IO操作

package cn.soldier.oop;

import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;

public class FileWriteAndReadDemo {
    private static String filePath = "E:\\ProgramCode\\demo.txt";

    public static void main(String[] args) {
        // 标准的文件流输出处理
        write();

        // 标准的文件流读入处理
        read();

        // 模拟一个文件拷贝
        copy();

    }

    /**
     * 标准的文件流输出处理
     * */
    private static void write() {
        FileWriter fileWriter = null;
        try {
            // 为true时追加写入字符
            fileWriter = new FileWriter(filePath, true);
            fileWriter.write("呵呵");
            fileWriter.flush();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                if (fileWriter != null) {
                    fileWriter.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    /**
     * 标准的文件流读入处理
     */
    private static void read() {
        FileReader fileReader = null;
        try {
            fileReader = new FileReader(filePath);
            char[] buff = new char[5];
            try {
                int num = 0;
                // 读取字符数组，每次读的个数是字符数组的长度，如果有足够的字符的话。
                while ((num = fileReader.read(buff)) != -1) {
                    System.out.println("num=" + num + "..."
                            + new String(buff, 0, num));
                }
                // 逐个字符读取
                // int ch = 0;
                // while ((ch = fileReader.read()) != -1) {
                // System.out.println((char) ch);
                // }
            } catch (IOException e) {
                e.printStackTrace();
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } finally {
            try {
                if (fileReader != null) {
                    fileReader.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    /**
     * 模拟一个文件拷贝
     * */
    private static void copy() {
        FileWriter fileWriter = null;
        FileReader fileReader = null;
        try {
            fileWriter = new FileWriter("FileWriteAndReadDemo.txt", true);
            fileReader = new FileReader(
                    "E:\\ProgramCode\\Java\\MyEclipse 10\\oop\\src\\cn\\soldier\\oop\\FileWriteAndReadDemo.java");

            // 字符数组方式读取
            char[] buff = new char[1024];
            int len = 0;
            while ((len = fileReader.read(buff)) != -1) {
                fileWriter.write(buff, 0, len);
                fileWriter.flush();
                System.out.println(len + "");
            }

            // 逐个字符读取
            // int ch = 0;
            // while ((ch = fileReader.read()) != -1) {
            // fileWriter.write(ch);
            // fileWriter.flush();
            // }
            System.out.println("读完了");

        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                if (fileWriter != null) {
                    fileWriter.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
            try {
                if (fileReader != null) {
                    fileReader.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }

        }
    }

}

package cn.soldier.oop;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;

public class BufferedWriterAndReaderDemo {
    private static String filePath = "E:\\ProgramCode\\demo.txt";

    public static void main(String[] args) {
        buffWrite();
        buffRead();
        buffCopy();
    }

    private static void buffCopy() {
        FileWriter fileWriter = null;
        BufferedWriter bufw = null;
        FileReader fileReader = null;
        BufferedReader bufr = null;

        try {
            fileWriter = new FileWriter("BufferedWriterAndReaderDemo.txt");
            bufw = new BufferedWriter(fileWriter);
            fileReader = new FileReader(
                    "E:\\ProgramCode\\Java\\MyEclipse 10\\oop\\src\\cn\\soldier\\oop\\BufferedWriterAndReaderDemo.java");
            bufr = new BufferedReader(fileReader);

            String line = null;

            while ((line = bufr.readLine()) != null) {
                bufw.write(line);
                bufw.newLine();
                bufw.flush();
            }
            System.out.println("end the copy");

        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                if (bufr != null) {
                    bufr.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }

            // 关闭缓冲区就是关闭流
            try {
                if (bufw != null) {
                    bufw.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

    }

    private static void buffRead() {
        FileReader fileReader = null;
        BufferedReader bufferedReader = null;
        try {
            fileReader = new FileReader(filePath);
            bufferedReader = new BufferedReader(fileReader);

            String line = null;
            try {
                while ((line = bufferedReader.readLine()) != null) {
                    System.out.println(line);
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } finally {
            if (bufferedReader != null) {
                try {
                    bufferedReader.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }

    private static void buffWrite() {
        FileWriter fileWriter = null;
        BufferedWriter bufw = null;
        try {
            fileWriter = new FileWriter(filePath);

            bufw = new BufferedWriter(fileWriter);

            for (int i = 1; i <= 1024; i++) {
                bufw.write(‘c‘);
                if (i % 100 == 0) {
                    bufw.newLine();
                }
            }

            bufw.flush();
            System.out.println("写入结束");
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            // 关闭缓冲区就是关闭流
            if (bufw != null) {
                try {
                    bufw.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }
}