oracle存储大数据类型(Clob/Blob)

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();
             }
         }
     }
 }