|
|
我们要做的是将一张图片存入Mysql中,在Mysql中用Blob 来存储图片和音频等大的数据项.Blob 按其容量可分为四种,分别为:tinyblob,blob ,mediumblob, longblob.他们的大小分别为:256B,64KB,16MB,4GB.除了容量不同外,这四种的用法一个样.我们这次将用Blob.
首先来创建我们的数据库,
create database Image;
use Image;
create table country (
id int primary key auto_increment,
name varchar(30),
flag blob,
description varchar(255)
);
数据库创建完毕,下面是Java 的程序代码,它实现的功能是从一个目录中读入一张图片(china.gif) ,然后在把它输出在另一个目录中(1.gif).
*****************************************************************************************************
import java.sql.*;
import java.io.*;
public class TestImage {
private static final String URL = "jdbc:mysql://localhost/Image?user=root&password=root&useUnicode=true";
private Connection conn = null;
private PreparedStatement pstmt = null;
private ResultSet rs = null;
private File file = null;
private InputStream inputImage = null;
private OutputStream outputImage = null;
public void blobInsert(String infile) {
try {
Class.forName("com.mysql.jdbc.Driver");
System.out.println("Driver loaded!");
conn = DriverManager.getConnection(URL);
System.out.println("Database connected!");
pstmt = conn
.prepareStatement("insert into Country (name,flag,description) values (?,?,?)");
pstmt.setString(1, "china");
file = new File(infile);
try {
inputImage = new FileInputStream(file);
} catch (FileNotFoundException e) {
e.printStackTrace();
}
pstmt.setBinaryStream(2, inputImage, (int) (file.length()));
pstmt.setString(3, "A flag of China");
pstmt.executeUpdate();
System.out.println("commit successfully");
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
} finally {
try {
inputImage.close();
pstmt.close();
conn.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}
public void readBolb(String path, int id) {
InputStream is = null;
byte[] buffer = new byte[4096];
try {
Class.forName("com.mysql.jdbc.Driver");
System.out.println("Driver loaded!");
conn = DriverManager.getConnection(URL);
System.out.println("Database connected!");
pstmt = conn
.prepareStatement("select flag from Country where id =?");
System.out.println("select ok");
pstmt.setInt(1, id);
rs = pstmt.executeQuery();
rs.next();
file = new File(path);
if (!file.exists()) {
try {
file.createNewFile();
} catch (IOException e) {
e.printStackTrace();
}
}
try {
outputImage = new FileOutputStream(file);
System.out.println(outputImage.toString());
} catch (FileNotFoundException e) {
e.printStackTrace();
}
Blob blob = rs.getBlob("flag");
is = blob.getBinaryStream();
try {
System.out.println(is.available());
} catch (IOException e2) {
e2.printStackTrace();
}
try {
System.out.println(is.available());
} catch (IOException e1) {
e1.printStackTrace();
}
int size = 0;
try {
while ((size = is.read(buffer)) != -1) {
System.out.println(size);
outputImage.write(buffer, 0, size);
}
} catch (IOException e) {
e.printStackTrace();
}
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
} finally {
try {
is.close();
outputImage.close();
pstmt.close();
conn.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}
public static void main(String[] args) {
new TestImage().blobInsert("c://TDdownload//china.gif");
new TestImage().readBolb("c://1.gif", 1);
}
}
程序执行完你将在相应的目录下看到一张输出的图片.同时在Mysql 客户端使用:select * from country;将显示一堆的乱麻,这就正常.说明图片已经存入Mysql 中.到次本次试验完毕!
程序猿的技术大观园：www.javathinker.net
|
|
Java技术网站 → 『 Java开发技术 』 → 『 Java编程技术专题 』 → 通过Java编程向数据库存取图片
消息
查看
搜索
好友
邮件
复制
引用
IP: 已设置保密
