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java 读取文件在控制台打印将内容写入到文件

时间：2022-11-01 04:17:36

读取txt文本文件内容在控制台打印（5种方式）

字节流方式：

FileInputStream 字节输入流

/*** 字节输入流* 读取 txt 文件的内容并在控制台打印*/public static void tFileInputStream() throws Exception{FileInputStream fileInputStream = new FileInputStream("src/a.txt");byte[] bytes = new byte[1024*5];int len = 0;StringBuilder sb = new StringBuilder();while ((len = fileInputStream.read(bytes))!=-1){sb.append(new String(bytes,0,len));}fileInputStream.close();System.out.println(sb.toString());}

BufferedInputStream 字节输入缓冲流

/*** 字节输入缓冲流* 读取 txt 文件的内容并在控制台打印*/public static void tBufferedInputStream() throws Exception{BufferedInputStream inputStream = new BufferedInputStream(new FileInputStream("src/a.txt"));byte[] bytes = new byte[1024*5];int len = 0;StringBuilder sb = new StringBuilder();while ((len = inputStream.read(bytes))!=-1){sb.append(new String(bytes,0,len));}inputStream.close();System.out.println(sb);}

字符流方式：

InputStreamReader 字符输入流

/*** 字符输入流* 读取txt文件内容并在控制台打印*/public static void tInputStreamRead() throws Exception{InputStreamReader streamReader = new InputStreamReader(new FileInputStream("src/b.txt"));char[] chars = new char[10];int len = 0;StringBuilder sb = new StringBuilder();while ((len = streamReader.read(chars))!=-1){sb.append(chars,0,len);}streamReader.close();System.out.println(sb.toString());}

FileReader 便捷字符输入流

/*** 便捷字符输入流* 读取txt文件内容并在控制台打印*/public static void tFilRead() throws Exception {FileReader fileReader = new FileReader("src/a.txt");char[] chars = new char[1024];int len = 0;StringBuilder sb = new StringBuilder();while ((len = fileReader.read(chars))!=-1){sb.append(chars,0,len);}System.out.println(sb.toString());}

BufferedReader 字符缓冲输入流

/*** 字符缓冲输入流* 读取txt文件内容并在控制台打印*/public static void tBufferedRead() throws Exception{BufferedReader bufferedReader = new BufferedReader(new FileReader("src/a.txt"));char[] chars = new char[1024];int len = 0;StringBuilder sb = new StringBuilder();while ((len = bufferedReader.read(chars))!=-1){sb.append(chars,0,len);}bufferedReader.close();System.out.println(sb.toString());}

向txt文件内写入内容（5种方式）

字节流方式：

FileOutputStream 字节输出流

/*** 字节输出流* 将字符串写入到文件内*/public static void tFileOutPutStream() throws Exception{FileOutputStream outputStream = new FileOutputStream("src/b.txt");String str = "豫章故郡，洪都新府。星分翼轸，地接衡庐。襟三江而带五湖，控蛮荆而引瓯越";outputStream.write(str.getBytes());outputStream.close();System.out.println("内容写入成功！");}

BufferedOutputStream 字节输出缓冲流

/*** 字节输出缓冲流* 将字符串写入到文件内*/public static void tBuffrtedOutPutStream() throws Exception{BufferedOutputStream outputStream = new BufferedOutputStream(new FileOutputStream("src/b.txt"));String str = "龙光射牛斗之墟；人杰地灵，徐孺下陈蕃之榻。雄州雾列，俊采星驰。台隍枕夷夏之交，宾主尽东南之美。都督阎公之雅望，棨戟遥临；宇文新州之懿范，襜帷暂驻。十旬休假，胜友如云；千里逢迎，高朋满座。腾蛟起凤，孟学士之词宗；紫电青霜，王将军之武库。家君作宰，路出名区；童子何知，躬逢胜饯。\n" +"时维九月，序属三秋。潦水尽而寒潭清，烟光凝而暮山紫。";outputStream.write(str.getBytes());outputStream.close();System.out.println("内容写入成功！");}

字符流方式：

OutputStreamWriter 字符输出流

/*** 字符输出流* 将字符串写入到文件内*/public static void tBufferedWrite() throws Exception{OutputStreamWriter outputStreamWriter = new OutputStreamWriter(new FileOutputStream("src/b.txt"));String str = "潦水尽而寒潭清，烟光凝而暮山紫。俨骖騑于上路，访风景于崇阿；临帝子之长洲，得天人之旧馆。";outputStreamWriter.write(str);/*** 使用字符流写内容到文件，需要调用 close() 方法关闭流或者调用flush() 方法；* 转：在字符流的操作中，所有的字符都是在内存中形成的，在输出前会将所有的内容暂时保存在内存之中，所以使用了缓冲区暂存数据。* 如果想在不关闭时也可以将字符流的内容全部输出，则可以使用Writer类中的flush()方法完成*/outputStreamWriter.close();System.out.println("内容写入成功！");}

FileWriter 便捷字符输出流

/*** 便捷字符输出流* 将字符串写入到文件内*/public static void tFileWrite() throws Exception{FileWriter fileWriter = new FileWriter("src/b.txt");String str = "层峦耸翠，上出重霄；飞阁流丹，下临无地。鹤汀凫渚，穷岛屿之萦回；桂殿兰宫，即冈峦之体势。";fileWriter.write(str);fileWriter.close();System.out.println("内容写入成功！");}

BufferedWriter 字符缓冲输入流

/*** 字符缓冲输入流* 将字符串写入到文件内*/public static void tBufferWrite() throws Exception{BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter("src/b.txt"));String str = "云销雨霁，彩彻区明。落霞与孤鹜齐飞，秋水共长天一色。渔舟唱晚，响穷彭蠡之滨；雁阵惊寒，声断衡阳之浦。";bufferedWriter.write(str);bufferedWriter.close();System.out.println("内容写入成功！");}