JAVA中使用HTTPclient访问url取得数据

忘是亡心i 2022-05-27 05:49 199阅读 0赞

**使用GET方法获取数据：**

/** * 根据URL试用get方法取得返回的数据 * @param url * URL地址，参数直接挂在URL后面即可 * @return */  
    public static String getGetDateByUrl(String url){  
    
        String data = null;  
        //构造HttpClient的实例 
        HttpClient httpClient = new HttpClient();    
        //创建GET方法的实例 
        GetMethod getMethod = new GetMethod(url);   
        //设置头信息：如果不设置User-Agent可能会报405，导致取不到数据 
        getMethod.setRequestHeader("User-Agent", "Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:39.0) Gecko/20100101 Firefox/39.0");  
        //使用系统提供的默认的恢复策略 
        getMethod.getParams().setParameter(HttpMethodParams.RETRY_HANDLER, new DefaultHttpMethodRetryHandler());    
        try{  
            //开始执行getMethod 
            int statusCode = httpClient.executeMethod(getMethod);  
            if (statusCode != HttpStatus.SC_OK) {  
                System.err.println("Method failed:" + getMethod.getStatusLine());  
            }  
            //读取内容 
            byte[] responseBody = getMethod.getResponseBody();  
            //处理内容 
            data = new String(responseBody);  
        }catch (HttpException e){  
            //发生异常，可能是协议不对或者返回的内容有问题 
            System.out.println("Please check your provided http address!");  
            data = "";  
            e.printStackTrace();  
        }catch(IOException e){  
            //发生网络异常 
            data = "";  
            e.printStackTrace();  
        }finally{  
            //释放连接 
            getMethod.releaseConnection();  
        }  
        return data;  
    }

**使用POST方法取得数据 ：**

/** * 根据post方法取得返回数据 * @param url * URL地址 * @param array * 需要以post形式提交的参数 * @return */  
    public static String getPostDateByUrl(String url,Map<String ,String> array){  
        String data = null;  
        //构造HttpClient的实例 
        HttpClient httpClient = new HttpClient();    
        //创建post方法的实例 
        PostMethod postMethod = new PostMethod(url);   
        //设置头信息 
        postMethod.setRequestHeader("User-Agent", "Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:39.0) Gecko/20100101 Firefox/39.0");  
        postMethod.addRequestHeader("Content-Type", "application/x-www-form-urlencoded;charset=utf-8");  
        //遍历设置要提交的参数 
        Iterator it = array.entrySet().iterator();    
        while (it.hasNext()){  
            Map.Entry<String,String> entry =(Map.Entry) it.next();    
            String key = entry.getKey();    
            String value = entry.getValue().trim();    
            postMethod.setParameter(key,value);  
        }  
        //使用系统提供的默认的恢复策略 
        postMethod.getParams().setParameter(HttpMethodParams.RETRY_HANDLER, new DefaultHttpMethodRetryHandler());    
        try{  
            //执行postMethod 
            int statusCode = httpClient.executeMethod(postMethod);  
            if (statusCode != HttpStatus.SC_OK) {  
                System.err.println("Method failed:" + postMethod.getStatusLine());  
            }  
            //读取内容 
            byte[] responseBody = postMethod.getResponseBody();  
            //处理内容 
            data = new String(responseBody);  
        }catch (HttpException e){  
            //发生致命的异常，可能是协议不对或者返回的内容有问题 
            System.out.println("Please check your provided http address!");  
            data = "";  
            e.printStackTrace();  
        }catch(IOException e){  
            //发生网络异常 
            data = "";  
            e.printStackTrace();  
        }finally{  
            //释放连接 
            postMethod.releaseConnection();  
        }  
        System.out.println(data);  
        return data;  
    }