java -jar 发送请求

java -jar命令本身并不能发送网络请求，它只是用于运行Java应用程序。如果你想发送网络请求，通常需要在Java应用程序中使用相关的网络库或框架，例如java.net或Apache HttpClient等。这些库可以让你通过HTTP、TCP、UDP等协议发送请求，并接收响应。具体的使用方法和代码实现，可以参考相关的文档和示例。

相关问题

java 引用jar包发送请求

要使用Java引用jar包发送HTTP请求，可以使用Java标准库中的HttpURLConnection类或者第三方库如Apache HttpComponents或OkHttp。

以下是使用HttpURLConnection类发送HTTP GET请求的示例代码：

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

public class HttpGetRequest {
    public static void main(String[] args) {
        try {
            URL url = new URL("http://example.com");
            HttpURLConnection con = (HttpURLConnection) url.openConnection();
            con.setRequestMethod("GET");
            int status = con.getResponseCode();
            BufferedReader in = new BufferedReader(new InputStreamReader(con.getInputStream()));
            String inputLine;
            StringBuffer content = new StringBuffer();
            while ((inputLine = in.readLine()) != null) {
                content.append(inputLine);
            }
            in.close();
            System.out.println(content.toString());
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

以下是使用Apache HttpComponents发送HTTP POST请求的示例代码：

import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.HttpClientBuilder;
import java.io.BufferedReader;
import java.io.InputStreamReader;

public class HttpPostRequest {
    public static void main(String[] args) {
        try {
            String url = "http://example.com/api";
            HttpClient client = HttpClientBuilder.create().build();
            HttpPost post = new HttpPost(url);
            StringEntity input = new StringEntity("{\"key\":\"value\"}");
            input.setContentType("application/json");
            post.setEntity(input);
            HttpResponse response = client.execute(post);
            BufferedReader rd = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
            StringBuffer result = new StringBuffer();
            String line = "";
            while ((line = rd.readLine()) != null) {
                result.append(line);
            }
            System.out.println(result.toString());
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

以上示例代码仅供参考，实际使用时需要根据具体需要进行修改。

java httpclient发送请求

Java HttpClient是一个发送HTTP请求的开源库，可以用来发送GET、POST等请求。下面是使用HttpClient发送POST请求的示例代码：

import org.apache.http.HttpEntity;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;

public class HttpClientExample {
    public static void main(String[] args) {
        CloseableHttpClient httpClient = HttpClients.createDefault();
        try {
            HttpPost httpPost = new HttpPost("http://example.com/api/endpoint");
            httpPost.addHeader("Content-Type", "application/json");
            
            String jsonData = "{\"key1\":\"value1\", \"key2\":\"value2\"}";
            StringEntity entity = new StringEntity(jsonData);
            httpPost.setEntity(entity);
            
            CloseableHttpResponse response = httpClient.execute(httpPost);
            try {
                HttpEntity responseEntity = response.getEntity();
                String responseBody = EntityUtils.toString(responseEntity);
                System.out.println(responseBody);
            } finally {
                response.close();
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                httpClient.close();
            } catch (Exception e) {
                e.printStackTrace();            }
        }
    }
}

以上代码使用了Apache HttpClient库，它需要引入相关的jar包。首先创建一个CloseableHttpClient对象，然后创建一个HttpPost对象，并设置请求URL和请求头部信息。接着创建一个StringEntity对象，将请求参数转化为JSON格式，并将其设置为HttpPost的实体。最后执行HttpPost请求，获取响应实体，将其转化为字符串并打印出来。最后关闭HttpClient。