图片上传压缩

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web开发中将上传图片压缩后以image类型存入数据库（转）
2009-03-11 17:45

转自http://blog.sina.com.cn/s/blog_4ce383f30100chmm.html

不久前，本人在一个小型java web项目开发中需要上传一个图片的同时，将其进行适当压缩，然后直接以image类型存入SQL Server数据库。之前，本人在网络上查找了好长时间，都没有找到合适的源码，要么就是存原图片，要么就是把图片压缩后存到服务器上，然后把相对路径以string类型存入数据库或以image类型存入数据库，本例与其不同的是，要求图片在内存中压缩后直接以image类型存入数据库。具体实现如下：

①首先，新建一个upload.jsp文件,用来选择需要上传的图片，源码如下:

<%@ page contentType="text/html; charset=gb2312" language="java"
import="java.sql.*" errorPage=""%>



















上传并压缩图片应用





请选择上传的图片















②然后，创建一个servlet文件ImgDealServlet.java，用来处理图片的上传，源码如下：

package servlet;

import java.awt.Color;
import java.awt.Graphics;
import java.awt.Image;

import java.awt.image.BufferedImage;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.sql.ResultSet;


import util.*;

import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.jspsmart.upload.SmartUpload;

public class ImgDealServlet extends HttpServlet {

public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {


request.setCharacterEncoding("GB2312");
response.setContentType("text/html; charset=GB2312");

PrintWriter out = response.getWriter();

SmartUpload mySmartUpload = new SmartUpload();
mySmartUpload.initialize(getServletConfig(),request,response);


try {
mySmartUpload.setAllowedFilesList("jpg,JPG,gif");
//上载文件
mySmartUpload.upload();
} catch (Exception e) {
out.print("");
}
try {
com.jspsmart.upload.File myFile = mySmartUpload.getFiles().getFile(0);
// 若文件不存在
if (myFile.isMissing()) {
out.print("");
}
else {

String myFilePath=myFile.getFilePathName(); //取得上载的文件的路径
UploadImg ui=new UploadImg();
BufferedImage tag =ui.getResizeImg(myFilePath,400,300,true);
if(tag!=null){
ui.saveImgToDB(tag);
}
response.sendRedirect("showimg.jsp");

}
} catch (Exception e) {
e.toString();
}
}


public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {

doGet(request,response);
}

}

③之前的servlet文件中用到了一个自定义包中的类UploadImg.java，其中定义了图片处理的方法，其源码如下：

package util;

import java.awt.Graphics;
import java.awt.Image;
import java.awt.image.BufferedImage;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import javax.imageio.ImageIO;
import util.DBConnect;

public class UploadImg {
String myFilePath = "";

public BufferedImage getResizeImg(String path, int width, int height,
boolean isResize) {

String myFilePath = path; // 取得上载的文件的路径
BufferedImage srcimg, tag;
tag = null;
int new_w; // 压缩后大小
int new_h;
boolean Resize;// 是否等比缩放

try {
srcimg = ImageIO.read(new java.io.File(myFilePath));
if (isResize) {// 等比缩放
double rate1 = ((double) srcimg.getWidth(null))
/ (double) width + 0.1;
double rate2 = ((double) srcimg.getHeight(null))
/ (double) height + 0.1;
double rate = rate1 > rate2 ? rate1 : rate2;
new_w = (int) (((double) srcimg.getWidth(null)) / rate);
new_h = (int) (((double) srcimg.getHeight(null)) / rate);
} else {
new_w = width;
new_h = height;
}
Image image = srcimg.getScaledInstance(new_w, new_h,
Image.SCALE_DEFAULT);
tag = new BufferedImage(new_w, new_h, BufferedImage.TYPE_INT_RGB);
Graphics g = tag.getGraphics();
g.drawImage(image, 0, 0, null); // 绘制缩小后的图
g.dispose();
return tag;

} catch (Exception e) {
e.printStackTrace();
}
return tag;
}

public void saveImgToDB(BufferedImage bi) {
ByteArrayOutputStream baos = new ByteArrayOutputStream();
BufferedImage tag = bi;
try {
ImageIO.write(tag, "jpg", baos);
byte[] bytes = baos.toByteArray();
ByteArrayInputStream bis = new ByteArrayInputStream(bytes);
String strsql = "update imgtest set img=? where id=1";
DBConnect dbcSelect = new DBConnect(strsql);
dbcSelect.setBinaryStream(1, bis, bytes.length);
dbcSelect.executeUpdate();
dbcSelect.close();
} catch (Exception e) {
}
}

}

④上面的Upload.java文件中同样也用到了另一个自定义的数据库连接类DBConnect.java,源码如下：

package util;

import java.io.InputStream;
import java.sql.*;

public class DBConnect {
private Connection conn = null;

private Statement stmt = null;

private PreparedStatement prepstmt = null;

public static final int JADMIS_CONNECT = 3;

public static final int FTFORDE_CONNECT = 2;

public static final int WEBSITE_CONNECT = 1;

public static final int PLATFORM_CONNECT = 0;

void init() {
try {
Class.forName("org.logicalcobwebs.proxool.ProxoolDriver");
conn = DriverManager.getConnection("proxool.mysql");
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}


void init(String conName) {
try {
Class.forName("org.logicalcobwebs.proxool.ProxoolDriver");
conn = DriverManager.getConnection("proxool." + conName);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}

public DBConnect(int ConnectIndex) throws SQLException {
switch (ConnectIndex) {
case JADMIS_CONNECT:
init("jadmis");
break;
case WEBSITE_CONNECT:
init("website");
break;
case PLATFORM_CONNECT:
init("mysql");
break;
case FTFORDE_CONNECT:
init("ftde");
break;
}
stmt = conn.createStatement();
}

