如何高效实现GBK与UTF-8编码互转及添加删除BOM，为Easy CHM合成前的文件转码改写？

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javapackage linwancheng.charset;

import java.io.File;import java.io.FileFilter;import java.io.FileInputStream;import java.io.FileOutputStream;import java.io.BufferedReader;import java.io.BufferedWriter;

CharsetUnits.java

package linwancheng.charset; import java.io.File; import java.io.FileFilter; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.BufferedReader; import java.io.BufferedWriter; import java.io.InputStreamReader; import java.io.OutputStreamWriter; import java.util.ArrayList; /** * 文件转码工具类，支持增删 UTF-8 的 BOM，添加HTML4标签兼容旧CHM阅读器 * * @param filter * 过滤器，可为空，或new NameEnd(拓展名...) * @param srcPath * @param descPath * @param inCharset * @param outCharset * @param addH4charset * 是否添加HTML4标签兼容旧CHM阅读器，true/flase * @param addBOM * +1 添加BOM，-1 删除，0 不变 * * @author linWanCheng * @version 2.0 */ public class CharsetUnits { final static String BOM = new String(new byte[] { -17, -69, -65 }); /** srcfile 转码到 descfile 不带BOM */ public static void src2desc(FileFilter filter, String inCharset, String outCharset) { src2desc(filter, "srcfile", "descfile", inCharset, outCharset, false, -1); } /** srcfile 转码到 descfile */ public static void src2desc(FileFilter filter, String inCharset, String outCharset, boolean addH4charset, int addBOM) { src2desc(filter, "srcfile", "descfile", inCharset, outCharset, addH4charset, addBOM); } /** 文件夹转码 */ public static void src2desc(FileFilter filter, String srcPath, String descPath, String inCharset, String outCharset, boolean addH4charset, int addBOM) { ArrayList fileList = new ArrayList (); listDeep(fileList, filter, false, true, new File(srcPath)); for (int i = 0; i < fileList.size(); i++) { String inPath = fileList.get(i).getPath(); System.out.println((i + 1) + "/" + fileList.size());// 显示进度 String outPath = descPath + inPath.substring(inPath.indexOf("\\")); new File(outPath.substring(0, outPath.lastIndexOf("\\"))).mkdirs(); ToUTF8(inPath, outPath, inCharset, outCharset, addH4charset, addBOM); } } /** 单个文件转码 */ public static void ToUTF8(String inPath, String outPath, String inCharset, String outCharset, boolean addH4charset, int addBOM) { try { BufferedReader in = new BufferedReader(new InputStreamReader(new FileInputStream(inPath), inCharset)); BufferedWriter out = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(outPath, addBOM > 0), outCharset)); String readLine; if ((readLine = in.readLine()) != null) { if (addBOM != 0) { boolean hasBOM = BOM.equals(readLine.substring(0, 2)); if (!hasBOM && addBOM > 0) { readLine = BOM + readLine; } if (hasBOM && addBOM < 0) { readLine = readLine.substring(2); } } out.write(readLine); out.newLine(); } while ((readLine = in.readLine()) != null) { out.write(readLine); out.newLine(); // 添加HTML4标签兼容旧CHM阅读器 if (addH4charset && readLine.startsWith(" "); out.newLine(); } } in.close(); out.close(); } catch (Exception e) { throw new RuntimeException(e); } } /** * 判断是否已有BOM * * @param path * @return */ public static boolean hasBOM(String path) { boolean result; try { FileInputStream in = new FileInputStream(path); byte[] b = new byte[3]; in.read(b); in.close(); result = (b[0] == -17 && b[1] == -69 && b[2] == -65); } catch (Exception e) { throw new RuntimeException(e); } return result; } /** * 递归子文件夹类的文件夹或文件存入集合 * * @param fileList * 要存入的集合 */ public static void listDeep(ArrayList fileList, FileFilter filter, boolean dir, boolean file, File... files) { for (File f : files) { if (f.isDirectory()) { if (dir) fileList.add(f); listDeep(fileList, filter, dir, file, f.listFiles(filter)); } else if (file) fileList.add(f); } } } /** * 过滤器，忽略大小写 * * @author linWanCheng */ class NameEnd implements FileFilter { String[] nameEnds; public NameEnd(final String... nameEnds) { this.nameEnds = nameEnds; } @Override public boolean accept(final File pathname) { if (pathname.isDirectory()) return true; String name = pathname.getName(); int index = name.lastIndexOf(".") + 1; String en = index == 0 ? "" : name.substring(index); for (String e : nameEnds) { if (en.equalsIgnoreCase(e)) return true; } return false; } } CharsetTest.java

package linwancheng.charset; import org.junit.Test; /** * 转码工具测试类 * 需要Junit 单元测试工具包 * MyEclipse 下点击方法名运行 */ public class CharsetTest { /** * MyEclipse文件转到到IDEA用 */ @Test public void DelBOM() { CharsetUnits.src2desc(null, "UTF-8", "UTF-8", false, -1); } @Test public void GBKToUTF8() { CharsetUnits.src2desc(null, "GBK", "UTF-8", false, -1); } /** * EasyCHM合成前添加BOM */ @Test public void ForEasyCHM() { CharsetUnits.src2desc(new NameEnd("htm", "html"), "GBK", "UTF-8", true, +1); } @Test public void UTF8ToGBK() { CharsetUnits.src2desc(null, "UTF-8", "GBK", false, -1); } }