java圖片壓縮

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Java代碼： 
/** 
*  縮略圖實現，將圖片(jpg、bmp、png、gif等等)真實的變成想要的大小 
*/ 
package com.joewalker.test; 

import java.awt.Image; 
import java.awt.p_w_picpath.BufferedImage; 
import java.io.File; 
import java.io.FileOutputStream; 
import java.io.IOException; 
import javax.p_w_picpathio.ImageIO; 
import com.sun.p_w_picpath.codec.jpeg.JPEGCodec; 
import com.sun.p_w_picpath.codec.jpeg.JPEGImageEncoder; 

/******************************************************************************* 
* 縮略圖類（通用） 本java類能將jpg、bmp、png、gif圖片文件，進行等比或非等比的大小轉換。 具體使用方法 
* compressPic(大圖片路徑,生成小圖片路徑,大圖片文件名,生成小圖片文名,生成小圖片寬度,生成小圖片高度,是否等比縮放(默認爲true)) 
*/ 
public class CompressPicDemo { 
         private File file = null; // 文件對象 
         private String inputDir; // 輸入圖路徑 
         private String outputDir; // 輸出圖路徑 
         private String inputFileName; // 輸入圖文件名 
         private String outputFileName; // 輸出圖文件名 
         private int outputWidth = 100; // 默認輸出圖片寬 
         private int outputHeight = 100; // 默認輸出圖片高 
         private boolean proportion = true; // 是否等比縮放標記(默認爲等比縮放) 
         public CompressPicDemo() { // 初始化變量 
                 inputDir = ""; 
                 outputDir = ""; 
                 inputFileName = ""; 
                 outputFileName = ""; 
                 outputWidth = 100; 
                 outputHeight = 100; 
         } 
         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; 
         } 
         
         /* 
          * 獲得圖片大小 
          * 傳入參數 String path ：圖片路徑 
          */ 
         public long getPicSize(String path) { 
                 file = new File(path); 
                 return file.length(); 
         } 
         
         // 圖片處理 
         public String compressPic() { 
                 try { 
                         //獲得源文件 
                         file = new File(inputDir + inputFileName); 
                         if (!file.exists()) { 
                                 return ""; 
                         } 
                         Image img = ImageIO.read(file); 
                         // 判斷圖片格式是否正確 
                         if (img.getWidth(null) == -1) { 
                                 System.out.println(" can't read,retry!" + "<BR>"); 
                                 return "no"; 
                         } else { 
                                 int newWidth; int newHeight; 
                                 // 判斷是否是等比縮放 
                                 if (this.proportion == true) { 
                                         // 爲等比縮放計算輸出的圖片寬度及高度 
                                         double rate1 = ((double) img.getWidth(null)) / (double) outputWidth + 0.1; 
                                         double rate2 = ((double) img.getHeight(null)) / (double) outputHeight + 0.1; 
                                         // 根據縮放比率大的進行縮放控制 
                                         double rate = rate1 > rate2 ? rate1 : rate2; 
                                         newWidth = (int) (((double) img.getWidth(null)) / rate); 
                                         newHeight = (int) (((double) img.getHeight(null)) / rate); 
                                 } else { 
                                         newWidth = outputWidth; // 輸出的圖片寬度 
                                         newHeight = outputHeight; // 輸出的圖片高度 
                                 } 
                                 BufferedImage tag = new BufferedImage((int) newWidth, (int) newHeight, BufferedImage.TYPE_INT_RGB); 
                                 
                                 /* 
                                 * Image.SCALE_SMOOTH 的縮略算法 生成縮略圖片的平滑度的 
                                 * 優先級比速度高 生成的圖片質量比較好 但速度慢 
                                 */ 
                                 tag.getGraphics().drawImage(img.getScaledInstance(newWidth, newHeight, Image.SCALE_SMOOTH), 0, 0, null); 
                                 FileOutputStream out = new FileOutputStream(outputDir + outputFileName); 
                                 // JPEGImageEncoder可適用於其他圖片類型的轉換 
                                 JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out); 
                                 encoder.encode(tag); 
                                 out.close(); 
                         } 
                 } catch (IOException ex) { 
                         ex.printStackTrace(); 
                 } 
                 return "ok"; 
        } 
        public String compressPic (String inputDir, String outputDir, String inputFileName, String outputFileName) { 
                // 輸入圖路徑 
                this.inputDir = inputDir; 
                // 輸出圖路徑 
                this.outputDir = outputDir; 
                // 輸入圖文件名 
                this.inputFileName = inputFileName; 
                // 輸出圖文件名 
                this.outputFileName = outputFileName; 
                return compressPic(); 
        } 
        public String compressPic(String inputDir, String outputDir, String inputFileName, String outputFileName, int width, int height, boolean gp) { 
                // 輸入圖路徑 
                this.inputDir = inputDir; 
                // 輸出圖路徑 
                this.outputDir = outputDir; 
                // 輸入圖文件名 
                this.inputFileName = inputFileName; 
                // 輸出圖文件名 
                this.outputFileName = outputFileName; 
                // 設置圖片長寬 
                setWidthAndHeight(width, height); 
                // 是否是等比縮放 標記 
                this.proportion = gp; 
                return compressPic(); 
        } 
        
        // main測試 
        // compressPic(大圖片路徑,生成小圖片路徑,大圖片文件名,生成小圖片文名,生成小圖片寬度,生成小圖片高度,是否等比縮放(默認爲true)) 
        public static void main(String[] arg) { 
                CompressPicDemo mypic = new CompressPicDemo(); 
                System.out.println("輸入的圖片大小：" + mypic.getPicSize("e:\\1.jpg")/1024 + "KB"); 
                int count = 0; // 記錄全部圖片壓縮所用時間 
                for (int i = 0; i < 100; i++) { 
                        int start = (int) System.currentTimeMillis();        // 開始時間 
                        mypic.compressPic("e:\\", "e:\\test\\", "1.jpg", "r1"+i+".jpg", 120, 120, true); 
                        int end = (int) System.currentTimeMillis(); // 結束時間 
                        int re = end-start; // 但圖片生成處理時間 
                        count += re; System.out.println("第" + (i+1) + "張圖片壓縮處理使用了: " + re + "毫秒"); 
                        System.out.println("輸出的圖片大小：" + mypic.getPicSize("e:\\test\\r1"+i+".jpg")/1024 + "KB"); 
                } 
                System.out.println("總共用了：" + count + "毫秒"); 
        }