解析使用jdbc,hibernate处理clob/blob字段的详解

//插入空值
conn.setAutoCommit(false);
String sql = "insert into file(name,file_content) values("jack",EMPTY_CLOB());
PreparedStatement pstmt = conn.prepareStatement(sql);
pstmt.executeUpdate();
//锁住此行
String sql = "select file_content from file where name='jack' for update";
PreparedStatement pstmt = conn.prepareStatement(sql);
ResultSet rs = pstmt.executeQuery();
oracle.sql.Clob clob = (oracle.sql.Clob)rs.getClob(1);
java.io.OutputStream writer = clob.getAsciiOutputStream();
byte[] temp = newFileContent.getBytes();
writer.write(temp);
writer.flush();
writer.close();
//
pstmt.close();

读取内容:
oracle.sql.Clob clob = rs.getClob("file_content");
if(null!=clob)
{
     Reader is = clob.getCharacterStream();
     BufferedReader br = new BufferedReader(is);
     String s = br.readLine();
    while (s != null)
    {
        content += s + "<br>"; 
        s = br.readLine();
    }
}

conn.setAutoCommit(false);
String sql = "insert into photo(name,photo) values("jack",empty_blob());
pstmt = conn.prepareStatement(sql);
pstmt = conn.executeUpdate();
//
sql = "select photo from photo where name='jack'";
pstmt = conn.prepareStatement(sql);
rs = pstmt.executeQuery(sql);
if(rs.next())
     oracle.sql.Blob blob = (oracle.sql.Blob)rs.getBlob(1);
//write to a file
File file = new File("c:\\test.rar");
FileInputStream fin = new FileInputStream(file);
OutputStream out = blob.getBinaryOutputStream();
int count = -1, total = 0;
byte[] data = new Byte[blob.getBufferSize()];
while ((count = fin.read(data)) != -1)
{
         total += count;
         out.write(data, 0, count);
}

MyFile file = new Myfile();
file.setName("jack");
file.setContent(hibernate.createClob(""));
session.save(file);
session.flush();
session.refresh(file,LockMode.UPGRADE);
oracle.sql.Clob clob = (oracle.sql.Clob)file.getContent();
Writer pw = clob.getCharacterOutputStream();
pw.write(longText);//写入长文本
pw.close();
session.close();

原理基本相同：
Photo photo = new Photo();
photo.setName("jack");
photo.setPhoto(hibernate.createBlob(""))://放一个空值
session.save(photo);
session.flush();
//
session.refresh(photo,LockMode.UPGRADE); //锁住此对象
oracle.sql.Blob blob = photo.getPhoto();//取得此blob的指针
OutputStream out = blob.getBinaryOutputStream();   
//写入一个文件
File f = new File("c:\\test.rar");
FileInputStream fin = new FileInputStream(f);   
int count = -1, total = 0;
byte[] data = new byte[(int)fin.available()];
out.write(data);     
fin.close();
out.close();
session.flush();