MySQL – iBatis – 文件存储

hotnet

把上传的文件保存到数据库中。数据库的类型为blob和longblob。上传文件的大小大于1M是需要修改MySQL的my.ini配置文件。
修改内容如下：
[mysqld]
max_allowed_packet=1024M
实验步骤：
一、创建数据库表。
脚本：
DROP TABLE IF EXISTS `upload`;
CREATE TABLE `upload` (
`dir` varchar(100) NOT NULL DEFAULT '', /* 保存上传的时间 */
`upload` longblob, /* 存储文件 */
PRIMARY KEY (`dir`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
二、建立Java项目
三、添加MySQL数据库驱动包
四、添加iBatis包
五、添加iBatis主配置文件
代码：
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE sqlMapConfig
PUBLIC "-//ibatis.apache.org//DTD SQL Map Config 2.0//EN"
"http://ibatis.apache.org/dtd/sql-map-config-2.dtd">
<sqlMapConfig>
<transactionManager type="JDBC" commitRequired="false">
<dataSource type="SIMPLE">
<property name="JDBC.Driver" value="com.mysql.jdbc.Driver"/>
<property name="JDBC.ConnectionURL" value="jdbc:mysql://10.32.52.19:3306/iBatis"/>
<property name="JDBC.Username" value="root"/>
<property name="JDBC.Password" value="root"/>
</dataSource>
</transactionManager>
<sqlMap resource="oks-sql.xml"/>
</sqlMapConfig>
六、添加映射文件
代码：
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE sqlMap
PUBLIC "-//ibatis.apache.org//DTD SQL Map 2.0//EN"
"http://ibatis.apache.org/dtd/sql-map-2.dtd">
<sqlMap namespace="sql" >
<typeAlias
alias="upload"
type="Upload" />
<insert
id="up"
parameterClass="upload" >
INSERT INTO upload(dir,upload) values(#dir#,#uploadIn#)
</insert>
<select
id="down"
resultClass="upload" >
select dir,upload as uploadIn from upload
</select>
</sqlMap>
七、编写数据表实体类。
注意：数据库中的Blob类型和longblob类型在实体类中使用byte[]
代码：
import java.io.FileOutputStream;
/**
* TODO Put here a description of what this class does.
*
* @author Administrator.
* Created Sep 12, 2012.
*/
public class Upload {
private String dir;
private byte[] uploadIn;
private FileOutputStream uploadOut;
/**
* TODO Put here a description of what this constructor does.
*
*/
public Upload() {
super();
// TODO Auto-generated constructor stub.
}
public String getDir() {
return this.dir;
}
public void setDir(String dir) {
this.dir = dir;
}
public byte[] getUploadIn() {
return this.uploadIn;
}
public void setUploadIn(byte[] uploadIn) {
this.uploadIn = uploadIn;
}
public FileOutputStream getUploadOut() {
return this.uploadOut;
}
public void setUploadOut(FileOutputStream uploadOut) {
this.uploadOut = uploadOut;
}
}
八、编写连接代码
代码：
private static SqlMapClient sqlMapClient;
static {
Reader reader = null;
try {
reader = Resources.getResourceAsReader("sqlMapConfig.xml");
} catch (IOException exception) {
exception.printStackTrace();
}
// 得到SqlMapClient
sqlMapClient = SqlMapClientBuilder.buildSqlMapClient(reader);
}
九、编写上传文件的代码
代码：
public static void upload() {
try {
sqlMapClient.startTransaction();
Upload upload = new Upload();
upload.setDir(System.currentTimeMillis() + "");
try {
ByteArrayOutputStream bytestream = new ByteArrayOutputStream(); //转换byte数组
FileInputStream in = new FileInputStream("d:/jcifs-1.3.14.jar"); //文件
int ch;
//转换成byte数组
while ((ch = in.read()) != -1) {
bytestream.write(ch);
}
byte imgdata[] = bytestream.toByteArray();
upload.setUploadIn(imgdata);
} catch (IOException exception) {
exception.printStackTrace();
}
sqlMapClient.insert("up", upload);
sqlMapClient.commitTransaction();
} catch (SQLException exception) {
// TODO Auto-generated catch-block stub.
exception.printStackTrace();
}
}
十、编写下载的文件
代码：
public static void down() {
try {
byte[] Buffer = new byte[4096];
int size = 0;
sqlMapClient.startTransaction();
Upload upload = (Upload) sqlMapClient.queryForObject("down");
try {
FileOutputStream fileOutputStream = new FileOutputStream(
"d:/b.jar"); //保存文件
InputStream inputStream = new ByteArrayInputStream(
upload.getUploadIn()); //byte转换为流
while ((size = inputStream.read(Buffer)) != -1) {
System.out.println(size);
fileOutputStream.write(Buffer, 0, size);
}
} catch (FileNotFoundException exception) {
// TODO Auto-generated catch-block stub.
exception.printStackTrace();
} catch (IOException exception) {
// TODO Auto-generated catch-block stub.
exception.printStackTrace();
}
sqlMapClient.commitTransaction();
} catch (SQLException exception) {
// TODO Auto-generated catch-block stub.
exception.printStackTrace();
}
}

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