Java如何设置jpg质量

终于用这段代码做到了…

try{    ImageOutputStream  ios =  ImageIO.createImageOutputStream(var7);    Iterator<ImageWriter> iter = ImageIO.getImageWritersByFormatName("jpeg");    ImageWriter writer = iter.next();    ImageWriteParam iwp = writer.getDefaultWriteParam();    iwp.setCompressionMode(ImageWriteParam.MODE_EXPLICIT);    iwp.setCompressionQuality(0.85f);    writer.setOutput(ios);    writer.write(null, new IIOImage(var6,null,null),iwp);    writer.dispose();    //ImageIO.write(var6, "jpg", var7);}