其他流（常用非基本流）

包装流，也叫缓冲流，高效流

字符输出流，内置数组[1024]

缓冲字节流内置数组[8192]

转换流（本身是字符流）是字节流到字符流的桥梁

idea默认UTF8编码,而eclipse是gbk

序列化

注意：序列化对象所在类需先实现Serializable接口

重点：

IO流file，四种基本流

缓冲流buffer，通过缓冲区读写，减少系统IO次数(输入输出次数)，从而提高读写的效率。

转换流input/output，解决不同编码的文件转换问题

序列化object，节序列,写出到文件之后，相当于,文件中持久保存了一个对象的信息；反之，该字节序列,还可以从文件中读取回来，重构对象，对它进行反序列化。

序列化举例

import java.io.*;
import java.util.ArrayList;
 
public class Test05 {
public static void main(String[] args) throws Exception {
//将对象写入文件
//ArrayList<Student> al = new ArrayList();
//al.add(new Student("fbb",18));
//al.add(new Student("zwj", 20));
//
//ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream("day20\\c.txt"));
//oos.writeObject(al);
//
//oos.close();
 
//从文件中读取对象
ObjectInputStream ois = new ObjectInputStream(new FileInputStream("day20\\c.txt"));
ArrayList<Student> al = (ArrayList<Student>) ois.readObject();
 
ois.close();
 
for (Student student : al) {
System.out.println(student.getName() + student.getAge());
}
}
}
 
class Student implements Serializable { //序列化对象所在类需先实现Serializable接口
private String name;
//private transient int age; //transient瞬时的，无法序列化，不能永久保存
private int age;
private String address;//写入文本后加的成员变量，此时类的class文件已更改，要再次将对象读取到内存，需记录下之前序列号
public static final long serialVersionUID = 6845409090868647L; //将一开始的class文件的序列号记录为一个静态成员常量
 
public Student() {
}
 
public Student(String name, int age, String address) {
this.name = name;
this.age = age;
this.address = address;
}
 
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;
}
 
public String getAddress() {
return address;
}
 
public void setAddress(String address) {
this.address = address;
}
 
@Override
public String toString() {
return "Student{" +
"name='" + name + '\'' +
", age=" + age +
", address='" + address + '\'' +
'}';
}
}

下面是一些代码：

//缓冲字节流
import java.io.*;

public class Test01 {
    public static void main(String[] args) throws Exception {
        File f = new File("day20\\b.wmv");
        f.delete();

        FileInputStream fis = new FileInputStream("day20\\a.wmv");
        FileOutputStream fos = new FileOutputStream("day20\\b.wmv");

        BufferedInputStream bis = new BufferedInputStream(fis);
        BufferedOutputStream bos = new BufferedOutputStream(fos);

        long start = System.currentTimeMillis();

        int ch;
        byte[] arr = new byte[1024];
        while ((ch = bis.read(arr)) != -1) {
            bos.write(arr, 0, ch);
        }

        long end = System.currentTimeMillis();

        bos.close();//同时也关闭了它所包装的fos
bis.close();//同时也关闭了它所包装的fis

        //fos.close();
        //fis.close();

System.out.println(end - start);
    }
}

//缓冲字符流
//对每一段以“1.先帝创业...”形式开头的出师表进行排序，输出到一个新文本文件中
import java.io.*;
import java.util.HashMap;

public class Test02 {
    public static void main(String[] args) throws Exception {
        BufferedReader br = new BufferedReader(new FileReader("day20\\a.txt"));
        HashMap<String,String> hm = new HashMap();
        String ch;
        while ((ch = br.readLine()) != null) {
            String[] split = ch.split("\\.");
            hm.put(split[0], split[1]);
        }

        br.close();

        BufferedWriter bw = new BufferedWriter(new FileWriter("day20\\aa.txt"));

        String key = null;
        for (int i = 1; i <= hm.size(); i++) {
            key = ""+i;
            bw.write(key + "." + hm.get(key));
            bw.newLine();
        }

        bw.close();
    }
}
上一个代码可改写：
import java.io.*;
import java.util.ArrayList;
import java.util.Collections;

public class Test03 {
    public static void main(String[] args) throws Exception {
        FileReader fr = new FileReader("day20\\a.txt");
        BufferedReader br = new BufferedReader(fr);

        ArrayList<String> al = new ArrayList();

        String ch;
        while ((ch = br.readLine()) != null) {
            al.add(ch);
        }

        br.close();

        Collections.sort(al);
        BufferedWriter bw = new BufferedWriter(new FileWriter("day20\\aaa.txt"));
        for (String s : al) {
            bw.write(s);
            bw.newLine();
        }
        bw.close();
    }
}

//打印流，用途不大
import java.io.FileOutputStream;
import java.io.PrintStream;

public class Test06 {
    public static void main(String[] args) throws Exception {
        PrintStream ps = new PrintStream(new FileOutputStream("day20\\d.txt"));
        ps.println(666);
        ps.write(97);
        System.setOut(ps);//改变打印流向
System.out.println(985);
    }
}