jdbc实现对CLOB和BLOB数据类型操作

1、 读取操作

CLOB 
 java 代码

 //获得数据库连接
     Connection con = ConnectionFactory.getConnection();
     con.setAutoCommit(false);
     Statement st = con.createStatement();
     //不需要“for update”
     ResultSet rs = st.executeQuery("select CLOBATTR from TESTCLOB where ID=1");
     if (rs.next())
     {
         java.sql.Clob clob = rs.getClob("CLOBATTR");
         Reader inStream = clob.getCharacterStream();
         char[] c = new char[(int) clob.length()];
         inStream.read(c);
         //data是读出并需要返回的数据，类型是String
         data = new String(c);
         inStream.close();
     }
     inStream.close();
     con.commit();
     con.close();

BLOB 
java 代码

 //获得数据库连接
     Connection con = ConnectionFactory.getConnection();
     con.setAutoCommit(false);
     Statement st = con.createStatement();
     //不需要“for update”
     ResultSet rs = st.executeQuery("select BLOBATTR from TESTBLOB where ID=1");
     if (rs.next())
     {
         java.sql.Blob blob = rs.getBlob("BLOBATTR");
         InputStream inStream = blob.getBinaryStream();
         //data是读出并需要返回的数据，类型是byte[]
         data = new byte[input.available()];
         inStream.read(data);
         inStream.close();
     }
     inStream.close();
     con.commit();
     con.close();

2、写入操作 

CLOB 
java 代码

 //获得数据库连接
     Connection con = ConnectionFactory.getConnection();
     con.setAutoCommit(false);
     Statement st = con.createStatement();
     //插入一个空对象empty_clob()
     st.executeUpdate("insert into TESTCLOB (ID, NAME, CLOBATTR) values (1, "thename", empty_clob())");
     //锁定数据行进行更新，注意“for update”语句
     ResultSet rs = st.executeQuery("select CLOBATTR from TESTCLOB where ID=1 for update");
     if (rs.next())
     {
         //得到java.sql.Clob对象后强制转换为oracle.sql.CLOB
         oracle.sql.CLOB clob = (oracle.sql.CLOB) rs.getClob("CLOBATTR");
         Writer outStream = clob.getCharacterOutputStream();
         //data是传入的字符串，定义：String data
         char[] c = data.toCharArray();
         outStream.write(c, 0, c.length);
     }
     outStream.flush();
     outStream.close();
     con.commit();
     con.close();

   
BLOB 
java 代码

 //获得数据库连接
     Connection con = ConnectionFactory.getConnection();
     con.setAutoCommit(false);
     Statement st = con.createStatement();
     //插入一个空对象empty_blob()
     st.executeUpdate("insert into TESTBLOB (ID, NAME, BLOBATTR) values (1, "thename", empty_blob())");
     //锁定数据行进行更新，注意“for update”语句
     ResultSet rs = st.executeQuery("select BLOBATTR from TESTBLOB where ID=1 for update");
     if (rs.next())
     {
         //得到java.sql.Blob对象后强制转换为oracle.sql.BLOB
         oracle.sql.BLOB blob = (oracle.sql.BLOB) rs.getBlob("BLOBATTR");
         OutputStream outStream = blob.getBinaryOutputStream();
         //data是传入的byte数组，定义：byte[] data
         outStream.write(data, 0, data.length);
     }
     outStream.flush();
     outStream.close();
     con.commit();
     con.close();

3、读写CLOB/BLOB数据到文件

TNS：

# tnsnames.ora Network Configuration File: d:\oracle\product\10.2.0\client_1\NETWORK\ADMIN\tnsnames.ora 
 # Generated by Oracle configuration tools. 

