JAVA发送HTTP请求的多种方式详细总结

import com.alibaba.fastjson.JSON;
import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.HashMap;
import java.util.Map;
 
public class HttpTest1 {
 
    public static void main(String[] args) {
        HttpURLConnection con = null;
 
        BufferedReader buffer = null;
        StringBuffer resultBuffer = null;
 
        try {
            URL url = new URL("http://10.30.10.151:8012/gateway.do");
            //得到连接对象
            con = (HttpURLConnection) url.openConnection();
            //设置请求类型
            con.setRequestMethod("POST");
            //设置Content-Type，此处根据实际情况确定
            con.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
            //允许写出
            con.setDoOutput(true);
            //允许读入
            con.setDoInput(true);
            //不使用缓存
            con.setUseCaches(false);
            OutputStream os = con.getOutputStream();
            Map paraMap = new HashMap();
            paraMap.put("type", "wx");
            paraMap.put("mchid", "10101");
            //组装入参
            os.write(("consumerAppId=test&serviceName=queryMerchantService&params=" + JSON.toJSONString(paraMap)).getBytes());
            //得到响应码
            int responseCode = con.getResponseCode();
            if (responseCode == HttpURLConnection.HTTP_OK) {
                //得到响应流
                InputStream inputStream = con.getInputStream();
                //将响应流转换成字符串
                resultBuffer = new StringBuffer();
                String line;
                buffer = new BufferedReader(new InputStreamReader(inputStream, "GBK"));
                while ((line = buffer.readLine()) != null) {
                    resultBuffer.append(line);
                }
                System.out.println("result:" + resultBuffer.toString());
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

<dependency>
    <groupId>commons-httpclient</groupId>
    <artifactId>commons-httpclient</artifactId>
    <version>3.1</version>
</dependency>

import com.alibaba.fastjson.JSON;
import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.methods.PostMethod;
 
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
 
public class HttpTest2 {
 
    public static void main(String[] args) {
        HttpClient httpClient = new HttpClient();
        PostMethod postMethod = new PostMethod("http://10.30.10.151:8012/gateway.do");
 
        postMethod.addRequestHeader("accept", "*
    private static String readLine(InputStream is, int contentLe) throws IOException {
        ArrayList lineByteList = new ArrayList();
        byte readByte;
        int total = 0;
        if (contentLe != 0) {
            do {
                readByte = (byte) is.read();
                lineByteList.add(Byte.valueOf(readByte));
                total++;
            } while (total < contentLe);//消息体读还未读完
        } else {
            do {
                readByte = (byte) is.read();
                lineByteList.add(Byte.valueOf(readByte));
            } while (readByte != 10);
        }
 
        byte[] tmpByteArr = new byte[lineByteList.size()];
        for (int i = 0; i < lineByteList.size(); i++) {
            tmpByteArr[i] = ((Byte) lineByteList.get(i)).byteValue();
        }
        lineByteList.clear();
 
        return new String(tmpByteArr, encoding);
    }
}

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.client.ClientHttpRequestFactory;
import org.springframework.http.client.SimpleClientHttpRequestFactory;
import org.springframework.web.client.RestTemplate;
 
@Configuration
public class RestTemplateConfig {
 
    @Bean
    public RestTemplate restTemplate(ClientHttpRequestFactory factory){
        return new RestTemplate(factory);
    }
 
    @Bean
    public ClientHttpRequestFactory simpleClientHttpRequestFactory(){
        SimpleClientHttpRequestFactory factory = new SimpleClientHttpRequestFactory();
        factory.setConnectTimeout(15000);
        factory.setReadTimeout(5000);
        return factory;
    }
}
 
 
@Autowired
RestTemplate restTemplate;
 
@Test
public void postTest() throws Exception {
    MultiValueMap<String, String> requestEntity = new LinkedMultiValueMap<>();
    Map paraMap = new HashMap();
    paraMap.put("type", "wx");
    paraMap.put("mchid", "10101");
    requestEntity.add("consumerAppId", "test");
    requestEntity.add("serviceName", "queryMerchant");
    requestEntity.add("params", JSON.toJSONString(paraMap));
    RestTemplate restTemplate = new RestTemplate();
    System.out.println(restTemplate.postForObject("http://10.30.10.151:8012/gateway.do",         requestEntity, String.class));
}