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java如何發起http請求呼叫post與get接口

WBOY
發布: 2023-05-16 19:53:29
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    一、java呼叫post介面

    1、使用URLConnection或HttpURLConnection

    java自帶的,無須下載其他jar套件

    URLConnection方式調用,如果介面回應碼被服務端修改則無法接收到返回封包,只能當回應碼正確時才能接收到返回

    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();
        }
    登入後複製

    HttpURLConnection方式呼叫

    #
    //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();
    	}
    登入後複製

    2、使用CloseableHttpClient

    使用的jar包

    <dependency>
        <groupId>com.alibaba.csb.sdk</groupId>
        <artifactId>http-client</artifactId>
        <version>1.1.5.1</version>
    </dependency>
    登入後複製
    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;
    	}
    登入後複製

    3、使用HttpCaller

    使用的jar包同第2個中的jar包。

    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";
    	}
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    二、java呼叫get介面

    使用java自帶的URLConnection

    //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();
    }
    登入後複製

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