DataInputStream(InputStream in)

DataOutputStream(OutputStream out) 

public class DataStreamDemo {public static void main(String[] args) throws IOException {// 写// write();// 读
        read();}private static void read() throws IOException {// DataInputStream(InputStream in)// 创建数据输入流对象DataInputStream dis = new DataInputStream(new FileInputStream("dos.txt"));// 读数据byte b = dis.readByte();short s = dis.readShort();int i = dis.readInt();long l = dis.readLong();float f = dis.readFloat();double d = dis.readDouble();char c = dis.readChar();boolean bb = dis.readBoolean();// 释放资源
        dis.close();System.out.println(b);System.out.println(s);System.out.println(i);System.out.println(l);System.out.println(f);System.out.println(d);System.out.println(c);System.out.println(bb);}private static void write() throws IOException {// DataOutputStream(OutputStream out)// 创建数据输出流对象DataOutputStream dos = new DataOutputStream(new FileOutputStream("dos.txt"));// 写数据dos.writeByte(10);dos.writeShort(100);dos.writeInt(1000);dos.writeLong(10000);dos.writeFloat(12.34F);dos.writeDouble(12.56);dos.writeChar('a');dos.writeBoolean(true);// 释放资源
        dos.close();}
}

public class ByteArrayStreamDemo {public static void main(String[] args) throws IOException {// 写数据// ByteArrayOutputStream()ByteArrayOutputStream baos = new ByteArrayOutputStream();for (int x = 0; x < 10; x++) {baos.write(("hello" + x).getBytes());}// 释放资源// 通过查看源码我们知道这里什么都没做，所以根本需要close()// baos.close();// public byte[] toByteArray()byte[] bys = baos.toByteArray();// 读数据// ByteArrayInputStream(byte[] buf)ByteArrayInputStream bais = new ByteArrayInputStream(bys);int by = 0;while ((by = bais.read()) != -1) {System.out.print((char) by);}}
}

public class PrintWriterDemo {public static void main(String[] args) throws IOException {// 创建打印流对象// PrintWriter pw = new PrintWriter("pw.txt");// 开启自动刷新PrintWriter pw = new PrintWriter(new FileWriter("pw.txt"), true);// write只能操作字符串/*pw.write("hello");pw.write("world");pw.write("java");*/// 要操作任意类型的数据,要使用print()或println()/*pw.print(true);pw.print(100);pw.print("hello");*/// 使用print()操作数据后,如果没有调用close(),数据是不会自动刷新的// 使用println(),并且使用public PrintWriter(Writer out,boolean autoFlush)构造方法后,就能使用自动刷新了,即使不调用close(),数据也能写入到文件// 此时的println()相当于write()+newLine()+flush()三个方法的综合pw.println(true);pw.println(100);pw.println("hello");// pw.close();
    }
}

/*** 需求：PrintWriterDemo.java复制到Copy.java中* 数据源：*         DataStreamDemo.java -- 读取数据 -- FileReader -- BufferedReader* 目的地：*         Copy.java -- 写出数据 -- FileWriter -- BufferedWriter -- PrintWriter*/
public class CopyFileDemo {public static void main(String[] args) throws IOException {// 以前的版本/*BufferedReader br = new BufferedReader(new FileReader("PrintWriterDemo.java"));// 封装目的地BufferedWriter bw = new BufferedWriter(new FileWriter("Copy.java"));String line = null;while ((line = br.readLine()) != null) {bw.write(line);bw.newLine();bw.flush();}bw.close();br.close();*/// 打印流的改进版// 封装数据源BufferedReader br = new BufferedReader(new FileReader("PrintWriterDemo.java"));// 封装目的地PrintWriter pw = new PrintWriter(new FileWriter("Copy.java"), true);String line = null;while ((line = br.readLine()) != null) {pw.println(line);}pw.close();br.close();}
}

public class SystemOutDemo {public static void main(String[] args) {// 有这里的讲解我们就知道了，这个输出语句其本质是IO流操作，把数据输出到控制台。System.out.println("helloworld");// 获取标准输出流对象PrintStream ps = System.out;ps.println("helloworld");ps.println();// ps.print();//这个方法不存在
System.out.println();// System.out.print();//这是错误的
    }
}

public class SystemOutDemo2 {public static void main(String[] args) throws IOException {// 获取标准输出流// PrintStream ps = System.out;// OutputStream os = ps;// OutputStream os = System.out;//多态// 我能不能按照刚才使用标准输入流的方式一样把数据输出到控制台呢？// OutputStreamWriter osw = new OutputStreamWriter(os);// BufferedWriter bw = new BufferedWriter(osw);BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));bw.write("hello");bw.newLine();bw.write("world");bw.newLine();bw.write("java");bw.newLine();bw.flush();bw.close();}
}

