java:如何将文件转换为utf8

Question

我有一个文件有一些非utf8 caracters(如"ISO-8859-1"),所以我想将该文件(或读取)转换为UTF8编码,我该怎么做？

它是这样的代码:

File file = new File("some_file_with_non_utf8_characters.txt");

/* some code to convert the file to an utf8 file */

...

编辑:放一个编码示例

Answer 1

以下代码将文件从srcEncoding转换为tgtEncoding:

public static void transform(File source, String srcEncoding, File target, String tgtEncoding) throws IOException {
    BufferedReader br = null;
    BufferedWriter bw = null;
    try{
        br = new BufferedReader(new InputStreamReader(new FileInputStream(source),srcEncoding));
        bw = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(target), tgtEncoding));
        char[] buffer = new char[16384];
        int read;
        while ((read = br.read(buffer)) != -1)
            bw.write(buffer, 0, read);
    } finally {
        try {
            if (br != null)
                br.close();
        } finally {
            if (bw != null)
                bw.close();
        }
    }
}

- 编辑 -

使用Try-with-resources(Java 7):

public static void transform(File source, String srcEncoding, File target, String tgtEncoding) throws IOException {
    try (
      BufferedReader br = new BufferedReader(new InputStreamReader(new FileInputStream(source), srcEncoding));
      BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(target), tgtEncoding)); ) {
          char[] buffer = new char[16384];
          int read;
          while ((read = br.read(buffer)) != -1)
              bw.write(buffer, 0, read);
    } 
}

Answer 2

  String charset = "ISO-8859-1"; // or what corresponds
  BufferedReader in = new BufferedReader( 
      new InputStreamReader (new FileInputStream(file), charset));
  String line;
  while( (line = in.readLine()) != null) { 
    ....
  }

你有文字解码.您可以通过simmetric Writer/OutputStream方法使用您喜欢的编码(例如UTF-8)来编写它.

Answer 3

您需要知道输入文件的编码.例如,如果文件是Latin-1,你会做这样的事情,

        FileInputStream fis = new FileInputStream("test.in");
        InputStreamReader isr = new InputStreamReader(fis, "ISO-8859-1");
        Reader in = new BufferedReader(isr);
        FileOutputStream fos = new FileOutputStream("test.out");
        OutputStreamWriter osw = new OutputStreamWriter(fos, "UTF-8");
        Writer out = new BufferedWriter(osw);

        int ch;
        while ((ch = in.read()) > -1) {
            out.write(ch);
        }

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