SQLSERVER2005读取图片类型字段
下午向数据库SQL SERVER中遇到添加图片类型数据的问题，本以为在界面管理器中可以直接（通过指定路径把图片的数据保存起来）添加图片却不然。网上搜了下找到了相关的较专业的资料，整合解读一下：
两种方法：
第一就是在数据库中存储图片的路径，然后在程序中根据读取的路径读取图片；这种方法简单、容易使用，但是在图片过多时不好管理。
第二种就是将图片转换成二进制存储于数据库中，sql server 2005有个image数据类型,专门用于存储图片，Image数据类型存储的是长度不确定的二进制数据，最大长度是2GB。
第二种方法（详情请参阅：详述的过程）
简述过程：
当然首先得有存储图片字段的数据库、表。
如何插入图片：
大致流程：其他图片格式--》image类型的转化--》到MemoryStream流的转换--》到二进制的转换--》插入到数据库。
如何得到图片：
大致流程：选取数据库中的image类型字段--》转化为二进制流--》转化为MemoryStream流--》转化为Image图片格式类型。
其它：如何插入读取一个文件、如何保存数据库中的image字段到一个文件。。
Connection conn ;
conn= ConnectionFactory.getConn();
PreparedStatement ps;
//建立Statement对象
String name=request.getParameter("picname");
String img=request.getParameter("pic");
//获得所要显示图片的标题、存储路径、内容，并进行中文编码
FileInputStream str=new FileInputStream(img);
//String sql="insert into p(picname,pic) values(?,?)";
String sql="INSERT INTO test_Img(name,img) VALUES(?,?)";
ps=conn.prepareStatement(sql);
ps.setString(1,name);
ps.setBinaryStream(2,str,str.available());
ps.execute();
//将数据存入数据库
out.println("Success,You Have Insert an Image Successfully");
/**
* Created by IntelliJ IDEA.
* User: ljt
* Date: 2003-3-31
* Time: 18:51:38
* To change this template use Options | File Templates.
*/
import oracle.jdbc.driver.OraclePreparedStatement;
import oracle.jdbc.driver.OracleResultSet;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.Statement;
import java.sql.Clob;
public class TestOpenDoc {
public OracleResultSet ors = null; //**这里rs一定要用Oracle提供的
public OraclePreparedStatement opst = null; //**PreparedStatement用
public Connection conn = null;
public Statement stmt = null;
public TestOpenDoc() {
}
public boolean getConnect() {
//这是我的数据库所在
String serverName = "prosrv";
try {
Class.forName("oracle.jdbc.driver.OracleDriver");
String url = "jdbc:oracle:thin:@" + serverName + ":1521:BOHDATA";
conn = DriverManager.getConnection(url, "appuser", "appuser");
}
catch (Exception e) {
System.out.println(e);
return false;
}
return true;
}
public static void main(String[] args) {
TestOpenDoc test = new TestOpenDoc();
if (!test.getConnect()) {
System.out.println("数据库连结错误");
return ;
}
try{
test.conn.setAutoCommit(false);
byte a[] = null; //**将测试文件test.doc读入此字节数组
java.io.FileInputStream fin = null;
java.io.FileOutputStream fout = null;
//Oracle提供的
try {
java.io.File f1 = new java.io.File("c:/test.doc");
java.io.File f2 = new java.io.File("d:/testout.doc"); //**从BLOB读出的信息写
//入该文 件，和源文件对比测试用
fin = new java.io.FileInputStream(f1);
fout = new java.io.FileOutputStream(f2);
int flength = (int) f1.length(); //**读入文件的字节长度
System.out.println("file length::" + flength);
a = new byte[flength];
int i = 0;
int itotal = 0;
//* 将文件读入字节数组
for (; itotal < flength; itotal = i + itotal) {
i = fin.read(a, itotal, flength - itotal);
}
fin.close();
System.out.println("read itotal::" + itotal);
//**注意Oracle的 BLOB一定要用EMPTY_BLOB()初始化
String mysql =
"insert into filelist (FileName,FileSize,FileBody) values (?,?,EMPTY_BLOB())";
OraclePreparedStatement opst = (OraclePreparedStatement) test.conn.
