Java IO流讀寫檔案的幾個注意點
阿新 • • 發佈:2019-02-08
平時寫IO相關程式碼機會挺少的,但卻都知道使用BufferedXXXX來讀寫效率高,沒想到裡面還有這麼多陷阱,這兩天突然被其中一個陷阱折騰一下:讀一個檔案,然後寫到另外一個檔案,前後兩個檔案居然不一樣?
解決這個問題之後,總結了幾個注意點。
注意點一:Reader/Writer讀寫二進位制檔案是有問題的 :
- public void copyFile1() {
- File srcFile = new File("E://atest//atest.txt");
- File dstFile = new File("E://btest//btest.txt");
- BufferedReader in = null;
- BufferedWriter out = null;
- try {
- in = new BufferedReader(new FileReader(srcFile));
- out = new BufferedWriter(new FileWriter(dstFile));
- String line = null;
- while((line = in.readLine()) != null) {
- out.write(line+"/r/n");
- }
- }catch (Exception e) {
- // TODO: handle exception
- e.printStackTrace();
- }finally {
- if(in != null) {
- try {
- in.close();
- }catch (Exception e) {
- // TODO: handle exception
- e.printStackTrace();
- }
- }
- if(out != null) {
- try {
- out.close();
- }catch (Exception e) {
- // TODO: handle exception
- e.printStackTrace();
- }
- }
- }
- public void copyFile() {
- File srcFile = new File("E://atest//atest.gif");
- File dstFile = new File("E://atest//btest.gif");
- BufferedInputStream in = null;
- BufferedOutputStream out = null;
- try {
- in = new BufferedInputStream(new FileInputStream(srcFile));
- out = new BufferedOutputStream(new FileOutputStream(dstFile));
- byte[] b = new byte[1024];
- while(in.read(b) != -1) {
- out.write(b);
- }
- }catch (Exception e) {
- // TODO: handle exception
- e.printStackTrace();
- }finally {
- if(in != null) {
- try {
- in.close();
- }catch (Exception e) {
- // TODO: handle exception
- e.printStackTrace();
- }
- }
- if(out != null) {
- try {
- out.close();
- }catch (Exception e) {
- // TODO: handle exception
- e.printStackTrace();
- }
- }
- }
- }