能讓程序作的事情堅定不用人來作——批量修復markdownlint MD034警告

歡迎和你們交流技術相關問題：
郵箱: jiangxinnju@163.com
博客園地址: http://www.cnblogs.com/jiangxinnju
GitHub地址: https://github.com/jiangxincode
知乎地址: https://www.zhihu.com/people/jiangxinnju

如今各類編程語言都有本身的lint工具來作靜態檢查，防止一些低級錯誤並維持統一的風格。Markdown這樣的樣式標記語言也不例外，如今你們用的比較多的是markdownlint。該項目開源在github:https://github.com/markdownlint/markdownlint，當前不少實用markdown語言的項目都使用該工具。

markdownlint的檢查規則目前有41項https://github.com/markdownlint/markdownlint/blob/master/docs/RULES.md，其中"MD034 - Bare URL used"是你們常常遇到的問題，若是你在Markdown文檔中使用URL，可是沒有在URL周圍使用<>的話就會產生警告，我維護了一個相似於awesome的項目https://github.com/jiangxincode/cnblogs，其中報了1000多個相似的警告，若是所有手工來修改估計手都回廢掉，所以寫了個小程序在全部的.md文檔中的全部url兩遍加上了<>。

程序使用Java編寫，比較簡單，主要使用了正則表達式的替換，程序以下：

package edu.jiangxin.tools;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * Solve the problem of MD034. <p>
 * {@link https://github.com/markdownlint/markdownlint/blob/master/docs/RULES.md}
 * This program doesn't process any exception!
 * @author aloys
 *
 */
public class MD034Solver {
    public static final String regex = "\\b(https?|ftp|file)://[-A-Z0-9+&@#/%?=~_|$!:,.;]*[A-Z0-9+&@#/%=~_|$]";
    
    public static final String sourceDirStr = "D:\\temp\\cnblogs";
    
    public static final String targetDirStr = "D:\\temp\\cnblogsbak";

    public static void main(String[] args) throws IOException {
        // Source directory must be a valid directory which contains the text files to be processed.
        File sourceDir = new File(sourceDirStr);

        // Target directory must be a valid directory which will save the proecessed files.
        File targetDir = new File(targetDirStr);

        for (File file : sourceDir.listFiles()) {

            // take off the .git directory and .gitignore file
            if (file.getName().startsWith(".")) {
                continue;
            }

            BufferedReader reader = new BufferedReader(new FileReader(file));
            BufferedWriter writer = new BufferedWriter(new FileWriter(new File(targetDir, file.getName())));

            String temp = null;
            while ((temp = reader.readLine()) != null) {
                Pattern pattern = Pattern.compile(regex, Pattern.CASE_INSENSITIVE | Pattern.UNICODE_CASE);
                Matcher regexMatcher = pattern.matcher(temp);
                StringBuffer sb = new StringBuffer();
                while (regexMatcher.find()) {
                    String group = regexMatcher.group();
                    int start = regexMatcher.start();
                    if (start >= 1 && (temp.charAt(start - 1) == '<' || temp.charAt(start - 1) == '(')) {
                        regexMatcher.appendReplacement(sb, group);
                    } else {
                        regexMatcher.appendReplacement(sb, "<" + group + ">");
                    }

                }
                regexMatcher.appendTail(sb);
                writer.write(sb.toString());
                writer.newLine();
            }
            reader.close();
            writer.close();
        }
    }

}