缩略图工具类

在日常开发中，前端时常会出现这样的场景，图片列表对应一个小缩略图预览，这个其实前端也可以做的，这里放用后台代码生成的

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
package com.vshow.control.tool;

import java.awt.Image;

import java.awt.image.BufferedImage;
import java.io.File;
import java.io.FileOutputStream;

import javax.imageio.ImageIO;

import net.coobird.thumbnailator.Thumbnails;

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

public class ImageUtil {

	
	public static void main(String[] args) throws Exception {
		 File file = new File("D:"+File.separator+"nsh.png");
		 System.out.println(file.getPath());
		 ImageUtil.makeSmallImageT(file,"png","_nsh.png");
	}
    /**
     * 生成缩略图
     * @param srcImageFile 源图片文件的File实例      File file = new File("文件名");
     * @param dstImageFileName 待生成的缩略图片完整路径(生成的格式为：image/jpeg);
     * @throws Exception
     */
    public static void makeSmallImage(File srcImageFile,String dstImageFileName) throws Exception{
        FileOutputStream fileOutputStream = null;
        JPEGImageEncoder encoder = null;
        BufferedImage tagImage = null;
        Image srcImage = null;
        try{
        	
            srcImage = ImageIO.read(srcImageFile);
        	int srcWidth = srcImage.getWidth(null);//原图片宽度
            int srcHeight = srcImage.getHeight(null);//原图片高度
            int dstMaxSize = 120;//目标缩略图的最大宽度/高度，宽度与高度将按比例缩写
            int dstWidth = srcWidth;//缩略图宽度
            int dstHeight = srcHeight;//缩略图高度
            float scale = 0;
            //计算缩略图的宽和高
            if(srcWidth>dstMaxSize){
                dstWidth = dstMaxSize;
                scale = (float)srcWidth/(float)dstMaxSize;
                dstHeight = Math.round((float)srcHeight/scale);
            }
            srcHeight = dstHeight;
            if(srcHeight>dstMaxSize){
                dstHeight = dstMaxSize;
                scale = (float)srcHeight/(float)dstMaxSize;
                dstWidth = Math.round((float)dstWidth/scale);
            }
            //生成缩略图
            tagImage = new BufferedImage(dstWidth,dstHeight,BufferedImage.TYPE_INT_RGB);
            tagImage.getGraphics().drawImage(srcImage,0,0,dstWidth,dstHeight,null);
            fileOutputStream = new FileOutputStream(dstImageFileName);
            encoder = JPEGCodec.createJPEGEncoder(fileOutputStream);
            encoder.encode(tagImage);
            fileOutputStream.close();
            fileOutputStream = null;
        }finally{
            if(fileOutputStream!=null){
                try{
                    fileOutputStream.close();
                }catch(Exception e){
                }
                fileOutputStream = null;
            }
            encoder = null;
            tagImage = null;
            srcImage = null;
            System.gc();
        }
    }
    
    
    /**
     * 生成缩略图2
     * @param srcImageFile 源图片文件的File实例      File file = new File("文件名");
     * @param dstImageFileName 待生成的缩略图片完整路径(生成的格式为：image/jpeg);
     * @throws Exception
     */
    public static void makeSmallImageT(File srcImageFile,String type,String tempname) {

		    try {
		    	
		   	 //Thumbnails.of(srcImageFile)
			 //.size(100, 200)     
			 //.outputFormat(type) //生成图片的格式为png 
			 //.outputQuality(0.5f) //生成质量为80% 	
			 //.toFile(Constant.FILES+File.separator+"_"+tempname);   
		    
		    	 FileHandle.copy3(srcImageFile.getPath(), Constant.FILES + File.separator +"_"+tempname+"."+type);
		    
			} catch (Exception e) {
				
				 FileHandle.copy3(Constant.FILES + File.separator +tempname, Constant.FILES + File.separator +"_"+tempname);
			}
      
    }
    
}