正则表达式处理XML,HTML

分手后的思念是犯贱 2021-06-26 16:06 287阅读 0赞

若想取标记`<td></td>`之间的内容, 可以这样分析

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)(?<=<td>).+?(?=</td>)

*  `(?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;
        }
    }