public DBConnect(int ConnectIndex, int resultSetType,
int resultSetConcurrency) throws SQLException {
switch (ConnectIndex) {
case JADMIS_CONNECT:
init("jadmis");
break;
case WEBSITE_CONNECT:
init("website");
break;
case PLATFORM_CONNECT:
init("mysql");
break;
case FTFORDE_CONNECT:
init("ftde");
break;
}
stmt = conn.createStatement(resultSetType, resultSetConcurrency);
}


public DBConnect() throws SQLException {
init();
stmt = conn.createStatement();
}

public DBConnect(int resultSetType, int resultSetConcurrency)
throws SQLException {
init();
stmt = conn.createStatement(resultSetType, resultSetConcurrency);
}


public DBConnect(String sql) throws SQLException {
init();
this.prepareStatement(sql);
}

public DBConnect(String sql, int resultSetType, int resultSetConcurrency)
throws SQLException {
init();
this.prepareStatement(sql, resultSetType, resultSetConcurrency);
}
//added by tmw 080221
public DBConnect(int ConnectIndex,String sql) throws SQLException {
switch (ConnectIndex) {
case WEBSITE_CONNECT:
init("website");
break;
case PLATFORM_CONNECT:
init("ft");
break;
case FTFORDE_CONNECT:
init("ftde");
break;
case JADMIS_CONNECT:
init("mysql");
break;
}
this.prepareStatement(sql);
}
//added by tmw 080221
public DBConnect(int ConnectIndex,String sql, int resultSetType, int resultSetConcurrency)
throws SQLException {
switch (ConnectIndex) {
case WEBSITE_CONNECT:
init("website");
break;
case PLATFORM_CONNECT:
init("ft");
break;
case FTFORDE_CONNECT:
init("ftde");
break;
case JADMIS_CONNECT:
init("mysql");
break;
}
this.prepareStatement(sql, resultSetType, resultSetConcurrency);
}

public Connection getConnection() {
return conn;
}


public void prepareStatement(String sql) throws SQLException {
prepstmt = conn.prepareStatement(sql);
}

public void prepareStatement(String sql, int resultSetType,
int resultSetConcurrency) throws SQLException {
prepstmt = conn.prepareStatement(sql, resultSetType,
resultSetConcurrency);
}


public void setString(int index, String value) throws SQLException {
prepstmt.setString(index, value);
}

public void setInt(int index, int value) throws SQLException {
prepstmt.setInt(index, value);
}

public void setBoolean(int index, boolean value) throws SQLException {
prepstmt.setBoolean(index, value);
}

public void setDate(int index, Date value) throws SQLException {
prepstmt.setDate(index, value);
}

public void setLong(int index, long value) throws SQLException {
prepstmt.setLong(index, value);
}
//add by sch
public void setDouble(int index, double value) throws SQLException {
prepstmt.setDouble(index, value);
}
//add by sch
public void setObject(int index, Object value)throws SQLException {
prepstmt.setObject(index,value);
}
public void setFloat(int index, float value) throws SQLException {
prepstmt.setFloat(index, value);
}

public void setBytes(int index, byte[] value) throws SQLException {
prepstmt.setBytes(index, value);
}

public void setBinaryStream(int index, InputStream is, int length)
throws SQLException {
prepstmt.setBinaryStream(index, is, length);
}

public void clearParameters() throws SQLException {
prepstmt.clearParameters();
prepstmt = null;
}


public PreparedStatement getPreparedStatement() {
return prepstmt;
}


public Statement getStatement() {
return stmt;
}


public ResultSet executeQuery(String sql) throws SQLException {
if (stmt != null) {
return stmt.executeQuery(sql);
} else
return null;
}

public ResultSet executeQuery() throws SQLException {
if (prepstmt != null) {
return prepstmt.executeQuery();
} else
return null;
}


public void executeUpdate(String sql) throws SQLException {
if (stmt != null)
stmt.executeUpdate(sql);
}

public void executeUpdate() throws SQLException {
if (prepstmt != null)
prepstmt.executeUpdate();
}


public void close() throws SQLException {
if (stmt != null) {
stmt.close();
stmt = null;
}
if (prepstmt != null) {
prepstmt.close();
prepstmt = null;
}
if (conn != null) {

conn.close();
conn=null;

}
}
}

⑤此外，由于用到了proxool数据库连接池，所以需要添加proxool.xml并修改web.xml配置文件，proxool.xml源码如下：





mysql
jdbc:jtds:sqlserver://localhost:1433;DatabaseName=lwjtest
net.sourceforge.jtds.jdbc.Driver






ServletConfigurator
org.logicalcobwebs.proxool.configuration.ServletConfigurator

xmlFile
WEB-INF/proxool.xml

1


Admin
org.logicalcobwebs.proxool.admin.servlet.AdminServlet


Admin
/admin





ImgDealServlet
servlet.ImgDealServlet



ImgDealServlet
/ImgDealServlet


upfile.jsp



⑥此外，还需要导入几个jar包，jspsmartupload.jar、jtds-1.1.jar和proxool-0.9.0RC3.jar，至于这三个包是做什么用的，我想就不用我多说了吧。

两个图片我用的都是BufferedImage类，因为不同了解流的用法，所以可能会有些不当。此外，还有一点要说明的是，如果jsp文件中字符编码格式用utf-8时，不支持图片的中文路径，改为gb2312就OK了。

由于是第一次发帖，且源码基本为本人及朋友所改写，错误及不当之处一定不少，还请大家多多指教，在此谢过！