<tr>
<td>5345454354</td><td>2010-3-29 13:48:33</td><td>周杰伦</td>
</tr>
<tr>
<td>6565465466</td><td>2010-3-29 15:34:38</td><td>张学友</td>
</tr>
<tr>
<td>6546546546</td><td>2010-3-30 19:30:50</td><td>刘德华</td>
</tr>
<tr>
<td>9875646545</td><td>2010-3-31 2:20:58</td><td>郭富城</td>
</tr>
<tr>
<td>7868768768</td><td>2010-3-31 8:03:11</td><td>梁朝伟</td>
</tr>

若想取标记<td></td>之间的内容, 可以这样分析

<td>(.*?)</td>
string str = "..........";
string pstr = "<td>(.*?)</td>";
MatchCollection mc = Regex.Matches(str, pstr);
for (int i = 0; i < mc.Count; i++)
{ 
    Response.Write(mc[i].Result("$1"));
}
MatchCollection mc = Regex.Matches(html,@"(?is)(?<=<td>).+?(?=</td>)");
foreach(Match m in mc)
{ 
    //Response.Write(m.Value);//web
    MessageBox.Show(m.Value);
}

表达式说明

(?<=Expression) 逆序肯定环视，表示所在位置左侧能够匹配Expression
(?<!Expression) 逆序否定环视，表示所在位置左侧不能匹配Expression
(?=Expression) 顺序肯定环视，表示所在位置右侧能够匹配Expression
(?!Expression) 顺序否定环视，表示所在位置右侧不能匹配Expression

(?is)(?<=).+?(?=)
(?is) 模式修饰，i表示忽略大小写，s表示单行模式.能匹配回车换行
(?<=<td>) 逆序肯定环视,需要匹配的结果以<td>开头，但是<td>匹配，结果中不包含<td>
.+? 任意字符，每次匹配到符合的（任意字符），即尝试匹配后面的表达式，直到后面的表达式失败，回溯上一次匹配结果。
(?=</td>) 顺序肯定环视，匹配的结果最后要以</td>结尾，但</td>不匹配，结果中不包含</td>

正则取`xml`内容比`dom4j`快50倍？

long t1 = System.nanoTime();
String str = "<xml><ToUserName><![CDATA[gh_520f99dff7cc]]></ToUserName><FromUserName><![CDATA[oBAMOs3aZB0dkbILsBR1wksbmli4]]></FromUserName><CreateTime>1416900555</CreateTime><MsgType><![CDATA[event]]></MsgType><Event><![CDATA[MASSSENDJOBFINISH]]></Event><MsgID>2348714844</MsgID><Status><![CDATA[send success]]></Status><TotalCount>1</TotalCount><FilterCount>1</FilterCount><SentCount>1</SentCount><ErrorCount>0</ErrorCount></xml>";
// Document doc = null;
// try { 
// doc = DocumentHelper.parseText(str);
// } catch (DocumentException e) { 
// log.error("解析群发xml错误："+e.getMessage(), e);
// }
// 
// Element root = doc.getRootElement();
// String msgid = root.elementTextTrim("MsgID");
// String Status = root.elementTextTrim("Status");
// String TotalCount = root.elementTextTrim("TotalCount");
// String FilterCount = root.elementTextTrim("FilterCount");
// String SentCount = root.elementTextTrim("SentCount");
// String ErrorCount = root.elementTextTrim("ErrorCount");
            String msgid = RegExp.getString(str,
                    "(?<=<MsgID>)[\\s\\S]*?(?=</MsgID>)").trim();
            String Status = RegExp.getString(str,
                "(?<=<Status><!\\[CDATA\\[)[\\s\\S]*?(?=\\]\\]></Status>)")
                .trim();
            String TotalCount = RegExp.getString(str,
                "(?<=<TotalCount>)[\\s\\S]*?(?=</TotalCount>)")
                .trim();
            String FilterCount = RegExp.getString(str,
                "(?<=<FilterCount>)[\\s\\S]*?(?=</FilterCount>)")
                .trim();
            String SentCount = RegExp.getString(str,
                "(?<=<SentCount>)[\\s\\S]*?(?=</SentCount>)")
                .trim();
            String ErrorCount = RegExp.getString(str,
                "(?<=<ErrorCount>)[\\s\\S]*?(?=</ErrorCount>)")
                .trim();
            long t2 = System.nanoTime();
            log.info(t2-t1);
            log.info((t2-t1)*0.000001);
            log.info(msgid+", "+Status+", "+TotalCount+", "+FilterCount+", "+SentCount+", "+ErrorCount);

dom4j运行结果：

2014-11-26 15:25:29,716 INFO [Test] 70 - <220279310>
2014-11-26 15:25:29,719 INFO [Test] 71 - <220.27930999999998>《==看这里
2014-11-26 15:25:29,719 INFO [Test] 72 - <2348714844, send success, 1, 1, 1, 0>

正则运行结果：

2014-11-26 15:28:08,575 INFO [Test] 70 - <4633684>
2014-11-26 15:28:08,578 INFO [Test] 71 - <4.633684>《==看这里
2014-11-26 15:28:08,578 INFO [Test] 72 - <2348714844</MsgID>, <![CDATA[send success]]></Status>, 1</TotalCount>, 1</FilterCount>, 1</SentCount>, 0</ErrorCount>>

正则代码：

public class RegExp { 
    public static ArrayList<String> getStrs(String source, String regex) { 
        Pattern p = Pattern.compile(regex);
        Matcher m = p.matcher(source);
        ArrayList<String> list = new ArrayList();
        while (m.find()) { 
            list.add(source.substring(m.start(), m.end()));
        }
        return list;
    }
    public static String getString(String source, String regex) { 
        ArrayList<String> list = getStrs(source, regex);
        if (list.size() > 0) { 
            return (String) list.get(0);
        }
        return "";
    }
    public static ArrayList<String> getStrs(String source, String beginStr,
        String endStr, boolean isLong) { 
        if (isLong) { 
            return getStrs(source,
                "(?<=" + replay(beginStr) + ")[\\s\\S]*(?=" + replay(endStr) +
                ")");
        }
        return getStrs(source,
            "(?<=" + replay(beginStr) + ")[\\s\\S]*?(?=" + replay(endStr) +
            ")");
    }
    public static String getString(String source, String beginStr,
        String endStr, boolean isLong) { 
        if (isLong) { 
            return getString(source,
                "(?<=" + replay(beginStr) + ")[\\s\\S]*(?=" + replay(endStr) +
                ")");
        }
        return getString(source,
            "(?<=" + replay(beginStr) + ")[\\s\\S]*?(?=" + replay(endStr) +
            ")");
    }
    private static String replay(String source) { 
        String result = "";
        result = source.replace("\\", "\\\\");
        result = source.replace(".", "\\.");
        result = result.replace("(", "\\(");
        result = result.replace(")", "\\)");
        result = result.replace("[", "\\[");
        result = result.replace("]", "\\]");
        result = result.replace("{", "\\{");
        result = result.replace("}", "\\}");
        result = result.replace("$", "\\$");
        result = result.replace("?", "\\?");
        result = result.replace("&", "\\&");
        result = result.replace("*", "\\*");
        result = result.replace("!", "\\!");
        result = result.replace("^", "\\^");
        result = result.replace("+", "\\+");
        result = result.replace("#", "\\#");
        return result;
    }
}