字符流练习-基本用法掌握

import java.io.FileWriter;
import java.io.IOException;

/*
  * 演示字符输出流
 */
public class Demo04 {
	public static void main(String[] args) throws IOException {
		// 创建字符输入流对象
		FileWriter fw = new FileWriter("a.txt");
		fw.write("abc");
		fw.write("你好");

		fw.flush();
		fw.close();
	}
}

import java.io.FileReader;
import java.io.IOException;

/*
 * 演示字符输入流
 */
public class Demo05 {
	public static void main(String[] args) throws IOException {
		// 创建输入流对象
		FileReader fr = new FileReader("a.txt");
		char[] ch = new char[1024];
		int len = 0;
		while ((len = fr.read(ch)) != -1) {
			System.out.println(new String(ch, 0, len));
		}
		fr.close();
	}
}

import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import org.junit.Test;
/*
 * 使用字符流复制文件
 */
public class Demo06 {
	@Test
	public void test() throws IOException {
		//创建字符输入输出流
		FileReader fr = new FileReader("d:\\Demo3.java");
		FileWriter fw = new FileWriter("d:\\复制.java");
		
		char [] ch = new char [1024];
		int len = 0 ;
		while((len = fr.read(ch)) != -1) {
			fw.write(ch,0,len);
			fw.flush();
		}
		fr.close();
		fw.close();
				
	}
}

import java.io.IOException;
import java.net.URLDecoder;
import java.net.URLEncoder;
/*
 * 编码、解码、乱码
 */
public class Demo07 {
	public static void main(String[] args) throws IOException {
		// 准备好被编码的数据
		String s = "你好";

		// 编码
		byte[] by = s.getBytes("utf-8");

		// 解码
		String str = new String(by, "gbk");
		System.out.println(str);

		// 使用不一直的编码表导致乱码，
		// 使用gbk反编ma
		byte[] by2 = str.getBytes("gbk");

		// 使用utf-8进行解码
		String str2 = new String(by2, "utf-8");
		System.out.println(str2);
		
		
		//使用URLEncoder编码，使用URLDecoder解码
		
		String str3 = URLEncoder.encode(s,"gbk");
		String str4 = URLDecoder.decode(str3,"gbk");
		System.out.println(str3);
		System.out.println(str4);
	}
}

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

import org.junit.Test;

/*
 * 使用字符缓冲流复制文件
 */
public class Demo {
	@Test
	public void test() throws IOException {
		FileReader fr = new FileReader("d:\\Demo3.java");
		BufferedReader br = new BufferedReader(fr);
		
		FileWriter fw = new FileWriter("d:复制.java");
		BufferedWriter bw = new BufferedWriter(fw);
		
		String line = null;
		while((line =br.readLine()) != null ) {
			bw.write(line);
			bw.newLine();
		}
		br.close();
		bw.close();
	}
}