java常用的

本文介绍了一系列实用的Java文件操作技巧,包括文本转码、创建MP3文件、获取WEB-INF目录路径、文件大小转换等方法,并提供了去除字符串数组中重复元素及类型转换的功能。
/**
   * 将文本转码 
   * @param args
   * @throws Exception
   */
    public static String encodeString(String text){
               try {
                         return URLEncoder. encode(text,"utf-8");
            } catch (UnsupportedEncodingException e) {
                         // TODO Auto-generated catch block
                        e.printStackTrace();
            }
                         return null;
   }

/**
    * 产生MP3文件
    * @param is
    * @param fileName
    */
   public static String createNewFile(InputStream is,String fileName) {
            FileOutputStream fos = null
             // 将输入流is写入文件输出流 fos
             int ch = 0;
             try 
                         // 打开一个已存在文件的输出流
                        fos = new FileOutputStream(fileName);
                         while((ch=is.read()) != -1){
                                    fos.write(ch);
                        }
                         return fileName;
            } catch (Exception e) {
                        e.printStackTrace();
            } finally{
                                     try {
                                                fos.close();
                                                is.close();
                                    } catch (IOException e) {
                                                 // TODO Auto-generated catch block
                                                e.printStackTrace();
                                    }
            }
             return null;
 }



/**
 *java普通类获取WEB-INF/的路径
 *
 */
package common;

import java.io.File;

public class FileUtis {
            
             public String getPath(){
                         String pathStr = this.getClass().getClassLoader().getResource( "").getPath();
                          // 对 Windows 下获取 物理路径 做 特殊处理
                          if( "\\".equals(File. separator)) {
                             pathStr = pathStr.substring(1).replaceAll( "/", "\\\\");
                         }
                          String path=pathStr.split("WEB-INF")[0]+ "upload"+File. separatorChar;
                          File file= new File(path);
                          if(!file.exists()){ //当文件路径不存在
                                      file.mkdir();
                          }
                          return path;
            }
           //删除文件 
           public void removeFile(String filePath){
                        File file= new File(filePath);
                         if(file.exists()){ //判断文件是否存在
                                    file.delete();
                        } else{
                                    System. out.println( "文件不存在#删除文件 " +filePath+" 失败" );
                        }
            }
            
             public static void main(String[] args) {
                        FileUtis fu= new FileUtis();
                        System. out.println(fu.getPath());
                        fu.removeFile( "D:\\zhangliangFile\\work8.6\\car_timer\\WebRoot\\upload\\sss.txt" );
            }
}




     //文件大小转换
    public static String convertFileSize( long size) {
        long kb = 1024;
        long mb = kb * 1024;
        long gb = mb * 1024;
 
        if (size >= gb) {
            return String. format("%.1f GB", ( float) size / gb);
        } else if (size >= mb) {
            float f = ( float) size / mb;
            return String. format(f > 100 ? "%.0f MB" : "%.1f MB", f);
        } else if (size >= kb) {
            float f = ( float) size / kb;
            return String. format(f > 100 ? "%.0f KB" : "%.1f KB", f);
        } else
            return String. format("%d B", size);
    }

 

/**
    * 去除String[]中的重复元素
    *
@param temp
    *
@return
    */
             public static List<String> removeCopyAttr(String[] temp){
                         List<String> obj= new ArrayList<String>();
                        
                         List<String> list = new LinkedList<String>();
                        
                    for( int i = 0; i < temp. length; i++) {
                        if(!list.contains(temp[i])) {
                            list.add(temp[i]);
                        }
                    }
                   
                    String[] rowsTemp = list.toArray( new String[list.size()]);
                   
                    if(rowsTemp!= null && rowsTemp. length > 0) {
                        for( int i=0; i<rowsTemp. length; i++) {
                                    obj.add(rowsTemp[i]);
                        }
                    }
                   
                    return obj;
             }


            /**
             * 把String数组转换成Integer数组
             * @param strArray
             * @return
             */
             public static Integer[] convertStrArrayToInt(String[]strArray){
                         if(strArray!= null&&strArray. length>0){
                                    Integer array[]= new Integer[strArray. length];
                                     for( int i=0;i<strArray. length;i++){ 
                                        array[i]=Integer. parseInt(strArray[i]);
                                    }
                                     return array;
                        } else{
                                     return null;
                        }
            }


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