jsp中图片处理相关操作

2022-07-15 80酷酷网 80kuku.com

<% page contentType="text/html;charset=gb2312"%>
<% page import="java.sql.*,java.io.*,java.awt.Image,java.awt.image.*,com.sun.image.codec.jpeg.*"%>
<html>
<body>
<%
/*
drop table imagetable;
create table imagetable
(
   nid                            int                            not null,
   image                          blob,
   primary key (nid)
)
type = InnoDB;

/*
//＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝一、将文件写入到数据库的大字段中begin＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝
Class.forName("org.gjt.mm.mysql.Driver").newInstance();
String url ="jdbc:mysql://localhost:3306/test?user=root&password=eastsoftweb";
Connection conn= DriverManager.getConnection(url);
java.io.File file = new File("d:/temp/1.jpg");
FileInputStream is=new FileInputStream(file);
PreparedStatement stmt = conn.prepareStatement(
"INSERT INTO imagetable (nid,image)" +
"VALUES (?, ?)"); //预编译SQL语句
stmt.setInt(1, 1);
stmt.setBinaryStream(2, is,(int)file.length());
stmt.executeUpdate();
stmt.close();
is.close();
out.println("update end");
//＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝将文件写入到数据库的大字段中end＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝
*/

/*
//＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝二、jsp显示服务器硬盘图片示例 begin＝＝＝＝＝＝＝＝＝＝＝＝＝＝

FileInputStream is=new FileInputStream("d:/temp/1.JPG");
response.reset();
response.setContentType("image/jpeg");
ServletOutputStream sos = response.getOutputStream();
byte[] buffer = new byte[1024];
int len=0;
while((len=is.read(buffer))>0){
sos.write(buffer,0,len);
}
sos.flush();
sos.close();

//＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝jsp显示服务器硬盘图片示例 end＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝
*/

//＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝三、将数据库的大字段图片还原到本地,并在网页上显示begin＝＝＝＝＝＝＝＝＝＝＝＝＝＝
Class.forName("org.gjt.mm.mysql.Driver").newInstance();
String url ="jdbc:mysql://localhost:3306/test?user=root&password=eastsoftweb";
Connection conn= DriverManager.getConnection(url);
java.io.File file = new File("d:/temp/db.jpg");
FileOutputStream os=new FileOutputStream(file);
Statement stmt=conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_READ_ONLY);
ResultSet rs=stmt.executeQuery("select nid,image from imagetable where nid=1");
rs.next();
byte[] buffer=rs.getBytes(2);
stmt.close();
os.write(buffer);
os.flush();
os.close();
out.println("query end");

//网页上显示
response.reset();
response.setContentType("image/jpeg");
ServletOutputStream sos = response.getOutputStream();
sos.write(buffer);
sos.flush();
sos.close();
//＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝将数据库的大字段图片还原到本地,并在网页上显示end＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝

/*
//＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝四、生成缩略图begin＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝
File file = new File("d:/temp/1.JPG");
String newurl="d:/temp/2.jpg"; //新的缩略图保存地址
Image src = javax.imageio.ImageIO.read(file);                     //构造Image对象
float tagsize=200;
int old_w=src.getWidth(null);                                     //得到源图宽
int old_h=src.getHeight(null);
int new_w=0;
int new_h=0;                            //得到源图长
int tempsize;
float tempdouble;
if(old_w>old_h){
tempdouble=old_w/tagsize;
}else{
tempdouble=old_h/tagsize;
}
new_w=Math.round(old_w/tempdouble);
new_h=Math.round(old_h/tempdouble);//计算新图长宽
BufferedImage tag = new BufferedImage(new_w,new_h,BufferedImage.TYPE_INT_RGB);
tag.getGraphics().drawImage(src,0,0,new_w,new_h,null);       //绘制缩小后的图
FileOutputStream newimage=new FileOutputStream(newurl);          //输出到文件流
JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(newimage);
encoder.encode(tag);                                               //近JPEG编码
newimage.close();
//＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝生成缩略图end＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝
*/
%>