使用java修改图片DPI

修改以后可以直接用PS打开看效果

全部使用rt下的类，无需下载其他jar包

 

import com.sun.image.codec.jpeg.JPEGCodec;  
import com.sun.image.codec.jpeg.JPEGEncodeParam;  
import com.sun.image.codec.jpeg.JPEGImageEncoder;  import javax.imageio.ImageIO;  
import java.awt.image.BufferedImage;  
import java.io.File;  
import java.io.FileOutputStream;  
import java.io.IOException;  public class DPIHandleHelper {  private static int DPI = 300;  public static void main(String[] args) {  String path = "C:\\test.jpg";  File file = new File(path);  handleDpi(file, 300, 300);  }  /** * 改变图片DPI * * @param file * @param xDensity * @param yDensity */  public static void handleDpi(File file, int xDensity, int yDensity) {  try {  BufferedImage image = ImageIO.read(file);  JPEGImageEncoder jpegEncoder = JPEGCodec.createJPEGEncoder(new FileOutputStream(file));  JPEGEncodeParam jpegEncodeParam = jpegEncoder.getDefaultJPEGEncodeParam(image);  jpegEncodeParam.setDensityUnit(JPEGEncodeParam.DENSITY_UNIT_DOTS_INCH);  jpegEncoder.setJPEGEncodeParam(jpegEncodeParam);  jpegEncodeParam.setQuality(0.75f, false);  jpegEncodeParam.setXDensity(xDensity);  jpegEncodeParam.setYDensity(yDensity);  jpegEncoder.encode(image, jpegEncodeParam);  image.flush();  } catch (IOException e) {  e.printStackTrace();  }  }  
}