一、Jsoup查找DOM元素的方法

　　getElementById(String id) 根據id 來查詢DOM

　　getElementsByTag(String tagName) 根據tag 名稱來查詢DOM

　　getElementsByClass(String className) 根據樣式名稱來查詢DOM

　　getElementsByAttribute(String key) 根據屬性名來查詢DOM

　　getElementsByAttributeValue(String key,String value) 根據屬性名和屬性值來查詢DOM

二、代碼實現

    public
 
 static void main(String[] args) throws Exception{
        // 創建httpClient實例
        CloseableHttpClient httpClient = HttpClients.createDefault();
        // 創建httpGet實例
        HttpGet httpGet = new HttpGet("http://www.cnblogs.com");
        httpGet.setHeader("User-Agent", "Mozilla/5.0 (Windows NT 6.1; WOW64; rv:45.0) Gecko/20100101 Firefox/45.0");
        CloseableHttpResponse response 
 
= httpClient.execute(httpGet);
        String content = null;
        if(response != null){
            HttpEntity entity = response.getEntity();   
            content = EntityUtils.toString(entity, "UTF-8");  // 獲取網頁內容
            
            Document document = Jsoup.parse(content);  // 解析網頁，得到文檔對象
 

            
            /**
             * 1.根據tag獲取元素
             */
            Elements elements = document.getElementsByTag("title"); // 獲取 tag為 title的DOM元素
            Element element = elements.get(0); // 獲取第一個DOM元素
            String title = element.text();  // 返回元素的文本
            System.out.println("博客園的標題：" + title);
            
            /**
             * 2.根據 id獲取元素
             */
            Element element2 = document.getElementById("site_nav_top");
            String navTop = element2.text();
            System.out.println("座右銘：" + navTop);
            
            /**
             * 3.根據樣式獲取元素
             */
            Elements elements3 = document.getElementsByClass("post_item");
            System.out.println("============根據樣式獲取元素=============");
            for(Element e : elements3){
                System.out.println(e.html());
                System.out.println("------------------------------");
            }
            
            /**
             * 4.根據屬性名稱來查詢DOM
             */
            Elements elements4 = document.getElementsByAttribute("width");
            System.out.println("============根據屬性名稱來查詢DOM=============");
            for(Element e : elements4){
                System.out.println(e.toString());
                System.out.println("------------------------------");
            }
            
            /**
             * 5.根據屬性名和屬性值來查詢DOM
             */
            Elements elements5 = document.getElementsByAttributeValue("target", "_blank");
            System.out.println("============ 根據屬性名和屬性值來查詢DOM=============");
            for(Element e : elements5){
                System.out.println(e.toString());
                System.out.println("------------------------------");
            }
        }
        if(response != null){
            response.close();
        }
        if(httpClient != null){
            httpClient.close();
        }
    }

Jsoup（二）-- Jsoup查找DOM元素