找到解决方法了.
InputStream in = rs.getBinaryStream("fcontent");
String body = null;
DefaultStyledDocument styled = new DefaultStyledDocument();
new RTFEditorKit().read(in, styled, 0);
body = new String(styled.getText(0, styled.getLength()).getBytes(
"ISO8859_1"));
System.out.println("body--------" + body);