文件读写回顾

文件读写方法
1、字节读写（InputStream/OutputStream）
2、字符读取（FileReader/FileWriter）
3、行读取（BufferedReader/BufferedWriter）

package com.waddell.basic;  import java.io.BufferedReader;  import java.io.BufferedWriter;  import java.io.File;  import java.io.FileInputStream;  import java.io.FileOutputStream;  import java.io.FileReader;  import java.io.FileWriter;  import java.io.IOException;  import java.io.InputStream;  import java.io.OutputStream;  import java.nio.ByteBuffer;  import java.nio.channels.FileChannel;  public class FileOperate {      private static final String FILE_PATH = "d:/work/jipinwodi.txt";      /**      * 以字节为单位读写文件内容      *       * @param filePath      *            ：需要读取的文件路径      */      public static void readFileByByte(String filePath) {          File file = new File(filePath);          // InputStream:此抽象类是表示字节输入流的所有类的超类。          InputStream ins = null;          OutputStream outs = null;          try {              // FileInputStream:从文件系统中的某个文件中获得输入字节。              ins = new FileInputStream(file);              outs = new FileOutputStream("d:/work/readFileByByte.txt");              int temp;              // read():从输入流中读取数据的下一个字节。              while ((temp = ins.read()) != -1) {                  outs.write(temp);              }          } catch (Exception e) {              e.getStackTrace();          } finally {              if (ins != null && outs != null) {                  try {                      outs.close();                      ins.close();                  } catch (IOException e) {                      e.getStackTrace();                  }              }          }      }      /**      * 以字符为单位读写文件内容      *       * @param filePath      */      public static void readFileByCharacter(String filePath) {          File file = new File(filePath);          // FileReader:用来读取字符文件的便捷类。          FileReader reader = null;          FileWriter writer = null;          try {              reader = new FileReader(file);              writer = new FileWriter("d:/work/readFileByCharacter.txt");              int temp;              while ((temp = reader.read()) != -1) {                  writer.write((char)temp);              }          } catch (IOException e) {              e.getStackTrace();          } finally {              if (reader != null && writer != null) {                  try {                      reader.close();                      writer.close();                  } catch (IOException e) {                      e.printStackTrace();                  }              }          }      }      /**      * 以行为单位读写文件内容      *       * @param filePath      */      public static void readFileByLine(String filePath) {          File file = new File(filePath);          // BufferedReader:从字符输入流中读取文本，缓冲各个字符，从而实现字符、数组和行的高效读取。          BufferedReader bufReader = null;          BufferedWriter bufWriter = null;          try {              // FileReader:用来读取字符文件的便捷类。              bufReader = new BufferedReader(new FileReader(file));              bufWriter = new BufferedWriter(new FileWriter("d:/work/readFileByLine.txt"));              // buf = new BufferedReader(new InputStreamReader(new              // FileInputStream(file)));              String temp = null;              while ((temp = bufReader.readLine()) != null) {                  bufWriter.write(temp+"\n");              }          } catch (Exception e) {              e.getStackTrace();          } finally {              if (bufReader != null && bufWriter != null) {                  try {                      bufReader.close();                      bufWriter.close();                  } catch (IOException e) {                      e.getStackTrace();                  }              }          }      }      /**      * 使用Java.nio ByteBuffer字节将一个文件输出至另一文件      *       * @param filePath      */      public static void readFileByBybeBuffer(String filePath) {          FileInputStream in = null;          FileOutputStream out = null;          try {              // 获取源文件和目标文件的输入输出流                in = new FileInputStream(filePath);              out = new FileOutputStream("d:/work/readFileByBybeBuffer.txt");              // 获取输入输出通道              FileChannel fcIn = in.getChannel();              FileChannel fcOut = out.getChannel();              ByteBuffer buffer = ByteBuffer.allocate(1024);              while (true) {                  // clear方法重设缓冲区，使它可以接受读入的数据                  buffer.clear();                  // 从输入通道中将数据读到缓冲区                  int r = fcIn.read(buffer);                  if (r == -1) {                      break;                  }                  // flip方法让缓冲区可以将新读入的数据写入另一个通道                    buffer.flip();                  fcOut.write(buffer);              }          } catch (Exception e) {              e.printStackTrace();          } finally {              if (in != null && out != null) {                  try {                      in.close();                      out.close();                  } catch (IOException e) {                      e.printStackTrace();                  }              }          }      }      public static long getTime(){          return System.currentTimeMillis();      }      public static void main(String args[]) {          long time1 = getTime() ;          // readFileByByte(FILE_PATH);// 8734,8281,8000,7781,8047          // readFileByCharacter(FILE_PATH);// 734, 437, 437, 438, 422          // readFileByLine(FILE_PATH);// 110, 94,  94,  110, 93          readFileByBybeBuffer(FILE_PATH);// 125, 78,  62,  78, 62          long time2 = getTime() ;          System.out.println(time2-time1);      }  }