oracle本身支持对大数据类型的各种处理，但是平常大家可能用的不多，其中clob(一般用于大类型的字符型的存取)和blob(一般用于大类型的二进制类型的存取)我想应该就是用的比较少的。所以我写下这篇博文，主要是对这两个数据类型的文件进行的操作，如，保存这类文件进入数据库，读取这类文件到本地磁盘。
本来按照老习惯是该先上效果图的，可惜我的机器现在巨卡，10g跑起来基本让我泪流满面，所以我就偷下懒，图就给省略了 -_-!
第一步，新建一个java项目(为啥是java项目而不是web呢，主要因为它便于测试，出效果也快...)orclTest
第二步，新建一个数据库连接的类，我这里是com.test.InitDB.java，代码如下：
class InitDB{
private static Connection con = null;
private static Statement stmt = null;
private static ResultSet rs = null;
//链接oracle数据库
InitDB()
{
try
{
Class.forName("oracle.jdbc.driver.OracleDriver").newInstance();
String url = "jdbc:oracle:thin:@localhost:1521:YYSMID";
String user = "zhangsan";
String password = "Lc123456";
con = (Connection) DriverManager.getConnection(url, user, password);
InitDB.setCon(con);
}
catch (Exception e)
{
e.printStackTrace();
}
}
public void closCon()
{
try
{
con.close();
}
catch (Exception e)
{
e.printStackTrace();
}
}
public void stmt()
{
try
{
con.close();
}
catch (Exception e)
{
e.printStackTrace();
}
}
public void rs()
{
try
{
con.close();
}
catch (Exception e)
{
e.printStackTrace();
}
}
public static Connection getCon()
{
return con;
}
public static void setCon(Connection con)
{
InitDB.con = con;
}
public static ResultSet getRs()
{
return rs;
}
public static void setRs(ResultSet rs)
{
InitDB.rs = rs;
}
public static Statement getStmt()
{
return stmt;
}
public static void setStmt(Statement stmt)
{
InitDB.stmt = stmt;
}
}
第三步，以及接下来的几步，我们来分别编写clob和blob的插入数据库和读出数据库的代码，新建com.test.InsertBlobData.java，顾名思义，它是用来插入blob类型数据的类。代码如下：
class InsertBlobData{
private ResultSet rs = null;
private InitDB idb = null;
InsertBlobData()
{
idb = new InitDB();
}
public void insertBlob(String sql1) throws SQLException
{
Connection con = idb.getCon();
try
{
con.setAutoCommit(false);// 不设置自动提交
BLOB blob = null; // 插入空的Blob
PreparedStatement pstmt = con
.prepareStatement("insert into cdl_test(sid,img) values(?,empty_blob())");
pstmt.setString(1, "100");
pstmt.executeUpdate();
pstmt.close();
rs = con.createStatement().executeQuery(sql1);
while (rs.next())
{
System.out.println("rs length is:");
oracle.sql.BLOB b = (oracle.sql.BLOB) rs.getBlob("img");
System.out.println("cloblength is:" + b.getLength());
File f = new File("d:\\1.jpg"); //1.jpg一张QQ的截图
System.out.println("file path is:" + f.getAbsolutePath());
BufferedInputStream in = new BufferedInputStream(
new FileInputStream(f));
BufferedOutputStream out = new BufferedOutputStream(b
.getBinaryOutputStream());
int c;
while ((c = in.read()) != -1)
{
out.write(c);
}
in.close();
out.close();
}
con.commit();
}
catch (Exception e)
{
con.rollback();// 出错回滚
e.printStackTrace();
}
}
}
第四步，新建com.test.InsertClobData.java，用于插入clob数据类型的，代码如下：
class InsertClobData
{
private ResultSet rs = null;
private InitDB idb = null;
InsertClobData()
{
idb = new InitDB();
}
public void insertClob(String sql1) throws SQLException
{
Connection con = idb.getCon();
try
{
con.setAutoCommit(false);// 不设置自动提交
BLOB blob = null; // 插入空的Clob
PreparedStatement pstmt = con
.prepareStatement("insert into cdl_test(sid,doc) values(?,empty_clob())");
pstmt.setString(1, "101");
pstmt.executeUpdate();
pstmt.close();
rs = con.createStatement().executeQuery(sql1);
while (rs.next())
