最近在看NIO,顺便总结一下IO的使用。
一、InputStream、OutputStream(字节流)
//读取文件(字节流) InputStream in = new FileInputStream("d:\\1234.txt"); //写入相应的文件 OutputStream out = new FileOutputStream("d:\\2134.txt"); //读取数据 //一次性取多少字节 byte[] bytes = new byte[1024]; //接受读取的内容(n就代表的相关数据,只不过是数字的形式) int n = -1; //循环取出数据 while ((n = in.read(bytes,0,bytes.length)) != -1) { //转换成字符串 String str = new String(bytes,0,n,"GBK"); System.out.println(str); //写入相关文件 out.write(bytes, 0, n); } //关闭流 in.close(); out.close();
二、BufferedInputStream、BufferedOutputStream(缓存字节流)使用方式和字节流差不多,但是效率更高(推荐使用)
//读取文件(缓存字节流) BufferedInputStream in = new BufferedInputStream(new FileInputStream("d:\\1234.txt")); //写入相应的文件 BufferedOutputStream out = new BufferedOutputStream(new FileOutputStream("d:\\2134.txt")); //读取数据 //一次性取多少字节 byte[] bytes = new byte[1024]; //接受读取的内容(n就代表的相关数据,只不过是数字的形式) int n = -1; //循环取出数据 while ((n = in.read(bytes,0,bytes.length)) != -1) { //转换成字符串 String str = new String(bytes,0,n,"GBK"); System.out.println(str); //写入相关文件 out.write(bytes, 0, n); } //清楚缓存 out.flush(); //关闭流 in.close(); out.close();
三、InputStreamReader、OutputStreamWriter(字节流,这种方式不建议使用,不能直接字节长度读写)。使用范围用做字符转换
//读取文件(字节流) InputStreamReader in = new InputStreamReader(new FileInputStream("d:\\1234.txt"),"GBK"); //写入相应的文件 OutputStreamWriter out = new OutputStreamWriter(new FileOutputStream("d:\\2134.txt")); //读取数据 //循环取出数据 byte[] bytes = new byte[1024]; int len = -1; while ((len = in.read()) != -1) { System.out.println(len); //写入相关文件 out.write(len); } //清楚缓存 out.flush(); //关闭流 in.close(); out.close();
四、BufferedReader、BufferedWriter(缓存流,提供readLine方法读取一行文本)
//读取文件(字符流) BufferedReader in = new BufferedReader(new InputStreamReader(new FileInputStream("d:\\1234.txt"),"GBK")); //写入相应的文件 BufferedWriter out = new BufferedWriter(new OutputStreamWriter(new FileOutputStream("d:\\2134.txt"),"GBK")); //读取数据 //循环取出数据 String str = null; while ((str = in.readLine()) != null) { System.out.println(str); //写入相关文件 out.write(str); out.newLine(); } //清楚缓存 out.flush(); //关闭流 in.close(); out.close();
五、Reader、PrintWriter(PrintWriter这个很好用,在写数据的同事可以格式化)
//读取文件(字节流) Reader in = new InputStreamReader(new FileInputStream("d:\\1234.txt"),"GBK"); //写入相应的文件 PrintWriter out = new PrintWriter(new FileWriter("d:\\2134.txt")); //读取数据 //循环取出数据 byte[] bytes = new byte[1024]; int len = -1; while ((len = in.read()) != -1) { System.out.println(len); //写入相关文件 out.write(len); } //清楚缓存 out.flush(); //关闭流 in.close(); out.close();
个人建议:流里面的读写,建议使用BufferedInputStream、BufferedOutputStream