import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.PushbackInputStream;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

public class UtfTool
{

    /**
     * ant 编译之后的result文件，注意要编译提示错误的文件名要在同一行
     * 可以设置命令提示窗口的缓冲区大小实现
     * @param resultFileName
     */
    public static Set getFileNamesFromCompileResult(String resultFileName)
     throws java.io.IOException
    {
 Set<String> set = new HashSet();
 BufferedReader reader = new BufferedReader(new FileReader(
  resultFileName));
 String start = "[javac] ";
 int startLen = start.length();
 String end = ".java:";
 int endLen = end.length();
 
 String errMsg = "\\65279";
 while (reader.ready())
 {
     String line = reader.readLine();
     int indexStart = line.indexOf(start);
    
     if(line.indexOf(errMsg) == -1)
     {
  continue;
     }
     if (indexStart != -1)
     {
  int indexEnd = line.indexOf(end);
  if (indexEnd != -1)
  {
      String name = line.substring(indexStart + startLen,
       indexEnd + endLen - 1);
      set.add(name.trim());
  }
     }
 }
 return set;

    }
   
    /**
     * 读取流中前面的字符，看是否有bom，如果有bom，将bom头先读掉丢弃
     * @param in
     * @return
     * @throws IOException
     */
    public static InputStream getInputStream(InputStream in) throws IOException
    {

 PushbackInputStream testin = new PushbackInputStream(in);
 int ch = testin.read();
 if (ch != 0xEF)
 {
     testin.unread(ch);
 } else if ((ch = testin.read()) != 0xBB)
 {
     testin.unread(ch);
     testin.unread(0xef);
 } else if ((ch = testin.read()) != 0xBF)
 {
     throw new IOException("错误的UTF-8格式文件");
 } else
 {
     //不需要做，这里是bom头被读完了
    //// System.out.println("still exist bom");

 }
 return testin;

    }
   
   
   
    /**
     * 根据一个文件名，读取完文件，干掉bom头。
     * @param fileName
     * @throws IOException
     */
    public static void trimBom(String fileName) throws IOException
    {

 FileInputStream fin = new FileInputStream(fileName);
 //开始写临时文件
 InputStream in = getInputStream(fin);
 String tmpFileName = fileName + ".tmp";
 FileOutputStream out = new FileOutputStream(tmpFileName);
 byte b[] = new byte[4096];

 int len = 0;
 while (in.available() > 0)
 {
     len = in.read(b, 0, 4096);
     out.write(b, 0, len);
 }

 in.close();
 fin.close();
 out.close();

 //临时文件写完，开始将临时文件写回本文件。
 in = new FileInputStream(tmpFileName);
 System.out.println("[" + fileName + "]");
 out = new FileOutputStream(fileName);

 while (in.available() > 0)
 {
     len = in.read(b, 0, 4096);
     out.write(b, 0, len);
 }
 in.close();
 out.close();
    }

    /**
     * 根据ant编译错误来去除bom
     * @param resultFile
     * @throws IOException
     */
    static void trimBomByCompileResult(String resultFile) throws IOException
    {
 Set<String> set = getFileNamesFromCompileResult(resultFile);
 for (String fName : set)
 {
     trimBom(fName);
 }
    }

    public static void main(String[] args) throws IOException
    {
 trimBomByCompileResult("c:/result3.txt");
 
 ///List<String> list = getFileNamesFromCompileResult(resultFile);

// InputStream in = new FileInputStream(
//  "D:/cc/SSB_SRC_DEV_lijinglin2/TP_SSB/SSB_CJ203_Component/ProductCode/com/zte/ssb/component/access/implementation/dao/ImplementationDAO.java");
// getInputStream2(in);
// in.close();
    }
}