Java发起Http请求

ゝ一纸荒年。 2023-06-22 13:40 25阅读 0赞

# Java发起Http请求 #

*  **首先引入pom文件**

<dependency>
                <groupId>org.apache.httpcomponents</groupId>
                <artifactId>httpclient</artifactId>
                <version>4.5.5</version>
            </dependency>
            <dependency>
                <groupId>commons-httpclient</groupId>
                <artifactId>commons-httpclient</artifactId>
                <version>3.1</version>
            </dependency>

*  **编写工具类（HttpUtils）**

public class HttpUtils { 
    
        public String getUrl(String url, Map<String, String> paramsMap) throws Exception { 
            url = url.trim();
            if (paramsMap != null && !paramsMap.isEmpty()) { 
                if (!url.contains("?")) { 
                    url += "?";
                }
                StringBuilder urlBuilder = new StringBuilder(url);
                for (String key : paramsMap.keySet()) { 
                    urlBuilder.append(key).append("=").append(paramsMap.get(key)).append("&");
                }
                url = urlBuilder.toString();
            }
            if ("&".equals(url.substring(url.length() - 1))) { 
                return getUrl(url.substring(0, url.length() - 1));
            }
            return getUrl(url);
        }
    
        public String getUrl(String url) throws Exception { 
            GetMethod getMethod = new GetMethod(URIUtil.encodeQuery(url));
            getMethod.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
    
            HttpClient client = new HttpClient();
            int statusCode = client.executeMethod(getMethod);
            if (statusCode != HttpStatus.SC_OK) { 
                System.err.println("Method failed: " + getMethod.getStatusLine());
            }
            //从请求返回体获得编码格式
            String responseCharSet = getMethod.getResponseCharSet();
    
            // 读取内容
            BufferedReader bufferedInputStream = new BufferedReader(new InputStreamReader(getMethod.getResponseBodyAsStream(), responseCharSet));
            // 处理内容
            StringBuilder stringBuffer = new StringBuilder();
            String str;
            while ((str = bufferedInputStream.readLine()) != null) { 
                stringBuffer.append(str);
            }
            return stringBuffer.toString();
        }
    
    
        public String postUrl(String url, Map<String, String> paramsMap) throws IOException { 
            PostMethod postMethod = new PostMethod(url);
            postMethod.getParams().setParameter(HttpMethodParams.HTTP_CONTENT_CHARSET, "UTF-8");
            if (paramsMap == null || paramsMap.isEmpty()) { 
                paramsMap = new HashMap<>();
            }
            for (String key : paramsMap.keySet()) { 
                postMethod.addParameter(key, MapUtils.getString(paramsMap, key));
            }
            HttpClient httpClient = new HttpClient();
            int statusCode = httpClient.executeMethod(postMethod);
            if (statusCode != HttpStatus.SC_OK) { 
                return null;
            }
            // 读取内容
            BufferedReader bufferedInputStream = new BufferedReader(new InputStreamReader(postMethod.getResponseBodyAsStream()));
            // 处理内容
            StringBuilder stringBuffer = new StringBuilder();
            String str;
            while ((str = bufferedInputStream.readLine()) != null) { 
                stringBuffer.append(str);
            }
            return stringBuffer.toString();
        }
    
        public String postUrl(String url, String body) { 
            try { 
                PostMethod postMethod = new PostMethod(url);
                RequestEntity requestEntity = new StringRequestEntity(body, "application/json", "UTF-8");
                postMethod.setRequestEntity(requestEntity);
                HttpClient httpClient = new HttpClient();
            int statusCode = httpClient.executeMethod(postMethod);
            if (statusCode != HttpStatus.SC_OK) { 
                return null;
            }
            // 读取内容
            BufferedReader bufferedInputStream = new BufferedReader(new InputStreamReader(postMethod.getResponseBodyAsStream()));
            // 处理内容
            StringBuilder stringBuffer = new StringBuilder();
            String str;
            while ((str = bufferedInputStream.readLine()) != null) { 
                stringBuffer.append(str);
            }
                return stringBuffer.toString();
            } catch (IOException e) { 
                e.printStackTrace();
            }
            return null;
        }
    
    }

*  **示例（Get）**

//请求
    		@GetMapping("/http/{id}")
    	    public void testGetHttp(@PathVariable("id") String id, @ModelAttribute TestGetBody testGetBody) { 
    
      		}
    
    		//发起请求
    		HashMap<String, String> param = new HashMap<>();
            param.put("name", "张三");
            param.put("age", "23");
            String url = httpUtils.getUrl("http://IP:端口/http/123456", param);
            //或
            String url = httpUtils.getUrl("http://IP:端口/http/123456?name=张三&age=23");

*  **for循环N输入N.for即可**

//请求
    	@PostMapping("/http")
        public void testPostHttp(@RequestBody TestGetBody testGetBody) { 
        
        }
    	
    	//发起请求
    	String body = "{\"name\":\"张三\",\"age\":1}";
        String url = httpUtils.postUrl("http://IP:端口/http", body);

//请求
    	@PostMapping("/http")
        public void testPostHttp(@RequestParam("name") String name,
                                 @RequestParam("age") Integer age) { 
    
        }
    	
    	//发起请求
    	HashMap<String, String> param = new HashMap<>();
        param.put("name", "张三");
        param.put("age", "23");
        String url = httpUtils.postUrl("http://IP:端口/http", param);