JDBC 实现增删改查

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public class NoteDAOImpl implements NoteDAO {
// 增加操作
public void insert(Note note) throws Exception {
String sql = "INSERT INTO note(id,title,author,content) VALUES(note_sequ.nextVal,?,?,?)" ;
PreparedStatement pstmt = null ;
DataBaseConnection dbc = null ;
dbc = new DataBaseConnection() ;
try {
pstmt = dbc.getConnection().prepareStatement(sql) ;
pstmt.setString(1,note.getTitle()) ;
pstmt.setString(2,note.getAuthor()) ;
pstmt.setString(3,note.getContent()) ;
pstmt.executeUpdate() ;
pstmt.close() ;
} catch (Exception e) {
// System.out.println(e) ;
throw new Exception("操作中出现错误！！！") ;
} finally {
dbc.close() ;
}
}
// 修改操作
public void update(Note note) throws Exception {
String sql = "UPDATE note SET title=?,author=?,content=? WHERE id=?" ;
PreparedStatement pstmt = null ;
DataBaseConnection dbc = null ;
dbc = new DataBaseConnection() ;
try {
pstmt = dbc.getConnection().prepareStatement(sql) ;
pstmt.setString(1,note.getTitle()) ;
pstmt.setString(2,note.getAuthor()) ;
pstmt.setString(3,note.getContent()) ;
pstmt.setInt(4,note.getId()) ;
pstmt.executeUpdate() ;
pstmt.close() ;
} catch (Exception e) {
throw new Exception("操作中出现错误！！！") ;
} finally {
dbc.close() ;
}
}
// 删除操作
public void delete(int id) throws Exception {
String sql = "DELETE FROM note WHERE id=?" ;
PreparedStatement pstmt = null ;
DataBaseConnection dbc = null ;
dbc = new DataBaseConnection() ;
try {
pstmt = dbc.getConnection().prepareStatement(sql) ;
pstmt.setInt(1,id) ;
pstmt.executeUpdate() ;
pstmt.close() ;
} catch (Exception e) {
throw new Exception("操作中出现错误！！！") ;
} finally {
dbc.close() ;
}
}
// 按ID查询，主要为更新使用
public Note queryById(int id) throws Exception {
Note note = null ;
String sql = "SELECT id,title,author,content FROM note WHERE id=?" ;
PreparedStatement pstmt = null ;
DataBaseConnection dbc = null ;
dbc = new DataBaseConnection() ;
try {
pstmt = dbc.getConnection().prepareStatement(sql) ;
pstmt.setInt(1,id) ;
ResultSet rs = pstmt.executeQuery() ;
if(rs.next()) {
note = new Note() ;
note.setId(rs.getInt(1)) ;
note.setTitle(rs.getString(2)) ;
note.setAuthor(rs.getString(3)) ;
note.setContent(rs.getString(4)) ;
}
rs.close() ;
pstmt.close() ;
} catch (Exception e) {
throw new Exception("操作中出现错误！！！") ;
} finally {
dbc.close() ;
}
return note ;
}
// 查询全部
public List queryAll() throws Exception {
List all = new ArrayList() ;
String sql = "SELECT id,title,author,content FROM note" ;
PreparedStatement pstmt = null ;
DataBaseConnection dbc = null ;
dbc = new DataBaseConnection() ;
try {
pstmt = dbc.getConnection().prepareStatement(sql) ;
ResultSet rs = pstmt.executeQuery() ;
while(rs.next()) {
Note note = new Note() ;
note.setId(rs.getInt(1)) ;
note.setTitle(rs.getString(2)) ;
note.setAuthor(rs.getString(3)) ;
note.setContent(rs.getString(4)) ;
all.add(note) ;
}
rs.close() ;
pstmt.close() ;
} catch (Exception e) {
System.out.println(e) ;
throw new Exception("操作中出现错误！！！") ;
} finally {
dbc.close() ;
}
return all ;
}
// 模糊查询
public List queryByLike(String cond) throws Exception {
List all = new ArrayList() ;
String sql = "SELECT id,title,author,content FROM note WHERE title LIKE ? or AUTHOR LIKE ? or CONTENT LIKE ?" ;
PreparedStatement pstmt = null ;
DataBaseConnection dbc = null ;
dbc = new DataBaseConnection() ;
try {
pstmt = dbc.getConnection().prepareStatement(sql) ;
pstmt.setString(1,"%"+cond+"%") ;
pstmt.setString(2,"%"+cond+"%") ;
pstmt.setString(3,"%"+cond+"%") ;
ResultSet rs = pstmt.executeQuery() ;
while(rs.next()) {
Note note = new Note() ;
note.setId(rs.getInt(1)) ;
note.setTitle(rs.getString(2)) ;
note.setAuthor(rs.getString(3)) ;
note.setContent(rs.getString(4)) ;
all.add(note) ;
}
rs.close() ;
pstmt.close() ;
} catch (Exception e) {
System.out.println(e) ;
throw new Exception("操作中出现错误！！！") ;
} finally {
dbc.close() ;
}
return all ;
}
};

http://talentb.blog.51cto.com/874996/187710