Java는 어떻게 http 요청을 시작하고 게시물을 호출하고 인터페이스를 얻습니까?

1. Java는 post 인터페이스를 호출합니다

1. URLConnection 또는 HttpURLConnection

java가 함께 제공되므로 인터페이스 응답 코드가 서버에 의해 수정되는 경우 다른 jar 패키지를 다운로드할 필요가 없습니다. , 반환을 받을 수 없습니다. 응답 코드가 올바른 경우에만 메시지를 받을 수 있습니다.

public static String sendPost(String url, String param) {
        OutputStreamWriter out = null;
        BufferedReader in = null;
        StringBuilder result = new StringBuilder("");
        try {
            URL realUrl = new URL(url);
            // 打开和URL之间的连接
            URLConnection conn = realUrl.openConnection();
            // 设置通用的请求属性
            conn.setRequestProperty("Content-Type","application/json;charset=UTF-8");
            conn.setRequestProperty("accept", "*/*");
            conn.setRequestProperty("connection", "Keep-Alive");
            conn.setRequestProperty("user-agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
            // 发送POST请求必须设置如下两行
            conn.setDoOutput(true);
            conn.setDoInput(true);
            // 获取URLConnection对象对应的输出流
            out = new OutputStreamWriter(conn.getOutputStream(), "UTF-8");
            // 发送请求参数
            out.write(param);
            // flush输出流的缓冲
            out.flush();
            // 定义BufferedReader输入流来读取URL的响应
            in = new BufferedReader(new InputStreamReader(conn.getInputStream(),"UTF-8"));
            String line;
            while ((line = in.readLine()) != null) {
                result.append(line);
            }
        } catch (Exception e) {
            System.out.println("发送 POST 请求出现异常！"+e);
            e.printStackTrace();
        }
        //使用finally块来关闭输出流、输入流
        finally{
        	if(out!=null){ try { out.close(); }catch(Exception ex){} }
        	if(in!=null){ try { in.close(); }catch(Exception ex){} }
        }
        return result.toString();
    }

HttpURLConnection 메서드 호출

//ms超时毫秒,url地址,json入参
public static String httpJson(int ms,String url,String json) throws Exception{
		String err = "00", line = null;
		StringBuilder sb = new StringBuilder();
		HttpURLConnection conn = null;
		BufferedWriter out = null;
		BufferedReader in = null;
		try{
			conn = (HttpURLConnection) (new URL(url.replaceAll("／","/"))).openConnection();
			conn.setRequestMethod("POST");
			conn.setDoOutput(true);
			conn.setDoInput(true);
			conn.setUseCaches(false);
			conn.setConnectTimeout(ms);
			conn.setReadTimeout(ms);
			conn.setRequestProperty("Content-Type","application/json;charset=utf-8");
			conn.connect();
			out = new BufferedWriter(new OutputStreamWriter(conn.getOutputStream(),"utf-8"));
			out.write(new String(json.getBytes(), "utf-8"));
			out.flush();//发送参数
			int code = conn.getResponseCode();
			if (conn.getResponseCode()==200){
				in = new BufferedReader(new InputStreamReader(conn.getInputStream(),"UTF-8"));
				while ((line=in.readLine())!=null)
					sb.append(line);
			}//接收返回值
			
		}catch(Exception ex){
			err=ex.getMessage();
		}
		try{ if (out!=null) out.close(); }catch(Exception ex){}; 
		try{ if (in!=null) in.close(); }catch(Exception ex){};
		try{ if (conn!=null) conn.disconnect();}catch(Exception ex){}
		if (!err.equals("00")) throw new Exception(err);
		return sb.toString();
	}

2. CloseableHttpClient를 사용합니다.

jar 패키지를 사용합니다.

