Java字符集编码与转码

package lavasoft.common; 

import org.apache.commons.logging.Log; 
import org.apache.commons.logging.LogFactory; 

import java.io.*; 

/** 
* 转码工具，全面支持文件、字符串的转码 
* 
* @author Administrator 2009-11-29 16:14:21 
*/ 
public  class EncodingToolkit { 
         private  static Log log = LogFactory.getLog(EncodingToolkit. class); 

         public  static  void main(String[] args) { 
                String han =  "汉"; 


                System.out.println( "---------"); 
        } 

         /** 
         * 对字符串重新编码 
         * 
         * @param text                字符串 
         * @param resEncoding 源编码 
         * @param newEncoding 新编码 
         * @return 重新编码后的字符串 
         */ 
         public  static String reEncoding(String text, String resEncoding, String newEncoding) { 
                String rs =  null; 
                 try { 
                        rs =  new String(text.getBytes(resEncoding), newEncoding); 
                }  catch (UnsupportedEncodingException e) { 
                        log.error( "读取文件为一个内存字符串失败，失败原因是使用了不支持的字符编码"); 
                         throw  new RuntimeException(e); 
                } 
                 return rs; 
        } 

         /** 
         * 重新编码Unicode字符串 
         * 
         * @param text                源字符串 
         * @param newEncoding 新的编码 
         * @return 指定编码的字符串 
         */ 
         public  static String reEncoding(String text, String newEncoding) { 
                String rs =  null; 
                 try { 
                        rs =  new String(text.getBytes(), newEncoding); 
                }  catch (UnsupportedEncodingException e) { 
                        log.error( "读取文件为一个内存字符串失败，失败原因是使用了不支持的字符编码" + newEncoding); 
                         throw  new RuntimeException(e); 
                } 
                 return rs; 
        } 

         /** 
         * 文本文件重新编码 
         * 
         * @param resFile         源文件 
         * @param resEncoding 源文件编码 
         * @param distFile        目标文件 
         * @param newEncoding 目标文件编码 
         * @return 转码成功时候返回ture，否则false 
         */ 
         public  static  boolean reEncoding(File resFile, String resEncoding, File distFile, String newEncoding) { 
                 boolean flag =  true; 
                InputStreamReader reader =  null; 
                OutputStreamWriter writer =  null; 
                 try { 
                        reader =  new InputStreamReader( new FileInputStream(resFile), resEncoding); 
                        writer =  new OutputStreamWriter( new FileOutputStream(distFile), newEncoding); 
                         char buf[] =  new  char[1024 * 64];          //字符缓冲区 
                         int len; 
                         while ((len = reader.read(buf)) != -1) { 
                                writer.write(buf, 0, len); 
                        } 
                        writer.flush(); 
                        writer.close(); 
                        reader.close(); 
                }  catch (FileNotFoundException e) { 
                        flag =  false; 
                        log.error( "没有找到文件，转码发生异常！"); 
                         throw  new RuntimeException(e); 
                }  catch (IOException e) { 
                        flag =  false; 
                        log.error( "读取文件为一个内存字符串失败，失败原因是读取文件异常！"); 
                         throw  new RuntimeException(e); 
                }  finally { 
                         if (reader !=  null)  try { 
                                reader.close(); 
                        }  catch (IOException e) { 
                                flag =  false; 
                                 throw  new RuntimeException(e); 
                        }  finally { 
                                 if (writer !=  null)  try { 
                                        writer.close(); 
                                }  catch (IOException e) { 
                                        flag =  false; 
                                         throw  new RuntimeException(e); 
                                } 
                        } 
                } 
                 return flag; 
        } 

         /** 
         * 读取文件为一个Unicode编码的内存字符串,保持文件原有的换行格式 
         * 
         * @param resFile    源文件对象 
         * @param encoding 文件字符集编码 
         * @return 文件内容的Unicode字符串 
         */ 
         public  static String file2String(File resFile, String encoding) { 
                StringBuffer sb =  new StringBuffer(); 
                 try { 
                        LineNumberReader reader =  new LineNumberReader( new BufferedReader( new InputStreamReader( new FileInputStream(resFile), encoding))); 
                        String line; 
                         while ((line = reader.readLine()) !=  null) { 
                                sb.append(line).append(System.getProperty( "line.separator")); 
                        } 
                        reader.close(); 
                }  catch (UnsupportedEncodingException e) { 
                        log.error( "读取文件为一个内存字符串失败，失败原因是使用了不支持的字符编码" + encoding); 
                         throw  new RuntimeException(e); 
                }  catch (FileNotFoundException e) { 
                        log.error( "读取文件为一个内存字符串失败，失败原因所给的文件" + resFile +  "不存在！"); 
                         throw  new RuntimeException(e); 
                }  catch (IOException e) { 
                        log.error( "读取文件为一个内存字符串失败，失败原因是读取文件异常！"); 
                         throw  new RuntimeException(e); 
                } 
                 return sb.toString(); 
        } 

         /** 
         * 使用指定编码读取输入流为一个内存Unicode字符串,保持文件原有的换行格式 
         * 
         * @param in             输入流 
         * @param encoding 构建字符流时候使用的字符编码 
         * @return Unicode字符串 
         */ 
         public  static String stream2String(InputStream in, String encoding) { 
                StringBuffer sb =  new StringBuffer(); 
                LineNumberReader reader =  null; 
                 try { 
                        reader =  new LineNumberReader( new BufferedReader( new InputStreamReader(in, encoding))); 
                        String line; 
                         while ((line = reader.readLine()) !=  null) { 
                                sb.append(line).append(System.getProperty( "line.separator")); 
                        } 
                        reader.close(); 
                        in.close(); 
                }  catch (UnsupportedEncodingException e) { 
                        log.error( "读取文件为一个内存字符串失败，失败原因是使用了不支持的字符编码" + encoding); 
                         throw  new RuntimeException(e); 
                }  catch (IOException e) { 
                        log.error( "读取文件为一个内存字符串失败，失败原因是读取文件异常！"); 
                         throw  new RuntimeException(e); 
                }  finally { 
                         if (in !=  null)  try { 
                                in.close(); 
                        }  catch (IOException e) { 
                                log.error( "关闭输入流发生异常！", e); 
                                 throw  new RuntimeException(e); 
                        } 
                } 
                 return sb.toString(); 
        } 

         /** 
         * 字符串保存为制定编码的文本文件 
         * 
         * @param text         字符串 
         * @param distFile 目标文件 
         * @param encoding 目标文件的编码 
         * @return 转换成功时候返回ture，否则false 
         */ 
         public  static  boolean string2TextFile(String text, File distFile, String encoding) { 
                 boolean flag =  true; 
                 if (!distFile.getParentFile().exists()) distFile.getParentFile().mkdirs(); 
                OutputStreamWriter writer =  null; 
                 try { 
                        writer =  new OutputStreamWriter( new FileOutputStream(distFile), encoding); 
                        writer.write(text); 
                        writer.close(); 
                }  catch (IOException e) { 
                        flag =  false; 
                        log.error( "将字符串写入文件发生异常！"); 
                         throw  new RuntimeException(e); 
                }  finally { 
                         if (writer !=  null)  try { 
                                writer.close(); 
                        }  catch (IOException e) { 
                                log.error( "关闭输出流发生异常！", e); 
                                 throw  new RuntimeException(e); 
                        } 
                } 
                 return flag; 
        } 
}