 ORADB = 
     (DESCRIPTION = 
         (ADDRESS_LIST = 
             (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.1.100)(PORT = 1521)) 
         ) 
         (CONNECT_DATA = 
             (SID = ORCL) 
         ) 
     ) 

 MYORCL = 
     (DESCRIPTION = 
         (ADDRESS_LIST = 
             (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.1.100)(PORT = 1521)) 
         ) 
         (CONNECT_DATA = 
             (SERVICE_NAME = myorcl) 
         ) 
     ) 

Table：

create table TEST_ORALOB 
 ( 
     ID         VARCHAR2(20), 
     TSBLOB BLOB not null, 
     TSCLOB CLOB not null 
 )

测试代码：

package lavasoft.oralob.common; 

import oracle.sql.BLOB; 

import java.io.*; 
import java.sql.*; 

/** 
 * JDBC读写Oracle10g的CLOB、BLOB 
 * 
 */ 
public class TestOraLob { 

         public static void main(String[] args) { 
                 insertBlob(); 
                 queryBlob(); 
         } 

         public static void insertBlob() { 
                 Connection conn = DBToolkit.getConnection(); 
                 PreparedStatement ps = null; 
                 try { 
                         String sql = "insert into test_oralob (ID, TSBLOB, TSCLOB) values (?, ?, ?)"; 
                         ps = conn.prepareStatement(sql); 
                         ps.setString(1, "100"); 
                         //设置二进制BLOB参数 
                         File file_blob = new File("C:\\a.jpg"); 
                         InputStream in = new BufferedInputStream(new FileInputStream(file_blob)); 
                         ps.setBinaryStream(2, in, (int) file_blob.length()); 
                         //设置二进制CLOB参数 
                         File file_clob = new File("c:\\a.txt"); 
                         InputStreamReader reader = new InputStreamReader(new FileInputStream(file_clob)); 
                         ps.setCharacterStream(3, reader, (int) file_clob.length()); 
                         ps.executeUpdate(); 
                         in.close(); 
                 } catch (IOException e) { 
                         e.printStackTrace(); 
                 } catch (SQLException e) { 
                         e.printStackTrace(); 
                 } finally { 
                         DBToolkit.closeConnection(conn); 
                 } 
         } 

         public static void queryBlob() { 
                 Connection conn = DBToolkit.getConnection(); 
                 PreparedStatement ps = null; 
                 Statement stmt = null; 
                 ResultSet rs = null; 
                 try { 
                         String sql = "select TSBLOB from TEST_ORALOB where id ='100'"; 
                         stmt = conn.createStatement(); 
                         rs = stmt.executeQuery(sql); 
                         if (rs.next()) { 
                                 //读取Oracle的BLOB字段 
                                 InputStream in = rs.getBinaryStream(1); 
                                 File file = new File("c:\\a1.jpg"); 
                                 OutputStream out = new BufferedOutputStream(new FileOutputStream(file)); 
                                 byte[] buff1 = new byte[1024]; 
                                 for (int i = 0; (i = in.read(buff1)) > 0;) { 
                                         out.write(buff1, 0, i); 
                                 } 
                                 out.flush(); 
                                 out.close(); 
                                 in.close(); 
                                 //读取Oracle的CLOB字段 
                                 char[] buff2 = new char[1024]; 
                                 File file_clob = new File("c:\\a1.txt"); 
                                 OutputStreamWriter writer = new OutputStreamWriter(new FileOutputStream(file_clob)); 
                                 Reader reader = rs.getCharacterStream(1); 
                                 for (int i = 0; (i = reader.read(buff2)) > 0;) { 
                                         writer.write(buff2, 0, i); 
                                 } 
                                 writer.flush(); 
                                 writer.close(); 
                                 reader.close(); 
                         } 
                         rs.close(); 
                         stmt.close(); 
                 } catch (IOException e) { 
                         e.printStackTrace(); 
                 } catch (SQLException e) { 
                         e.printStackTrace(); 
                 } finally { 
                         DBToolkit.closeConnection(conn); 
                 } 
         } 
 }

注：如果是具体的字符串写入CLOB字段，简化写法：

  //设置二进制CLOB参数    
   String xxx = "abcdefg"; 
   ps.setCharacterStream(3, new StringReader(xxx), xxx.getBytes("GBK").length);    
   ps.executeUpdate();    
   in.close();