一、Oracle的BFILE数据类型简介

1. BFILE数据类型介绍

BFILE类型是Oracle数据库中LOB类型的一种
BFILE字段存放指向操作系统文件的指针
BFILE字段只支持只读访问
BFILE字段支持最大2^64-1 bytes文件
BFILE字段指向的文件不是数据库的一部份，只能在数据库外维护
对BFILE字段操作要使用BFILENAME函数
读取BFILE字段需要使用DBMS_LOB包

2、BFILENAME函数介绍

BFILENAME函数语法如下

BFILENAME函数有两个参数 'directory'，'filename'
'directory'参数是大小写敏感的
'directory'参数所指定的目录必须在dba_directories中存在

二、创建包含BFILE字段的表

1、新建目录/tmp/bfile

[oracle@localhost ~]$ mkdir -p /tmp/bfile/

2、创建directory

SQL> create directory BFILEDIR as '/tmp/bfile';

3、新建两个文件

[oracle@localhost ~]$ cd /tmp/bfile/
[oracle@localhost bfile]$ pwd
/tmp/bfile
[root@db2 bfile]# ls -l
total 8
-rw-r--r-- 1 root root 51 Nov  7 18:10 aaa.txt
-rw-r--r-- 1 root root 52 Nov  7 18:11 bbb.txt
[oracle@localhost bfile]$ cat aaa.txt 
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
[oracle@localhost bfile]$ cat bbb.txt 
aaaaaaa
bbbbbb
ccccccc
dddddddd
111111
22222
333333

4、创建表

SQL> CREATE TABLE "TANGYIBO"."t_oralce_bfile" ( "id" NUMBER NOT NULL ENABLE,"file" BFILE, PRIMARY KEY ("id")) ;
Table created.

5、初始化表数据

SQL>INSERT INTO "TANGYIBO"."t_oralce_bfile" ("id", "file") VALUES ('1', BFileName('BFILEDIR', 'aaa.txt'));
SQL>INSERT INTO "TANGYIBO"."t_oralce_bfile" ("id", "file") VALUES ('2', BFileName('BFILEDIR', 'bbb.txt'));
SQL> commit;

三、JDBC方式读取oracle的BFILE类型数据

 private void getBFile() {
        Connection conn = null;
        Statement stmt = null;
        ResultSet rs = null;
        try
        {
            String driver = "oracle.jdbc.driver.OracleDriver";
            String url = "jdbc:oracle:thin:@127.0.0.1:1521:orcl";
            Class.forName(driver);
            conn = DriverManager.getConnection(url, "tangyibo", "123456");
            System.out.println("connect");

            stmt = conn.createStatement();
            String sql = "SELECT \"id\",\"file\" FROM \"TANGYIBO\".\"t_oralce_bfile\" ";
            rs = stmt.executeQuery(sql);
            System.out.println("sql="+sql);
            while (rs.next()) { 
                BFILE b = (BFILE)rs.getObject(1);
                OutputStream ops = null;
                InputStream ips = null;
 
                //getName() only for BFILE
                File file = new File("d:"+File.separator+b.getName());
                try {
                    //fileExists() only for BFILE
                    System.out.println("isFileExist = "+b.fileExists());

                    //For BFILE,must open File,and close File after its operation 
                    //for BLOB,needn’t openFile() and closeFile()
                    b.openFile();                  
                    ips = b.getBinaryStream();
                    byte[] buffer =new byte[b.getBytes().length];//
                    ops = new FileOutputStream(file);
                    //将文件写到硬盘
                    for (int i; (i = ips.read(buffer)) > 0;) {                      
                        ops.write(buffer, 0, i);
                        ops.flush();
                    }

                    b.closeFile();
                }
                catch (Exception ex) {
                    ex.printStackTrace(System.out);
                }
                finally {
                    ips.close();
                    ops.close();
                }
            }
        }
        catch (Exception ex) {
            ex.printStackTrace(System.out);
        }
        finally {
            try {
                if(rs!=null) {
                   rs.close();
                }
                if(stmt!=null) {
                   stmt.close();
                }
                if(conn!=null) {
                   conn.close();
                }
            }
            catch (SQLException ex) {
               ex.printStackTrace(System.out);
            }
        }
}