图片复制

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;

/**

• 拷贝图片

• @author WangShuang

• */
  public class Demo {

  public static void main(String[] args) {
  copy_3();
  }
  /**

  • 效率不如copy_2高
    */
    public static void copy_1(){
    FileInputStream in = null;
    FileOutputStream out = null;
    try {
    in = new FileInputStream("c:\timg.jpg");
    out = new FileOutputStream("D:\timg.jpg");
    int ch = 0;
    while((ch=in.read())!=-1){
    out.write(ch);
    }

    } catch (IOException e) {
    e.printStackTrace();
    }finally {

    try {    if(out!=null){        out.close();    }} catch (IOException e) {    e.printStackTrace();}try {    if(in!=null){        in.close();    }} catch (Exception e2) {    e2.printStackTrace();}

    }
    }
    //最通用的方法
    public static void copy_2(){
    FileInputStream in = null;
    FileOutputStream out = null;
    try {
    in=new FileInputStream("c:\timg.jpg");
    out=new FileOutputStream("d:\timg.jpg");
    byte[] buffer = new byte[1024];
    int len = 0;
    while((len=in.read(buffer))!=-1){
    out.write(buffer, 0, len);
    }

    } catch (Exception e) {
    e.printStackTrace();
    }finally {
    try {
    if(out!=null){
    out.close();
    }
    } catch (IOException e) {
    e.printStackTrace();
    }
    try {
    if(in!=null){
    in.close();
    }
    } catch (Exception e2) {
    e2.printStackTrace();
    }
    }
    }
    //适合文件比较小的情况
    public static void copy_3(){
    FileInputStream in = null;
    FileOutputStream out = null;
    try {
    in=new FileInputStream("c:\timg.jpg");
    out=new FileOutputStream("d:\timg.jpg");
    int available = in.available();//返回文件大小
    byte buffer[] = new byte[available];
    in.read(buffer);
    out.write(buffer);
    } catch (Exception e) {
    e.printStackTrace();
    }finally {
    try {
    if(out!=null){
    out.close();
    }
    } catch (IOException e) {
    e.printStackTrace();
    }
    try {
    if(in!=null){
    in.close();
    }
    } catch (Exception e2) {
    e2.printStackTrace();
    }
    }
    }
    }