static void main(String[] args) {
        try {
            Map<String, String> params = new HashMap<>();
            params.put("param1", "value1");
            params.put("param2", "value2");

            String apiKey = "your_api_key_here";
            String result = RestRequestUtils.get("http://example.com/api", params, apiKey);
            System.out.println(result);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}