为了使用JSP灵活需要把各种文件储存在数据库中然后需要的时候将它读取出来显示到客户端这些文件包括文本图片音乐等人们统称为二进制文件。下面学步园小编来讲解下java怎样操作mysql存储读取图片？
java怎样操作mysql存储读取图片
1在mysql中创建一个表picture_db
createtablepicture_db(
file_namevarchar(255)notnull,
contentlongblob,
primarykey(file_name));
2java写储存文件的代码
importjava.sql.*;
importjava.io.*;
importjava.nio.*;
publicclassUploadImage{
protectedConnectiondbConnection;
protectedStringdriverName="com.mysql.jdbc.Driver";
protectedStringdbURL="jdbc:mysql://localhost:3306/sample_db";
protectedStringuserID="root";
protectedStringpasswd="yourpassword";
publicbooleanstoreImage(Stringsqlstr,Filefile){
try{
FileInputStreamfin=newFileInputStream(file);
ByteBuffernbf=ByteBuffer.allocate((int)file.length());
byte[]array=newbyte[1024];
intoffset=0,length=0;
while((length=fin.read(array))>0){
if(length!=1024)
nbf.put(array,0,length);
else
nbf.put(array);
offset+=length;
}
fin.close();
byte[]content=nbf.array();
returnsetImage(sqlstr,content);
}catch(FileNotFoundExceptione){
e.printStackTrace();
}catch(IOExceptione){
e.printStackTrace();
}
returnfalse;
}
privatebooleansetImage(Stringsqlstr,byte[]in){
booleanflag=false;
if(sqlstr==null)
sqlstr="select*frompicture_db";
try{
Class.forName(driverName);
dbConnection=DriverManager.getConnection(dbURL,userID,passwd);
Statementstmt=dbConnection.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_UPDATABLE);
ResultSetrs=stmt.executeQuery(sqlstr);
if(rs.next()){
rs.updateBytes(2,in);
rs.updateRow();
}
else{
rs.moveToInsertRow();
rs.updateString(1,"01");
rs.updateBytes(2,in);
rs.insertRow();
}
rs.close();
flag=true;
}catch(Exceptione){
e.printStackTrace();
}
returnflag;
}
publicstaticvoidmain(String[]args){
UploadImageupload=newUploadImage();
try{
Filefile=newFile("01.jpg");
if(upload.storeImage(null,file))
System.out.print("ture");
else
System.out.print("False");
}catch(Exceptione){
e.printStackTrace();
}
}
}
如果执行成功的话系统打印true否则false
java怎样操作mysql存储读取图片
3就是将图片读取出来与储存的过程相反先建立连接创建数据库查询JDBC对象使用该语句来返回二进制结果保存到文件中
<%@pagecontentType="image/jpeg;charset=GB2312"%>
<%@pageimport="java.sql.*"%><%@pageimport="java.io.*"%>
<%@pageimport="com.sun.image.codec.jpeg.*"%>
<%@pageimport="javax.imageio.*"%>
<%@pageimport="java.awt.image.*"%>
<% StringshowImage="select*frompicture_dbwherefile_name='01'"; Connectionconn=null; BufferedInputStreaminputImage=null;StringdriverName="com.mysql.jdbc.Driver"; StringdbURL="jdbc:mysql://localhost:3306/sample_db"; StringuserID="root"; Stringpasswd="yourpassword";try{ Class.forName(driverName).newInstance(); conn=DriverManager.getConnection(dbURL,userID,passwd);Statementst=conn.createStatement(); ResultSetrs=st.executeQuery(showImage); while(rs.next()){ Blobblob=(Blob)rs.getBlob("content"); inputImage=newBufferedInputStream(blob.getBinaryStream()); }BufferedImageimage=null; image=ImageIO.read(inputImage); ServletOutputStreamsos=response.getOutputStream(); JPEGImageEncoderencoder=JPEGCodec.createJPEGEncoder(sos); encoder.encode(image); inputImage.close(); }catch(SQLExceptione) { e.printStackTrace(); }catch(IOExceptione){ e.printStackTrace(); } %>
以上就是关于“java怎样操作mysql存储读取图片”的内容，希望对大家有用。更多资讯请关注学步园。学步园，您学习IT技术的优质平台!