IO技術_File_API的使用規則
阿新 • • 發佈:2018-11-02
先連結一下檔案路徑的分隔符使用,一般用左斜線,Windows的右斜線需要轉義
/** * \/ 名稱分隔符 separator * @param args */ public static void main(String[] args) { String path = "F:\\workspace\\IO_study01\\13442345515565744.jpg"; System.out.println(File.separatorChar); //建議: //1:/ path = "F:/workspace/IO_study01/13442345515565744.jpg"; System.out.println(path); //2:常量拼接 path = "F:"+File.separator+"workspace"+File.separator+"IO_stydy01"+File.separator+"13442345515565744.jpg"; System.out.println(path); }
根據File 的構造器構建物件:jdk手冊:
/** * 構建File物件 * @param args */ public static void main(String[] args) { String path = "F:/workspace/IO_study01/13442345515565744.jpg"; //1,構建File物件 :路徑名 File src = new File(path); System.out.println(src.length()); //2,構建File物件: 父子路徑 src = new File("F:/workspace/IO_study01","13442345515565744.jpg"); src = new File("F:/workspace","IO_study01/13442345515565744.jpg"); System.out.println(src.length()); //3,構建File物件:父物件,子名稱 src = new File(new File("F:/workspace/IO_study01"),"13442345515565744.jpg"); System.out.println(src.length()); }
區分相對路徑和絕對路徑:
/** * 構建File物件 * 相對路徑和絕對路徑 * 1:存在碟符:絕對路徑 * 2:不存在碟符,相對路徑 * @param args */ public static void main(String[] args) { String path = "F:/workspace/IO_study01/13442345515565744.jpg"; //絕對路徑 File src = new File(path); System.out.println(src.getAbsolutePath());//獲取絕對路徑 //相對路徑 src = new File("13442345515565744.jpg"); System.out.println(src.getAbsolutePath());//獲取絕對路徑 //構建一個不存在的路徑 src = new File("aa/fdf.jpg"); System.out.println(src.getAbsolutePath()); }