prepareStatement(mysql);
opst.setString(1, "wordtemplate2");
opst.setInt(2, flength);
opst.executeUpdate();
opst.clearParameters();
// /**插入其它数据后，定位BLOB字段
mysql = "select filebody from filelist where filename=?";
opst = (OraclePreparedStatement) test.conn.prepareStatement(mysql);
opst.setString(1, "wordtemplate2");
OracleResultSet ors = (OracleResultSet) opst.executeQuery();
if (ors.next()) {
oracle.sql.BLOB blob = ors.getBLOB(1); //**得到BLOB字段
int j = blob.putBytes(1, a); //**将字节数组写入BLOB字段
System.out.println("j:" + j);
test.conn.commit();
ors.close();
Clob clob;
clob = ors.getClob("");
String str;
str = clob.toString();
str = clob.getSubString(0L,(int)clob.length());
System.out.println(str);
}
System.out.println("insert into ok");
byte b[] = null; //**保存从BLOB读出的字节
opst.clearParameters();
mysql = "select filebody from filelist where filename=?";
opst = (OraclePreparedStatement) test.conn.
prepareStatement(mysql);
opst.setString(1, "wordtemplate2");
ors = (OracleResultSet) opst.executeQuery();
if (ors.next()) {
oracle.sql.BLOB blob2 = ors.getBLOB(1);
System.out.println("blob2 length:" + blob2.length());
b = blob2.getBytes(1, flength); //**从BLOB取出字节流数据
System.out.println("b length::" + b.length);
test.conn.commit();
}
ors.close();
// 将从BLOB读出的字节写入文件
fout.write(b, 0, b.length);
fout.close();
System.out.println("write itotal::" + b.length);
}
catch (Exception e) {
System.out.println("errror :" + e.toString());
e.printStackTrace();
}
finally { //**关闭所有数据联接
test.conn.commit();
}
}
catch(Exception e){
System.out.println(e);
}
}
}
方式二：
package com.lizhe;
import java.io.*;
import java.sql.*;
public class PutImg {
public void putimg() {
try {
Class.forName("org.gjt.mm.mysql.Driver").newInstance();
String url = "jdbc:mysql://localhost/img?user=root&password=root&useUnicode=true&characterEncoding=gbk";
Connection conn = DriverManager.getConnection(url);
Statement stmt = conn.createStatement();
//stmt.execute("insert into imgt (id) values (5)");
stmt.close();
PreparedStatement pstmt = null;
String sql = "";
File file = new File("c:\\blog.jpg");
InputStream photoStream = new FileInputStream(file);
//sql = " UPDATE imgt SET img = ? ";
sql = "INSERT INTO imgtable (img) VALUES (?)";
pstmt = conn.prepareStatement(sql);
pstmt.setBinaryStream(1, photoStream, (int) file.length());
pstmt.executeUpdate();
pstmt.close();
conn.close();
} catch (Exception e) {
e.printStackTrace();
}
}
public static void main(String args[]){
PutImg pi=new PutImg();
pi.putimg();
}
}
InputStream photoStream = new FileInputStream(file);
可以很清楚的看到我们首先把一个图片文件(当然也可以是别的什么文件)转换成了一个二进制输入流
pstmt.setBinaryStream(1, photoStream, (int) file.length());
这个方法建议大家去查一下API文档,第一个参数是通配符位置没的说,第二个参数是流,这和以往的string类型的参数不太一样,
我刚看到的时候也觉得豁然开朗了,但是到这里还没完,不同于以往的字符串参数,这里我们还需要第三个参数来设置这个流的长度,
这里也就是这个文件的长度,导出数据库中的sql,一切都清楚了
INSERT INTO `m_diy` VALUES (2,?\0 JFIF\0 \0H\0H\0\0?? Exif\0\0MM\0*\0\0\0 \0 \0 \0\0\0 \0 \0\0 \0 \0\0\0 \0\0\0b
\0 \0\0\0 \0\0\0j (\0 \0\0\0 \0 \0\0 1\0 \0\0\0 \0\0\0r 2\0 \0\0\0 \0\0\0?i\0 \0\0\0 \0\0\0\0\0\0\0\0\0H\0\0\0
\0\0\0H\0\0\0 Adobe Photoshop CS Windows\02007:03:18 23:08:15\0\0\0\0\0 ?\0 \0\0\0 ??\0\0?\0 \0\0\0 \0\0\0? \0
........等等
其实就是将文件先转换成了二进制的流,然后插入到了sql语言中,向数据库写入了很长很长的一段sql语句
然后我们再来写一个app程序将这个文件读出来,存储成一个图片文件
package com.lizhe;
import java.io.*;
import java.sql.*;
class GetImg {
private static final String URL = "jdbc:mysql://localhost/img?user=root&password=root&useUnicode=true&characterEncoding=gbk";
private Connection conn = null;
private PreparedStatement pstmt = null;
private ResultSet rs = null;
private File file = null;
public void blobRead(String outfile, int picID) throws Exception {
FileOutputStream fos = null;
InputStream is = null;
byte[] Buffer = new byte[4096];
try {
Class.forName("org.gjt.mm.mysql.Driver").newInstance();
