httpclient5 发送get请求 带参数

HttpClient5 可以通过以下步骤发送带参数的 GET 请求：

1. 创建 HttpClient 对象。

HttpClient httpClient = HttpClient.newHttpClient();

2. 创建 HttpRequest 对象，设置请求方法为 GET，设置请求 URL，设置请求参数。

String url = "http://example.com/api";
Map<String, String> params = new HashMap<>();
params.put("key1", "value1");
params.put("key2", "value2");
String query = params.entrySet().stream()
    .map(entry -> entry.getKey() + "=" + entry.getValue())
    .collect(Collectors.joining("&"));
HttpRequest httpRequest = HttpRequest.newBuilder()
    .uri(URI.create(url + "?" + query))
    .GET()
    .build();

3. 发送请求并获取响应。

HttpResponse<String> httpResponse = httpClient.send(httpRequest, HttpResponse.BodyHandlers.ofString());
String responseBody = httpResponse.body();

完整示例代码如下：

import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import java.util.HashMap;
import java.util.Map;
import java.util.stream.Collectors;

public class HttpClientExample {
    public static void main(String[] args) throws Exception {
        HttpClient httpClient = HttpClient.newHttpClient();

        String url = "http://example.com/api";
        Map<String, String> params = new HashMap<>();
        params.put("key1", "value1");
        params.put("key2", "value2");
        String query = params.entrySet().stream()
            .map(entry -> entry.getKey() + "=" + entry.getValue())
            .collect(Collectors.joining("&"));
        HttpRequest httpRequest = HttpRequest.newBuilder()
            .uri(URI.create(url + "?" + query))
            .GET()
            .build();

        HttpResponse<String> httpResponse = httpClient.send(httpRequest, HttpResponse.BodyHandlers.ofString());
        String responseBody = httpResponse.body();

        System.out.println(responseBody);
    }
}