jsoup 就是用来处理 html dom的一个组件。其与dom4j、xstream等xml dom组件类似。
jsoup加载完html文本生成document对象之后，用来操作dom的通用操作就可以使用了。如：getElementById、getElementsByName等。
代码：加载html文本为dom对象，获取id为username的元素的属性value的值
Document doc = Jsoup.parse(htmlString);
String username = doc.getElementById("username").attr("value");
另附上 httpclient jar包 jsoup jar包
httpclient设置头部参数，以及获取头部参数，设置消息体参数的代码：
httpclient设置头部参数
/**
* 设置请求头
* @param post
*/
private static void setHeaders(HttpPost post) {
post.setHeader("Accept", "text/html, application/xhtml+xml, */*");
post.setHeader("Accept-Language", "zh-CN");
post.setHeader("User-Agent", "Mozilla/5.0 (Windows NT 6.1; WOW64; Trident/7.0; rv:11.0) like Gecko");
post.setHeader("Content-Type", "application/x-www-form-urlencoded");
post.setHeader("Accept-Encoding", "gzip, deflate");
post.setHeader("DNT", "1");
post.setHeader("Connection", "Keep-Alive");
post.setHeader("Cache-Control", "no-cache");
post.setHeader("Cookie", Cookie);
}
/**
* 设置请求头
* @param get
*/
private static void setHeaders(HttpGet get) {
get.setHeader("Accept", "text/html, application/xhtml+xml, */*");
get.setHeader("Accept-Language", "zh-CN");
get.setHeader("User-Agent", "Mozilla/5.0 (Windows NT 6.1; WOW64; Trident/7.0; rv:11.0) like Gecko");
get.setHeader("Content-Type", "application/x-www-form-urlencoded");
get.setHeader("Accept-Encoding", "gzip, deflate");
get.setHeader("DNT", "1");
get.setHeader("Connection", "Keep-Alive");
get.setHeader("Cache-Control", "no-cache");
get.setHeader("Cookie", Cookie);
}
httpclient发送get请求
private static String getSessionId() throws IOException, Exception {
HttpClient client = new DefaultHttpClient();
HttpGet get = new HttpGet("http://url/");
HttpResponse responsex = client.execute(get);
Header[] headers = responsex.getAllHeaders();
for (int i = 0; i < headers.length; i++) {
Header header = headers[i];
String name = header.getName();
String value = header.getValue();
if("Set-Cookie".equals(name)){
String[] vals = value.split(";");
for (int j = 0; j < vals.length; j++) {
String val = vals[j];
if(val.contains("ASP.NET_SessionId")){
Cookie = val;
}
}
}
}
if(!responsex.getStatusLine().toString().contains("HTTP/1.1 200 OK")){
throw new RuntimeException("某某失败");
}
HttpEntity entityx = responsex.getEntity();
String entityMsgx = EntityUtils.toString(entityx);
//解析html dom 得到输入参数
Document doc = Jsoup.parse(entityMsgx);
resetAllParams();
__VIEWSTATE = doc.getElementById("__VIEWSTATE").attr("value");
__EVENTVALIDATION = doc.getElementById("__EVENTVALIDATION").attr("value");
isOpen = doc.getElementById("isOpen").attr("value");
btlogin = doc.getElementById("btlogin").attr("value");
return Cookie;
}
发送post请求
/**
* 登录
* @param username
* @param password
* @throws IOException
* @throws Exception
*/
public static boolean login(String username, String password) throws IOException, Exception {
//先访问首页获取sessionid
getSessionId();
//执行登陆过程
HttpClient client = new DefaultHttpClient();
HttpPost post = new HttpPost("http://loginurl");
post.setHeader("Referer", "http://loginurl");
setHeaders(post);
// 登录表单的信息
List qparams = new ArrayList();
qparams.add(new BasicNameValuePair("__VIEWSTATE", __VIEWSTATE));
qparams.add(new BasicNameValuePair("__EVENTVALIDATION", __EVENTVALIDATION));
qparams.add(new BasicNameValuePair("isOpen", isOpen));
qparams.add(new BasicNameValuePair("Text1", username));
qparams.add(new BasicNameValuePair("Password1", password));
qparams.add(new BasicNameValuePair("btlogin", btlogin));
UrlEncodedFormEntity params = new UrlEncodedFormEntity(qparams, "utf-8");
post.setEntity(params);
// 相当于按了下确定登录的按钮，也就是浏览器调转了
HttpResponse response = client.execute(post);
if(!response.getStatusLine().toString().contains("HTTP/1.1 200 OK")){
throw new RuntimeException("离校系统登陆失败");
}
HttpEntity entity = response.getEntity();
String entityMsg = EntityUtils.toString(entity);
if(entityMsg.contains("该用户不存在或用户名密码错误")){
throw new RuntimeException("该用户不存在或用户名密码错误");
}
return true;
}