java 按等比压缩图片
package util;
//缩略图实现,将图片(jpg,gif,bmp等等)真实的变成想要的大小
import java.io.*;
import java.util.*;
import com.sun.p_w_picpath.codec.jpeg.*;
import java.awt.p_w_picpath.*;
import java.awt.*;
import java.net.*;
import java.applet.*;
import java.sql.*;
//缩略图类,
//本java类能将jpg图片文件,进行等比或非等比的大小转换。
//具体使用方法
//s_pic(大图片路径,生成小图片路径,大图片文件名,生成小图片文名,生成小图片宽度,生成小图片高度,是否等比缩放(默认为true))
public class DwindlePic{
String InputDir; //输入图路径
String OutputDir; //输出图路径
String InputFileName; //输入图文件名
String OutputFileName; //输出图文件名
int OutputWidth = 80; //默认输出图片宽
int OutputHeight = 80; //默认输出图片高
int rate = 0;
boolean proportion = true; //是否等比缩放标记(默认为等比缩放)
public DwindlePic() {
//初始化变量
InputDir = "";
OutputDir = "";
InputFileName = "";
OutputFileName = "";
OutputWidth = 80;
OutputHeight = 80;
rate = 0;
}
public void setInputDir(String InputDir) {
this.InputDir = InputDir;
}
public void setOutputDir(String OutputDir) {
this.OutputDir = OutputDir;
}
public void setInputFileName(String InputFileName) {
this.InputFileName = InputFileName;
}
public void setOutputFileName(String OutputFileName) {
this.OutputFileName = OutputFileName;
}
public void setOutputWidth(int OutputWidth) {
this.OutputWidth = OutputWidth;
}
public void setOutputHeight(int OutputHeight) {
this.OutputHeight = OutputHeight;
}
public void setW_H(int width, int height) {
this.OutputWidth = width;
this.OutputHeight = height;
}
public String s_pic() {
BufferedImage p_w_picpath;
String NewFileName;
//建立输出文件对象
File file = new File(OutputDir + OutputFileName);
FileOutputStream tempout = null;
try {
tempout = new FileOutputStream(file);
}
catch (Exception ex) {
System.out.println(ex.toString());
}
Image img = null;
Toolkit tk = Toolkit.getDefaultToolkit();
Applet app = new Applet();
MediaTracker mt = new MediaTracker(app);
try {
img = tk.getImage(InputDir + InputFileName);
mt.addImage(img, 0);
mt.waitForID(0);
}
catch (Exception e) {
e.printStackTrace();
}
if (img.getWidth(null) == -1) {
System.out.println(" can't read,retry!" + "<BR>");
return "no";
}
else {
int new_w;
int new_h;
if (this.proportion == true) { //判断是否是等比缩放.
//为等比缩放计算输出的图片宽度及高度
double rate1 = ( (double) img.getWidth(null)) / (double) OutputWidth +
0.1;
double rate2 = ( (double) img.getHeight(null)) / (double) OutputHeight +
0.1;
double rate = rate1 > rate2 ? rate1 : rate2;
new_w = (int) ( ( (double) img.getWidth(null)) / rate);
new_h = (int) ( ( (double) img.getHeight(null)) / rate);
}
else {
new_w = OutputWidth; //输出的图片宽度
new_h = OutputHeight; //输出的图片高度
}
BufferedImage buffImg = new BufferedImage(new_w, new_h,BufferedImage.TYPE_INT_RGB);
Graphics g = buffImg.createGraphics();
g.setColor(Color.white);
g.fillRect(0, 0, new_w, new_h);
g.drawImage(img, 0, 0, new_w, new_h, null);
g.dispose();
JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(tempout);
try {
encoder.encode(buffImg);
tempout.close();
}
catch (IOException ex) {
System.out.println(ex.toString());
}
}
return "ok";
}
public String s_pic(String InputDir, String OutputDir, String InputFileName,
String OutputFileName) {
//输入图路径
this.InputDir = InputDir;
//输出图路径
this.OutputDir = OutputDir;
//输入图文件名
this.InputFileName = InputFileName;
//输出图文件名
this.OutputFileName = OutputFileName;
return s_pic();
}
public String s_pic(String InputDir, String OutputDir, String InputFileName,
String OutputFileName, int
width, int height, boolean gp) {
//输入图路径
this.InputDir = InputDir;
//输出图路径
this.OutputDir = OutputDir;
//输入图文件名
this.InputFileName = InputFileName;
//输出图文件名
this.OutputFileName = OutputFileName;
//设置图片长宽
setW_H(width, height);
//是否是等比缩放 标记
this.proportion = gp;
return s_pic();
}
// 测试类
public static void main(String[] a)
{
//s_pic(大图片路径,生成小图片路径,大图片文件名,生成小图片文名,生成小图片宽度,生成小图片高度)
DwindlePic mypic = new DwindlePic();
System.out.println(
mypic.s_pic("e:\\workspace\\baby\\web\\uploadFile\\products\\2007\\11\\02\\",
"e:\\workspace\\baby\\web\\uploadFile\\products\\2007\\11\\02\\",
"20071102194928960.jpg", "new.jpg", 120, 80, true)
);
}
}