conn = DriverManager.getConnection(URL);
pstmt = conn.prepareStatement("select img from imgt where id=?");
pstmt.setInt(1, picID); // 传入要取的图片的ID
rs = pstmt.executeQuery();
rs.next();
file = new File(outfile);
if (!file.exists()) {
file.createNewFile(); // 如果文件不存在，则创建
}
fos = new FileOutputStream(file);
is = rs.getBinaryStream("img");
int size = 0;
while ((size = is.read(Buffer)) != -1) {
// System.out.println(size);
fos.write(Buffer, 0, size);
}
} catch (Exception e) {
System.out.println( e.getMessage());
} finally {
// 关闭用到的资源
fos.close();
rs.close();
pstmt.close();
conn.close();
}
}
public static void main(String[] args) {
try {
GetImg gi=new GetImg();
gi.blobRead("c:/getimgs/1.jpg", 5);
} catch (Exception e) {
System.out.println("[Main func error: ]" + e.getMessage());
}
}
}
这里需要注意的是
is = rs.getBinaryStream("img");
img是数据库中相应的列名,其实和rs.getString()方法差不多,只不过这个方法是读取二进制流的
最后在帖两个bs系统上用的文件给大家参考
通过struts的action向数据库写入二进制图片
/*
* Generated by MyEclipse Struts
* Template path: templates/java/JavaClass.vtl
*/
package com.lizhe.struts.action;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.Statement;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.struts.action.Action;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;
import org.apache.struts.upload.FormFile;
import com.lizhe.struts.form.UpimgForm;
/**
* MyEclipse Struts
* Creation date: 05-18-2007
*
* XDoclet definition:
* @struts.action path="/upimg" name="upimgForm" input="/userhomepage.jsp"
* @struts.action-forward name="userhome" path="/userhomepage.jsp" redirect="true" contextRelative="true"
*/
public class UpimgAction extends Action {
/*
* Generated Methods
*/
/**
* Method execute
* @param mapping
* @param form
* @param request
* @param response
* @return ActionForward
* @throws IOException
* @throws FileNotFoundException
*/
public ActionForward execute(ActionMapping mapping, ActionForm form,
HttpServletRequest request, HttpServletResponse response) throws FileNotFoundException, IOException {
UpimgForm upimgForm = (UpimgForm) form;// TODO Auto-generated method stub
FormFile file=upimgForm.getFile();
InputStream is=file.getInputStream();
try {
Class.forName("org.gjt.mm.mysql.Driver").newInstance();
String url = "jdbc:mysql://localhost/blog?user=root&password=root&useUnicode=true&characterEncoding=gb2312";
Connection conn = DriverManager.getConnection(url);
Statement stmt = conn.createStatement();
//stmt.execute("insert into img (id) values (5)");
stmt.close();
PreparedStatement pstmt = null;
String sql = "";
//File file = new File("c:\\blog.jpg");
//InputStream photoStream = new FileInputStream(file);
//sql = " UPDATE imgt SET img = ? ";
sql = "INSERT INTO img (img) VALUES (?)";
pstmt = conn.prepareStatement(sql);
pstmt.setBinaryStream(1, is, (int) file.getFileSize());
pstmt.executeUpdate();
pstmt.close();
conn.close();
} catch (Exception e) {
e.printStackTrace();
}
return mapping.findForward("userhomepage");
}
}
和app的方式几乎是一样的
第二个文件是通过jsp将数据库中的图片显示在页面上
这个有些不同
<%@ page contentType="text/html;charset=gb2312"%>
<%@ page import="java.sql.*" %>
<%@ page import="java.util.*"%>
<%@ page import="java.text.*"%>
<%@ page import="java.io.*"%>
<%@ page import="java.awt.*"%>
<html>
<body>
<%
Class.forName("org.gjt.mm.mysql.Driver").newInstance();
String url="jdbc:mysql://localhost/img?user=root&password=root";
Connection con = DriverManager.getConnection(url);
String sql = "select * from imgt where id=5";
Statement stmt = con.createStatement();
ResultSet rs = stmt.executeQuery(sql);
if(rs.next()) {
InputStream in = rs.getBinaryStream("img");
ServletOutputStream op = response.getOutputStream();
int len;
byte[] buf=new byte[1024];
while((len= in.read(buf))!=-1) {
op.write(buf, 0, len);
}
op.close();
in.close();
}
rs.close();
stmt.close();
con.close();
%>
</body>
</html>