jdbc 操作 mysql 增删改查

public class AtfireDao {

// 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 ;

}

}