<dependency>
    <groupId>com.alibaba.csb.sdk</groupId>
    <artifactId>http-client</artifactId>
    <version>1.1.5.1</version>
</dependency>

public static String httpPostJson(String url,String json) throws Exception{
		String data=""; 
		CloseableHttpClient httpClient = null;
		CloseableHttpResponse response = null;
		try {
			httpClient = HttpClients.createDefault();
			HttpPost httppost = new HttpPost(url);
			httppost.setHeader("Content-Type", "application/json;charset=UTF-8");
			StringEntity se = new StringEntity(json,Charset.forName("UTF-8"));
	        se.setContentType("text/json");
	        se.setContentEncoding("UTF-8");
	        httppost.setEntity(se);
	        response = httpClient.execute(httppost);
	        int code = response.getStatusLine().getStatusCode();
	        System.out.println("接口响应码:"+code);
	        data = EntityUtils.toString(response.getEntity(), "utf-8");
	        EntityUtils.consume(response.getEntity());
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			if(response!=null){ try{response.close();}catch (IOException e){} }
			if(httpClient!=null){ try{httpClient.close();}catch(IOException e){} }
		}
		return data;
	}

3.jar 패키지를 사용합니다. 두 번째 jar 패키지와 동일합니다.

public static String sendPost(){
		String result = "";
		HttpParameters.Builder builder = HttpParameters.newBuilder();
		builder.requestURL("URL") // 设置请求的URL
        		.api("api") // 设置服务名
        		.version("version") // 设置版本号
        		.method("post") // 设置调用方式, get/post
        		.accessKey("ak").secretKey("sk"); // 设置accessKey 和 设置secretKey
		// 设置请求参数（json格式)
        Map<String,String> param = new HashMap<String,String>();
        param.put("key1","value1");
        param.put("key2","value2");
        //加密，没有加密则不需要encryptParam，直接用param
        Map<String,String> encryptParam = new HashMap<String,String>();
        encryptParam.put("key3", getData(JSON.toJSONString(param)));
        ContentBody cb = new ContentBody(JSON.toJSONString(encryptParam));
        builder.contentBody(cb);
        
        try {
        	result = HttpCaller.invoke(builder.build());
		} catch (Exception e) {
			e.printStackTrace();
		}
		
        return result;
	}
	
	//自己的加密方式
	public static String getData(String data1){
		return "加密后的密文";
	}

2. Java는 get 인터페이스를 호출합니다

java

//将map型转为请求参数型
public static String getUrlData(Map<Object, Object> data) throws Exception{
	StringBuffer sb = new StringBuffer();
	try {
		Set<Map.Entry<Object, Object>> entries = data.entrySet();
		Iterator<Map.Entry<Object, Object>> iterators = entries.iterator();
		while(iterators.hasNext()){
			Map.Entry<Object, Object> next = iterators.next();
			sb.append(next.getKey().toString().trim()).append("=").append(URLEncoder.encode(next.getValue() + "", "UTF-8").trim()).append("&");
		}
		sb.deleteCharAt(sb.length() - 1);
	} catch (Exception e) {
		sb.append(e.toString());
	}
	return sb.toString();
}

//strUrl截止到?，例：http://127.0.0.1:8080/api/method?
public static String httpGet(String strUrl){
	Map<Object, Object> params = new HashMap<Object, Object>();
	params.put("key1", "value1");
	params.put("key2", "value2");
	String url=strUrl + getUrlData(params);
	
  	StringBuilder result = new StringBuilder();
    BufferedReader in = null;
    try {
        URL realUrl = new URL(url);
        // 打开和URL之间的连接
        URLConnection connection = realUrl.openConnection();
        // 设置通用的请求属性
        connection.setRequestProperty("accept", "*/*");
        connection.setRequestProperty("connection", "Keep-Alive");
        connection.setRequestProperty("user-agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
        // 建立实际的连接
        connection.connect();
        // 获取所有响应头字段
        // 定义 BufferedReader输入流来读取URL的响应
        in = new BufferedReader(new InputStreamReader(connection.getInputStream(),"UTF-8"));
        String line;
        while ((line = in.readLine()) != null) {
            result.append(line);
        }
    } catch (Exception e) {
        System.out.println("发送GET请求出现异常！" + e);
        e.printStackTrace();
    }
    finally {
    	if (in != null){ try { in.close(); }catch(Exception e2){} }
    }
    return result.toString();
}

와 함께 제공되는 URLConnection을 사용하세요.

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