{
System.out.println("sdfasdfas");
oracle.sql.CLOB cb = (oracle.sql.CLOB) rs.getClob("doc");
File f = new File("d:\\1.txt"); //1.txt一本小说《风云》马荣成
System.out.println("file path is:" + f.getAbsolutePath());
BufferedWriter out = new BufferedWriter(cb
.getCharacterOutputStream());
BufferedReader in = new BufferedReader(new FileReader(f));
int c;
while ((c = in.read()) != -1)
{
out.write(c);
}
in.close();
out.close();
}
con.commit();
}
catch (Exception e)
{
con.rollback();// 出错回滚
e.printStackTrace();
}
}
}
第五步，新建com.test.ReadBlobData.java，用于读取blob类型的数据，代码如下：
class ReadBlobData
{
private ResultSet rs = null;
private InitDB idb = null;
ReadBlobData()
{
idb = new InitDB();
}
public void getBlob(String sql2) throws SQLException
{
Connection con = idb.getCon();
con.setAutoCommit(false);
try
{
System.out.println("sq2 is:" + sql2);
System.out.println("stmt is:" + con);
rs = con.createStatement().executeQuery(sql2);
while (rs.next())
{
System.out.println("rs length is:");
Blob b = (Blob) rs.getBlob("img");
File f = new File("D:\\1.jpg");
FileOutputStream fos = new FileOutputStream(f);
InputStream is = b.getBinaryStream();// 读出数据后转换为二进制流
byte[] data = new byte[1024];
while (is.read(data) != -1)
{
fos.write(data);
}
fos.close();
is.close();
}
con.commit();// 正式提交
}
catch (Exception e)
{
e.printStackTrace();
}
finally
{
// rs.close();
}
}
}
第六步，新建com.test.ReadClobData.java，用于读取clob类型的数据，代码如下：
class ReadClobData
{
private ResultSet rs = null;
private InitDB idb = null;
ReadClobData()
{
idb = new InitDB();
}
public void getClob(String sql2) throws SQLException
{
Connection con = idb.getCon();
try
{
con.setAutoCommit(false);// 不设置自动提交
System.out.println("sq2 is:" + sql2);
rs = con.createStatement().executeQuery(sql2);
while (rs.next())
{
oracle.sql.CLOB clob = (oracle.sql.CLOB) rs.getClob("doc");
File f = new File("d:\\1.txt");
BufferedReader in = new BufferedReader(clob
.getCharacterStream());
// setCharacterStream()方法，可用于将CLOB字段与字节流相关联，
BufferedWriter out = new BufferedWriter(new FileWriter(f));
int c;
while ((c = in.read()) != -1)
{
out.write(c);
}
out.close();
in.close();
}
con.commit();// 正式提交
rs.close();
}
catch (Exception e)
{
e.printStackTrace();
con.rollback();
}
}
}
最后，就是新建测试类了，每每用着main方法，我就感觉这世界是多么的有爱啊，junit什么的，最讨厌了.....
public class TestBlob_Clob
{
public static void main(String[] args)
{
String sql1 = "select * from cdl_test for update";// 悲观锁锁定需更新的行
String sql2 = "select * from cdl_test";
System.out.println("\t\t\t欢迎使用:");
System.out.println("1:插入图片");
System.out.println("2:插入文本");
System.out.println("3:读取图片");
System.out.println("4:读取文本");
System.out.println("5:退出");
System.out.println("请选择:");
while (true)
{
try
{
Scanner sc = new Scanner(System.in);
int i = sc.nextInt();
System.out.println("sss:" + i);
switch (i)
{
case 1:
InsertBlobData isd = new InsertBlobData();
//插入图片
isd.insertBlob(sql1);
break;
case 2:
InsertClobData icd = new InsertClobData();
//插入小说
icd.insertClob(sql1);
break;
case 3:
ReadBlobData rb = new ReadBlobData();
//得到图片
rb.getBlob(sql2);
break;
case 4:
ReadClobData rc = new ReadClobData();
//得到小说
rc.getClob(sql2);
break;
case 5:
System.exit(0);
}
}
catch (Exception e)
{
e.printStackTrace();
}
}
}
}