IOの利用字节流和字符流完成文件的复制demo

package IO;

import java.io.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;

import org.junit.Test;

//完成字符流和字节流的输入输出
public class TestExer {

// 字符流利用程序复制
@Test
public void test4() {
BufferedReader bufferedReader = null;
BufferedWriter bufferedWriter = null;
try {
bufferedReader = new BufferedReader(new FileReader("test1.txt"));
bufferedWriter = new BufferedWriter(new FileWriter("hadi.txt"));
char[] c = new char[20];
int len;
while ((len = bufferedReader.read(c)) != -1) {
bufferedWriter.write(c, 0, len);
}
bufferedWriter.flush();

} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} finally {
if (bufferedWriter != null) {
try {
bufferedWriter.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if (bufferedReader != null) {
try {
bufferedReader.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}

}

// 使用字符流实现内容的读入
@Test
public void test3() {
BufferedReader bufferedReader = null;
try {
bufferedReader = new BufferedReader(new FileReader("test.txt"));
String string;
while ((string = bufferedReader.readLine()) != null) {
System.out.println(string);
}

} catch (IOException e) {
e.printStackTrace();
} finally {
if (bufferedReader != null) {
try {
bufferedReader.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}

}

}

// 使用字符流实现内容输出
@Test
public void test2() {
BufferedWriter bufferedWriter = null;
try {
bufferedWriter = new BufferedWriter(new FileWriter(new File("test1.txt")));
// 可以直接写成这个：bufferedWriter = new BufferedWriter(new
// FileWriter("test1.txt"));
String string = "转换流：实现字节流与字符流之间的转换InputStreamReader输入时，\n" + "实现字节流到字符流的转换，提高操作的效率（前提是，数据是文本文件）\n"
+ "===>解码：从字节数组到字符串（相对于人能看懂了，所以叫解释了，解码）\n" + " ===>编码：从字符流到字节流（相对于人把文字变成了数字，看不懂了，叫编码）\n"
+ "OutputStreamWriter：输出时，实现字符流到字节流的转换。从看得懂到看不懂，\n"
+ "在底层用0101存储。 ===>编码：从字符流到字节流（相对于人把文字变成了数字，看不懂了，叫编码）\n"
+ "System.in:标准输入流：从键盘输入数据System.out:标准输出流：从显示器输出数据\n";

bufferedWriter.write(string);
bufferedWriter.flush();
} catch (IOException e) {
e.printStackTrace();
} finally {
if (bufferedWriter != null) {
try {
bufferedWriter.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}

}

// 使用字节流实现内容的输出
@Test
public void test1() {

// 处理流缓冲流的创建
BufferedOutputStream bufferedOutputStream = null;
try {
bufferedOutputStream = new BufferedOutputStream(new FileOutputStream(new File("test.txt")));

String string = "转换流：实现字节流与字符流之间的转换InputStreamReader输入时，\n" + "实现字节流到字符流的转换，提高操作的效率（前提是，数据是文本文件）\n"
+ "===>解码：从字节数组到字符串（相对于人能看懂了，所以叫解释了，解码）\n" + " ===>编码：从字符流到字节流（相对于人把文字变成了数字，看不懂了，叫编码）\n"
+ "OutputStreamWriter：输出时，实现字符流到字节流的转换。从看得懂到看不懂，\n"
+ "在底层用0101存储。 ===>编码：从字符流到字节流（相对于人把文字变成了数字，看不懂了，叫编码）\n"
+ "System.in:标准输入流：从键盘输入数据System.out:标准输出流：从显示器输出数据\n";

// 将一个字符串转化成字节数组，并写出到文件
bufferedOutputStream.write(string.getBytes());

} catch (IOException e1) {
e1.printStackTrace();
} finally {
if (bufferedOutputStream != null) {
// 关闭缓冲流，就会关闭相应的字节流
try {
bufferedOutputStream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}

}

}