JAVA------IO流复制总结
IO流复制文件
方法一
字符
注意点：写和读需要保持一致的编码形式。
public class eee {
public static void main(String[] args) {
FileInputStream in = null;
FileOutputStream out = null;
OutputStreamWriter outw = null;
InputStreamReader inr = null;
try{
out = new FileOutputStream("D:\\远程\\11.txt");
in = new FileInputStream("D:\\远程\\22.txt");
outw = new OutputStreamWriter(out,"UTF-8");
inr = new InputStreamReader(in,"UTF-8");
int len = 0;
char[] c = new char[1024];
while((len=inr.read(c))!=-1){
outw.write(c, 0, len);
}
}catch(IOException ex){
System.out.println(ex);
throw new RuntimeException("文件写入失败,重试");
}finally{
try{
if(outw!=null)
out.flush();
outw.close();
}catch(IOException e){
throw new RuntimeException("关闭资源失败");
}finally{
try{
if(inr!=null){
inr.close();
}
}catch(IOException ea){
throw new RuntimeException("关闭资源失败");
}
}
}
}
}
方法二
/*
* 将数据源 c:\\a.txt
* 复制到 d:\\a.txt 数据目的
* 字节输入流,绑定数据源
* 字节输出流,绑定数据目的
*
* 输入,读取1个字节
* 输出,写1个字节
*/
public class Copy {
public static void main(String[] args) {
//定义两个流的对象变量
FileInputStream fis = null;
FileOutputStream fos = null;
try{
//建立两个流的对象,绑定数据源和数据目的
fis = new FileInputStream("c:\\t.zip");
fos = new FileOutputStream("d:\\t.zip");
//字节输入流,读取1个字节,输出流写1个字节
int len = 0 ;
while((len = fis.read())!=-1){
fos.write(len);
}
}catch(IOException ex){
System.out.println(ex);
throw new RuntimeException("文件复制失败");
}finally{
try{
if(fos!=null)
fos.close();
}catch(IOException ex){
throw new RuntimeException("释放资源失败");
}finally{
try{
if(fis!=null)
fis.close();
}catch(IOException ex){
throw new RuntimeException("释放资源失败");
}
}
}
}
}
方法二可以参考：
public static void main(String[] args) throws IOException {
FileInputStream fis = new FileInputStream("c:\\a.txt");
//创建字节数组
byte[] b = new byte[1024];
int len = 0 ;
while( (len = fis.read(b)) !=-1){
System.out.print(new String(b,0,len));
}
fis.close();
}
方法三
/*
* 字符流复制文本文件,必须文本文件
* 字符流查询本机默认的编码表,简体中文GBK
* FileReader读取数据源
* FileWriter写入到数据目的
*/
public class Copy_2 {
public static void main(String[] args) {
FileReader fr = null;
FileWriter fw = null;
try{
fr = new FileReader("c:\\1.txt");
fw = new FileWriter("d:\\1.txt");
char[] cbuf = new char[1024];
int len = 0 ;
while(( len = fr.read(cbuf))!=-1){
fw.write(cbuf, 0, len);
fw.flush();
}
}catch(IOException ex){
System.out.println(ex);
throw new RuntimeException("复制失败");
}finally{
try{
if(fw!=null)
fw.close();
}catch(IOException ex){
throw new RuntimeException("释放资源失败");
}finally{
try{
if(fr!=null)
fr.close();
}catch(IOException ex){
throw new RuntimeException("释放资源失败");
}
}
}
}
}
知识点
缓冲流
字节缓冲流
/*
* 文件复制方式,字节流,一共4个方式
* 1. 字节流读写单个字节 125250 毫秒
* 2. 字节流读写字节数组 193 毫秒 OK
* 3. 字节流缓冲区流读写单个字节 1210 毫秒
* 4. 字节流缓冲区流读写字节数组 73 毫秒 OK
*/
public class Copy {
public static void main(String[] args)throws IOException {
long s = System.currentTimeMillis();
copy_4(new File("c:\\q.exe"), new File("d:\\q.exe"));
long e = System.currentTimeMillis();
System.out.println(e-s);
}
/*
* 方法,实现文件复制
* 4. 字节流缓冲区流读写字节数组
*/
public static void copy_4(File src,File desc)throws IOException{
BufferedInputStream bis = new BufferedInputStream(new FileInputStream(src));
BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(desc));
int len = 0 ;
byte[] bytes = new byte[1024];
while((len = bis.read(bytes))!=-1){
bos.write(bytes,0,len);
}
bos.close();
bis.close();
}
/*
* 方法,实现文件复制
* 3. 字节流缓冲区流读写单个字节
*/
public static void copy_3(File src,File desc)throws IOException{
BufferedInputStream bis = new BufferedInputStream(new FileInputStream(src));
BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(desc));
int len = 0 ;
while((len = bis.read())!=-1){
bos.write(len);
}
bos.close();
bis.close();
}
/*
* 方法,实现文件复制
* 2. 字节流读写字节数组
*/
public static void copy_2(File src,File desc)throws IOException{
FileInputStream fis = new FileInputStream(src);
FileOutputStream fos = new FileOutputStream(desc);
int len = 0 ;
byte[] bytes = new byte[1024];
while((len = fis.read(bytes))!=-1){
fos.write(bytes,0,len);
}
fos.close();
fis.close();
}
/*
* 方法,实现文件复制
* 1. 字节流读写单个字节
*/
public static void copy_1(File src,File desc)throws IOException{
FileInputStream fis = new FileInputStream(src);
FileOutputStream fos = new FileOutputStream(desc);
int len = 0 ;
while((len = fis.read())!=-1){
fos.write(len);
}
fos.close();
fis.close();
}
}
推荐用缓冲流！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！
字符缓冲流
/*
* 使用缓冲区流对象,复制文本文件
* 数据源 BufferedReader+FileReader 读取
* 数据目的 BufferedWriter+FileWriter 写入
* 读取文本行, 读一行,写一行,写换行
*/
public class Copy_1 {
public static void main(String[] args) throws IOException{
BufferedReader bfr = new BufferedReader(new FileReader("c:\\w.log"));
BufferedWriter bfw = new BufferedWriter(new FileWriter("d:\\w.log"));
//读取文本行, 读一行,写一行,写换行
String line = null;
while((line = bfr.readLine())!=null){
bfw.write(line);
bfw.newLine();
bfw.flush();
}
bfw.close();
bfr.close();
}
}
/*
* 打印流实现文本复制
* 读取数据源 BufferedReader+File 读取文本行
* 写入数据目的 PrintWriter+println 自动刷新
*/
public class PrintWriterDemo1 {
public static void main(String[] args) throws IOException{
BufferedReader bfr = new BufferedReader(new FileReader("c:\\a.txt"));
PrintWriter pw = new PrintWriter(new FileWriter("d:\\a.txt"),true);//比BufferedWriter还要省事
String line = null;
while((line = bfr.readLine())!=null){
pw.println(line);
}
pw.close();
bfr.close();
}
}
原文地址：https://blog.csdn.net/Thrive_LCX/article/details/135401905
免责声明：本站文章内容转载自网络资源，如本站内容侵犯了原著者的合法权益，可联系本站删除。更多内容请关注自学内容网（zxcms.com）！