Java操作图片改变大小加水印

   在实际的项目开发中，有可能遇到对图片的操作，比如加水印，或是设置图片的大小，先转载一篇文章，以记录相关的操作:

import java.awt.*;
import java.awt.image.*;
import javax.imageio.ImageIO;
import javax.imageio.ImageIO.*;
import javax.imageio.IIOException;
import java.io.*;
import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;
import javax.servlet.http.HttpSession;


// 图片操作，改变大小加水印***********@与羊共舞的狼
public class ImageOperate {


/**
* 给图片加水印，但不改变大小
* @param strOriginalFileName String(原始文件)
* @param strWaterMarkFileName String(水印后)
*/
public void waterMark(String strOriginalFileName,String strWaterMarkFileName,HttpSession session){
try{
//源文件
String root=session.getServletContext().getRealPath("/");
File fileOriginal = new File(root+strOriginalFileName);
Image imageOriginal = ImageIO.read(fileOriginal);
int widthOriginal = imageOriginal.getWidth(null);
int heightOriginal = imageOriginal.getHeight(null);
System.out.println("widthOriginal:" + widthOriginal + "theightOriginal:" + heightOriginal);

BufferedImage bufImage = new BufferedImage(widthOriginal,heightOriginal,BufferedImage.TYPE_INT_RGB);
Graphics g = bufImage.createGraphics();
g.drawImage(imageOriginal,0,0,widthOriginal,heightOriginal,null);

//水印文件
File fileWaterMark = new File(root+strWaterMarkFileName);
Image imageWaterMark = ImageIO.read(fileWaterMark);
int widthWaterMark = imageWaterMark.getWidth(null);
int heightWaterMark = imageWaterMark.getHeight(null);
System.out.println("widthWaterMark:" + widthWaterMark + "theightWaterMark:" + heightWaterMark);

//水印文件在源文件的右下角
g.drawImage(imageWaterMark,widthOriginal - widthWaterMark,heightOriginal - heightWaterMark,widthWaterMark,heightWaterMark,null);
g.dispose();

FileOutputStream fos = new FileOutputStream( root+strOriginalFileName);
JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(fos);
encoder.encode(bufImage);
fos.flush();
fos.close();
fos = null;
}
catch(Exception e)
{
e.printStackTrace();
}
}
/**
* 修改图片大小
*/
public void alterSize(String srcImgFile,String addChar,int new_w,int new_h,HttpSession session){

//System.out.print("文件路径为:"+"//"+srcImgFile);

String root=session.getServletContext().getRealPath("/");
java.io.File file=new java.io.File(root+srcImgFile);
if(file.exists())
System.out.println("文件存在");
else
System.out.println("文件不存在");

int i = srcImgFile.indexOf(".");
int sLen = srcImgFile.length();
String suffix = srcImgFile.substring(i, sLen); //带点+后缀名
String urlName=srcImgFile.substring(0,i); //路径+文件名
String newUrlName=root+urlName+addChar+suffix;
//System.out.print("新文件名为"+newUrlName);
Image src=null;
try
{
src = javax.imageio.ImageIO.read(file);
java.awt.image.BufferedImage tag = new java.awt.image.BufferedImage(new_w,new_h,java.awt.image.BufferedImage.TYPE_INT_RGB);
tag.getGraphics().drawImage(src,0,0,new_w,new_h,null);
FileOutputStream newimage=new FileOutputStream(newUrlName);
JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(newimage);
encoder.encode(tag); //近JPEG编码
newimage.close();

}
catch(IIOException ee)
{
ee.printStackTrace();
System.out.print("这里出错了");
}
catch(Exception e)
{
e.printStackTrace();
}
}//End sizeAlter


}

如果对网络文件进行设置格式大小的话，代码如下：

java.io.File file = new java.io.File(srcImgFile);
		if (file.exists())
			System.out.println("文件存在");
		else
			System.out.println("文件不存在");

		int i = srcImgFile.lastIndexOf(".");
		int sLen = srcImgFile.length();
		String suffix = srcImgFile.substring(i, sLen); // 带点+后缀名
		String urlName = srcImgFile.substring(0, i); // 路径+文件名
		String newUrlName = "D:/" + addChar + suffix;
		// System.out.print("新文件名为"+newUrlName);
		Image src = null;
		/**
		 * 网络文件抓取同时设置其宽高
		 */
		try {
			URL url = new URL(srcImgFile);
			HttpURLConnection urlcon = (HttpURLConnection) url.openConnection();
			urlcon.connect();
			src = javax.imageio.ImageIO.read(urlcon.getInputStream());
			java.awt.image.BufferedImage tag = new java.awt.image.BufferedImage(
					new_w, new_h, java.awt.image.BufferedImage.TYPE_INT_RGB);
			tag.getGraphics().drawImage(src, 0, 0, new_w, new_h, null);
			FileOutputStream newimage = new FileOutputStream(newUrlName);
			JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(newimage);
			encoder.encode(tag); //近JPEG编码
			newimage.close();

		} catch (IIOException ee) {
			ee.printStackTrace();
			System.out.print("这里出错了");
		} catch (Exception e) {
			e.printStackTrace();
		}