使用Java?，如何把指定長度的字節寫入文件呢，或者說如何從inputStream 中讀取指定長度的字節寫入outputStream中呢？

Java代碼??

/***?

?????*?write?inputstream?into?file?according?to?specified?length.?

?????*??

?????*?@param?file?

?????*?@param?ins?

?????*????????????:?not?closed?

?????*?@param?length2?

?????*?@throws?IOException?

?????*/??

????public?static?FileOutputStream?writeInputStream2File(File?file,??

????????????InputStream?ins,?long?length2,?boolean?isCloseOutputStream)??

????????????throws?IOException?{??

????????String?parentDir?=?SystemHWUtil.getParentDir(file.getAbsolutePath());??

????????File?fatherFile?=?new?File(parentDir);??

????????if?(!fatherFile.exists())?{??

????????????fatherFile.mkdirs();??

????????}??

????????FileOutputStream?outs?=?new?FileOutputStream(file);??

????????int?readSize;??

????????byte[]?bytes?=?null;??

????????bytes?=?new?byte[(int)?length2];??

??

????????long?length_tmp?=?length2;??

????????while?((readSize?=?ins.read(bytes))?!=?SystemHWUtil.NEGATIVE_ONE/*-1*/)?{??

????????????length_tmp?-=?readSize;??

??

????????????outs.write(bytes,?0,?readSize);??

????????????if?(length_tmp?==?0)?{??

????????????????break;??

????????????}??

????????????//非常重要，千萬不能去掉!!!??

?????????????if?(length_tmp?<?SystemHWUtil.BUFF_SIZE/*4096*/)?{??

?????????????bytes?=?new?byte[(int)?length_tmp];??

?????????????}??

????????}??

????????outs.flush();??

????????if?(isCloseOutputStream)?{??

????????????outs.close();??

????????}??

????????return?outs;??

????}??

??

/***?

?????*?Not?responsible?for?closing?the?output?and?input?stream?寫入指定長度的字節到輸出流?

?????*??

?????*?@param?fin?

?????*?@param?fout?

?????*????????????:?The?divided?file?

?????*?@param?length2?

?????*?@throws?IOException?

?????*/??

????public?static?void?writeFromFile2File(InputStream?fin,?OutputStream?fout,??

????????????long?length2)?throws?IOException?{??

??????????

????????if?(length2?==?0)?{//?want?to?write?zero?bytes??

????????????//?if?(fout?!=?null)?{??

????????????//?fout.close();??

????????????//?}??

????????????return;??

????????}??

????????int?readSize;??

????????byte[]?bytes?=?null;??

????????if?(length2?>=?SystemHWUtil.BUFF_SIZE)?{??

????????????bytes?=?new?byte[SystemHWUtil.BUFF_SIZE];??

????????}?else?{??

????????????bytes?=?new?byte[(int)?length2];??

????????}??

??

????????long?length_tmp?=?length2;??

????????while?((readSize?=?fin.read(bytes))?!=?SystemHWUtil.NEGATIVE_ONE)?{??

??????????????

????????????length_tmp?-=?readSize;??

????????????fout.write(bytes,?0,?readSize);??

????????????if?(length_tmp?==?0)?{??

????????????????break;??

????????????}??

????????????//非常重要，千萬不能刪除??

?????????????if?(length_tmp?<?SystemHWUtil.BUFF_SIZE)?{??

?????????????bytes?=?new?byte[(int)?length_tmp];??

?????????????}??

????????}??

??

????}??

??

????/***?

?????*?Responsible?for?closing?the?output?stream?

?????*??

?????*?@param?fin?

?????*?@param?outPutFile?

?????*?@param?length2?

?????*????????????:The?number?of?bytes?to?be?written?

?????*?@param?append?

?????*????????????:?Whether?additional?

?????*?@throws?IOException?

?????*/??

????public?static?void?writeFromFile2File(FileInputStream?fin,?File?outPutFile,??

????????????long?length2,?boolean?append)?throws?IOException?{??

??????????

????????if?(length2?==?0)?{//?want?to?write?zero?bytes??

????????????return;??

????????}??

????????FileOutputStream?fout?=?null;??

????????try?{??

????????????fout?=?new?FileOutputStream(outPutFile,?append/*?追加?*/);??

????????}?catch?(FileNotFoundException?e1)?{??

????????????e1.printStackTrace();??

????????}??

????????try?{??

????????????writeFromFile2File(fin,?fout,?length2);??

????????}?catch?(IOException?e)?{??

????????????e.printStackTrace();??

????????}?finally?{??

????????????fout.flush();??

????????????fout.close();//?Close?the?stream??

????????}??

????}??

?上述代碼見附件中io0007-find_progess\src\main\java\com\io\hw\file\util\FileUtils.java

依賴的包：is_chinese-0.0.2-SNAPSHOT.jar

參考：http://hw1287789687.iteye.com/blog/2023095

寫入文件:

Java代碼??

/***?

?????*?寫入文件?

?????*?@param?content?

?????*?@param?charset?

?????*?@param?readAndWriteResult?

?????*?@param?file?

?????*?@throws?IOException?

?????*/??

????private?static?void?writeStubFile(String?content,?String?charset,??File?file)?throws?IOException?{??

????????FileWriterWithEncoding?fileW?=?new?FileWriterWithEncoding(file,?charset);??

????????fileW.write(content);??

????????fileW.close();??

??????????

????} ?

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