一、IO流介绍
字节流： 输入流：InputStream 方法： read(byte[] b) 从输入流中读取一定数量的字节，并将其存储在缓冲区数组 b 中。
输出流：OutPutStream write(byte[] b, int off, int len) 将指定 byte 数组中从偏移量 off 开始的 len 个字节写入此输出流。 字符流： 输入流：Reader 输出流：Writer
二、InputStream 文件读取
public static void inputStreamMethod(){
File f = new File("F:\\z暂存文件\\test.txt");
InputStream inputStream = null;
try {
inputStream = new FileInputStream(f);
byte[] car = new byte[10];
//接收实际读取大小
int len = 0;
while ((len = inputStream.read(car))!=-1) {
//输出、字节数组转成字符串
String info = new String(car,0,len);
System.out.println(info);
}
} catch (FileNotFoundException e) {
e.printStackTrace();
System.out.println("文件不存在");
} catch (IOException e) {
e.printStackTrace();
System.out.println("文件读取失败");
} finally {
if(inputStream != null) {
try {
inputStream.close();
} catch (IOException e) {
e.printStackTrace();
System.out.println("流关闭失败");
}
}
}
}
三、OutPutStream文件输出
public static void outputStreamMethod() {
File f = new File("F:\\z暂存文件\\test.txt");
OutputStream os = null;
try {
//追加形式、否则默认是覆盖
os = new FileOutputStream(f,true);
//操作
String str = "\r\n这是即将要输出去的字符串1";
//字符串转字节数组
os.write(str.getBytes("utf-8"));
//强制刷新
os.flush();
} catch (FileNotFoundException e) {
e.printStackTrace();
System.out.println("文件找不到");
} catch (UnsupportedEncodingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
System.out.println("文件写出失败");
} finally {
if(os!=null) {
try {
os.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
四、文件复制
public static void fileCopy() {
SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss:sss");
Date start = new Date();
System.out.println("start time:"+df.format(start));
//源头文件 F:\\z暂存文件\\test.txt
File inFile = new File("D:\\DevelopmentTools\\VM\\os\\CentOS-7-x86_64-DVD-1611.iso");
//目的地文件
File outFile = new File("F:\\z暂存文件\\CentOS-7-x86_64-Minimal-1511.iso");
if(outFile.exists()) {
outFile.mkdirs();
}
InputStream inStream = null;
OutputStream oStream = null;
try {
inStream = new FileInputStream(inFile);
oStream = new FileOutputStream(outFile);
byte[] by = new byte[1024];
int len = 0;
while ((len = inStream.read(by))!=-1) {
//String s = new String(by);
//System.out.println(s);
oStream.write(by, 0, len);
}
oStream.flush();
} catch (FileNotFoundException e) {
e.printStackTrace();
System.out.println("上传文件找不到");
} catch (IOException e) {
e.printStackTrace();
System.out.println("文件处理异常");
} finally {
if(oStream!=null) {
try {
oStream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if(inStream!=null) {
try {
inStream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
Date end = new Date();
System.out.println("end time:"+df.format(end));
System.out.println("total time:"+(end.getTime()-start.getTime()));
}
平行世界，多元生活，愿你我既可以朝九晚五，又能够浪迹天涯。
– 《好吗好的》
