字节型

FileInputStream读取

package test;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.*;
public class Test {
    public static void main(String[] args) {
        FileInputStream stream = null;
        try {
            stream = new FileInputStream(new File("./abc.txt"));
            byte[] value = new byte[5]; // 利用byte[]的方式读取
            int count = stream.read(value);
            while (count != -1){
                System.out.print(new String(value,0,count));
                count = stream.read(value);
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                if (stream != null) {
                    stream.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
//        File file = new File("./abc.txt");
//        try {
//            FileInputStream stream = new FileInputStream(file);
//            int i = stream.read();
//            stream.available(); // 有多少字节可用
//
//            //byte[] value = new byte[5];
//            //stream.read(value); // 带byte[]参数的读取文件
//
//            stream.skip(3); // 跳过几个字节
//            while (i != -1) {
//                System.out.print((char) i);
//                i = stream.read(); // 读取文件
//            }
//            stream.close(); // 关闭流通道，必须关闭
//        } catch (IOException e) {
//            e.printStackTrace();
//        }
    }
}

FileOutputStream写入

package test;
import java.io.*;
import java.util.*;
public class Test {
    public static void main(String[] args) {
        String str = "abcd";
        FileOutputStream fos = null;
        try {
             // 如果没有这个文件就会自己创建
            fos = new FileOutputStream(new File("./abc.txt"), true); // 用追加的方式写入
            byte[] value = str.getBytes(); // 用byte[]的方法写 ，可以写入字节
            fos.write(value); // 写入
            fos.flush(); // 刷新
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                if (fos != null) {
                    fos.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}

字符型

FileRead读取 只能渡纯文本

package test;
import java.io.*;
import java.util.*;
public class Test {
    public static void main(String[] args) {
        File file = new File("./abc.txt");
        FileReader reader = null;
        try {
            reader = new FileReader(file);
            //int code = reader.read(); // 读取单个字符
            char[] chars = new char[1024];
            int count = reader.read(chars); // 使用char数组
            while (count != -1) {
                System.out.print(new String(chars,0 ,count));
                count = reader.read(chars);
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                if (reader != null) {
                    reader.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}

FileWirte写入

package test;
import java.io.*;
import java.util.*;
public class Test {
    public static void main(String[] args) {
        File file = new File("./abc.txt");
        FileReader reader = null;
        FileWriter writer = null;
        try {
            writer = new FileWriter(file,true);
            String str = "我擦撒娇撒";
            writer.write(str.toCharArray()); // char数组写入
            writer.write('a');
            writer.write(100); // char类型写入
            writer.write("我"); // 字符串类型写入
            writer.flush();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                if (writer != null) {
                    writer.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}