public class SystemInDemo {public static void main(String[] args) throws IOException {BufferedReader br = new BufferedReader(new InputStreamReader(System.in));System.out.println("请输入一个字符串：");String line = br.readLine();System.out.println("你输入的字符串是：" + line);System.out.println("请输入一个整数：");line = br.readLine();int i = Integer.parseInt(line);System.out.println("你输入的整数是：" + i);}
}

public class RandomAccessFileDemo {public static void main(String[] args) throws IOException {// write();
        read();}private static void read() throws IOException {// 创建随机访问流对象RandomAccessFile raf = new RandomAccessFile("raf.txt", "rw");int i = raf.readInt();System.out.println(i);// 该文件指针可以通过 getFilePointer方法读取，并通过 seek 方法设置。System.out.println("当前文件的指针位置是：" + raf.getFilePointer());char ch = raf.readChar();System.out.println(ch);System.out.println("当前文件的指针位置是：" + raf.getFilePointer());String s = raf.readUTF();System.out.println(s);System.out.println("当前文件的指针位置是：" + raf.getFilePointer());// 我不想重头开始了，我就要读取a，怎么办呢?raf.seek(4);ch = raf.readChar();System.out.println(ch);}private static void write() throws IOException {// 创建随机访问流对象RandomAccessFile raf = new RandomAccessFile("raf.txt", "rw");// 怎么玩呢?raf.writeInt(100);raf.writeChar('a');raf.writeUTF("中国");raf.close();}
}

/** 以前的操作：* a.txt -- b.txt* c.txt -- d.txt* * 现在想要：* a.txt+b.txt -- c.txt*/
public class SequenceInputStreamDemo {public static void main(String[] args) throws IOException {// SequenceInputStream(InputStream s1, InputStream s2)// 需求：把ByteArrayStreamDemo.java和DataStreamDemo.java的内容复制到Copy.java中InputStream s1 = new FileInputStream("ByteArrayStreamDemo.java");InputStream s2 = new FileInputStream("DataStreamDemo.java");SequenceInputStream sis = new SequenceInputStream(s1, s2);BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream("Copy.java"));// 如何写读写呢，其实很简单，你就按照以前怎么读写，现在还是怎么读写byte[] bys = new byte[1024];int len = 0;while ((len = sis.read(bys)) != -1) {bos.write(bys, 0, len);}bos.close();sis.close();}
}

/** 以前的操作：* a.txt -- b.txt* c.txt -- d.txt* e.txt -- f.txt* * 现在想要：* a.txt+b.txt+c.txt -- d.txt*/
public class SequenceInputStreamDemo2 {public static void main(String[] args) throws IOException {// 需求：把下面的三个文件的内容复制到Copy.java中// ByteArrayStreamDemo.java,CopyFileDemo.java,DataStreamDemo.java// SequenceInputStream(Enumeration e)// 通过简单的回顾我们知道了Enumeration是Vector中的一个方法的返回值类型。// Enumeration<E> elements()Vector<InputStream> v = new Vector<InputStream>();InputStream s1 = new FileInputStream("ByteArrayStreamDemo.java");InputStream s2 = new FileInputStream("CopyFileDemo.java");InputStream s3 = new FileInputStream("DataStreamDemo.java");v.add(s1);v.add(s2);v.add(s3);Enumeration<InputStream> en = v.elements();SequenceInputStream sis = new SequenceInputStream(en);BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream("Copy.java"));// 如何写读写呢，其实很简单，你就按照以前怎么读写，现在还是怎么读写byte[] bys = new byte[1024];int len = 0;while ((len = sis.read(bys)) != -1) {bos.write(bys, 0, len);}bos.close();sis.close();}
}

public class Person implements Serializable {private String name;private int age;public Person() {}public Person(String name, int age) {this.name = name;this.age = age;}public String getName() {return name;}public void setName(String name) {this.name = name;}public int getAge() {return age;}public void setAge(int age) {this.age = age;}@Overridepublic String toString() {return "Person{" +"name='" + name + '\'' +", age=" + age +'}';}
}

public class ObjectStreamDemo {public static void main(String[] args) throws IOException, ClassNotFoundException {// 序列化数据其实就是把对象写到文本文件// write();
read();}private static void read() throws IOException, ClassNotFoundException {// 创建反序列化对象ObjectInputStream ois = new ObjectInputStream(new FileInputStream("oos.txt"));// 还原对象Object object = ois.readObject();// 释放资源
        ois.close();// 输出对象
        System.out.println(object);}private static void write() throws IOException {// 创建序列化流对象ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream("oos.txt"));// 创建对象Person person = new Person("林青霞", 27);// public final void writeObject(Object obj)
        oos.writeObject(person);// 释放资源
        oos.close();}
}

public class Person implements Serializable {private String name;int age;...
}