千峰逆战班，Day32

在千峰“逆战班”学习的第32天
今天的学习内容是字符流，包括字符流的父类Reader、Writer，字符节点流FileWrite、FileReader，桥转换流InputStreamReader、OutputStreamWriter，以及字符过滤流中的缓冲流和printWriter，还有File类中的方法和FileFilter接口
中国加油！武汉加油！千峰加油！我自己加油！！

作业：
1.ABC
2.

		file = new File("hello.txt");
		if(file.exists()){
			System.out.println(file.getAbsolutePath());
		}

10.A：可以一次性将多个字符写入输出流
B：封装print()/println()方法，支持写入后换行
C:可以将字节流转换成字符流，可以设置字符的编码方式

11.字符流：.java源文件 .html网页文件；字节流：.class字节码文件 .jpg图像文件 .mp3音乐文件

12.ObjectInputStream：字节流、读八种基本类型、读对象
ObjectOutputStream：字节流、写八中基本类型、写对象
BufferInputStream：字节流、读八种基本类型、缓冲功能
BufferedOutputStream：字节流、写八中基本类型、缓冲功能
DataInputStream：字节流、读八种基本类型
DataOutputStream：字节流、写八中基本类型
PrintWrite：字符流、写字符串并换行
PrintStream：字节流
BufferedReader：字符流、缓冲功能、读入一行文本
14.

public class Question14 {
	public static void main(String[] args) throws IOException {
		
		InputStream is = new FileInputStream("test.txt");
		InputStreamReader isr = new InputStreamReader(is,"UTF-8");
		BufferedReader br = new BufferedReader(isr);
		OutputStream os = new FileOutputStream("test2.txt");
		OutputStreamWriter osw = new OutputStreamWriter(os,"UTF-8");
		PrintWriter pw = new PrintWriter(osw);
		while(true){
			String s = br.readLine();
			if(s == null){
				break;
			}
			pw.println(s);
		}
		pw.flush();
		br.close();
		pw.close();
	
	}
}

public class Question17 {
	public static void main(String[] args) throws IOException {
		Scanner sc = new Scanner(System.in);
		OutputStream os = new FileOutputStream("worldcup.txt");
		OutputStreamWriter osw = new OutputStreamWriter(os);
		PrintWriter pw = new PrintWriter(osw);
		pw.println("2006/意大利");
		pw.println("2002/巴西");
		pw.println("1998/法国");
		pw.println("1994/巴西");
		pw.println("1990/德国");
		pw.println("1986/阿根廷");
		pw.println("1982/意大利");
		pw.println("1978/阿根廷");
		pw.println("1974/德国");
		pw.println("1970/巴西");
		pw.println("1966/英格兰");
		pw.println("1962/巴西");
		pw.println("1958/巴西");
		pw.println("1954/德国");
		pw.println("1950/乌拉圭");
		pw.println("1938/意大利");
		pw.println("1934/意大利");
		pw.println("1930/乌拉圭");
		pw.flush();
		pw.close();
		InputStream is = new FileInputStream("worldcup.txt");
		InputStreamReader isr = new InputStreamReader(is);
		BufferedReader br = new BufferedReader(isr);
		System.out.println("请输入一个年份：");
		String year = sc.next();
		while(true){
			String s = br.readLine();
			if(s == null){
				System.out.println("没有举办世界杯");
				break;
			}
			if(s.startsWith(year)){
				char[] c = s.toCharArray();
				for(int i = s.indexOf("/") + 1; i <c.length;i++){
					System.out.print(c[i]);
				}
				break;
			}
			
		}
		
		
	}
}

public class Question18 {
	public static void main(String[] args) throws IOException {
		Scanner sc= new Scanner(System.in);
		System.out.println("请输入文件名：");
		String s = sc.next();
		
		File file = new File(s);
		if(file.exists()){
			InputStream is = new FileInputStream(s);
			InputStreamReader isr = new InputStreamReader(is);
			BufferedReader br = new BufferedReader(isr);
			
			OutputStream os = new FileOutputStream("copy_" + file.getName());
			OutputStreamWriter osw = new OutputStreamWriter(os);
			PrintWriter pw = new PrintWriter(osw);
			while(true){
				String s1 = br.readLine();
				if(s1 == null){
					break;
				}
				pw.println(s1);
			}
			pw.flush();
			br.close();
			pw.close();
			
		}else{
			System.out.println("该文件不存在");
		}
		
	}
}