IOTest-InputStream-OutputStream

 

 

 

//大文件复制 包装前后 时间测试
@Test
public void copyTest() throws Exception{
long start = System.currentTimeMillis();
//读取文件c:\centos.iso
FileInputStream fis = new FileInputStream("c:\\centos.iso");
BufferedInputStream bis = new BufferedInputStream(fis);
FileOutputStream fos = new FileOutputStream("d:\\cent.iso");
BufferedOutputStream bos = new BufferedOutputStream(fos);
int len = 0;
byte[] buf = new byte[4096];
while((len = bis.read(buf))!=-1){
bos.write(buf, 0, len);
}
bis.close();
bos.close();
long end = System.currentTimeMillis();
System.out.println("复制所用时间："+(end - start));//1024-11592 //4096-8046
}

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//复制文件c:\hz.txt 到 d:hz2.txt
@Test
public void copyFile() throws IOException{
//首先创建一个hz.txt文件在c盘
File f = new File("c:\\hz.txt");
f.createNewFile();
//向文件当中写入数据
String str = "Hello 你好 Java \r\n";
Writer wr = new FileWriter(f,true);
// wr.write(str);
// wr.flush();
// wr.close();
//读取文件到内存 并写入d盘
Reader rd = new FileReader(f);
int len = 0;
char[] buf = new char[1024];
while((len = rd.read(buf))!=-1){
wr = new FileWriter("d:\\hz2.txt",true);
// wr.write(buf, 0, len);
wr.write(new String(buf));
}
wr.flush();
wr.close();
}

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public class IOTest {
static File f = new File("a.txt");
public static void main(String[] args) {
m2();
}
public static void m2(){
InputStream in = null;
int len = 0;
byte[] buf;
buf = new byte[100];
try {
in = new FileInputStream(f);//读取文件
len = in.read(buf);
System.out.println(len);//读取的内容长度
System.out.println(new String(buf));//读取的内容
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
public static void m1(){
OutputStream out = null;
String str = "ABC012国\n";
byte[] buf = null;
try {
buf = str.getBytes("utf-8");//把写入内容指定字符集 防止乱码
//out = new FileOutputStream(f);//覆盖写入文件
out = new FileOutputStream(f,true);//追加写入文件
out.write(buf);
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}finally{
try {
out.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}//main