[转载]java图片缩放处理

原文地址：java图片缩放处理作者：jack

package com.bluecms.common.util;

import java.awt.Image;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;

import javax.imageio.ImageIO;

import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;

public class ImageZoomUtils {
 private File file = null; // 文件对象   
    private String inputDir; // 输入图路径 此处若是文件上传的话把文件的输入路径也设置成服务器端的路径（就是在文件上传完成后做处理）这样会便于你去做图片的处理，因为本段代码并不支持url的解析
    private String outputDir; // 输出图路径也可以在这个里面加上一段url的解析处理，这样你的输出路径就会即支持url，也支持本地的缩放 
    private String inputFileName; // 输入图文件名  
    private String outputFileName; // 输出图文件名  
    private int outputWidth = 100; // 默认输出图片宽  
    private int outputHeight = 100; // 默认输出图片高  
    private boolean proportion = true; // 是否等比缩放标记(默认为等比缩放)  
    private InputStream in;
    public ImageZoomUtils()
    { // 初始化变量  
        inputDir = "";   
        outputDir = "";   
        inputFileName = "";   
        outputFileName = "";   
        outputWidth = 100;   
        outputHeight = 100; 
        in=null;
    }   
    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 setWidthAndHeight(int width, int height) {   
        this.outputWidth = width;  
        this.outputHeight = height;   
    }   
    public InputStream getIn() {
  return in;
 }
 public void setIn(InputStream in) {
  this.in = in;
 }
    
    public long getPicSize(String path) {   
        file = new File(path);   
        return file.length();   
    }  
      
    // 图片处理   
    public String zoomPicture() {   
        try {   
            //获得源文件   
            file = new File(inputDir + inputFileName);   
            if (!file.exists()) {   
                return "";   
            }
           
            Image img = ImageIO.read(in);   //如果是本地图片处理的话，这个地方直接把file放到ImageIO.read(file)中即可，如果是执行上传图片的话，  Formfile formfile=获得表单提交的Formfile ,然后 ImageIO.read 方法里参数放 formfile.getInputStream()
            // 判断图片格式是否正确   
            if (img.getWidth(null) == -1) {  
                 
                return "no";
            } else {   
                int newWidth; int newHeight;   
                // 判断是否是等比缩放   
                if (this.proportion == true) {   
                    // 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;   
                    // 根据缩放比率大的进行缩放控制   
                    double rate = rate1 > rate2 ? rate1 : rate2;   
                    newWidth = (int) (((double) img.getWidth(null)) / rate);   
                    newHeight = (int) (((double) img.getHeight(null)) / rate);   
                } else {   
                    newWidth = outputWidth; // 输出的图片宽度   
                    newHeight = outputHeight; // 输出的图片高度   
                }   
               BufferedImage tag = new BufferedImage((int) newWidth, (int) newHeight, BufferedImage.TYPE_INT_RGB);   
                 
                  
               tag.getGraphics().drawImage(img.getScaledInstance(newWidth, newHeight, Image.SCALE_SMOOTH), 0, 0, null);  
               FileOutputStream out = new FileOutputStream(outputDir + outputFileName);  
               // JPEGImageEncoder可适用于其他图片类型的转换   
               JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);
               encoder.encode(tag);   
               out.close();   
            }   
        } catch (IOException ex) {   
            ex.printStackTrace();   
        }   
        return "ok";   
   } 
   public String zoomPicture(String inputDir, String outputDir, String inputFileName, String outputFileName, int width, int height, boolean gp,InputStream in) {   
       // 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;
       this.in=in;
       // 设置图片长宽  
       setWidthAndHeight(width, height);   
       // 是否是等比缩放标记   
       this.proportion = gp;   
       return compressPic();   
   }   
  
 

}