// 查询一个学生的所有信息
public Student selectSt(String username) {
Connection conn = null;
PreparedStatement st = null;
ResultSet rs = null;
Student student = null;
String sql = "select * from student where username=? ";
try {
student = new Student();
conn = JdbcUtil.getConnection();
st = conn.prepareStatement(sql);
st.setString(1, username);
rs = st.executeQuery();
while (rs.next()) {
if (username.equals(rs.getString("username"))) {
student.setId(rs.getInt("id"));
student.setUsername(rs.getString("username"));
student.setEmail(rs.getString("email"));
student.setName(rs.getString("name"));
student.setPhoto(rs.getString("photo"));
student.setAnswer(rs.getString("answer"));
student.setProtection(rs.getString("protection"));
student.setTel(rs.getString("tel"));
student.setView_photo(rs.getString("view_photo"));
}
}
} catch (SQLException e) {
e.printStackTrace();
} finally {
JdbcUtil.release(conn, st, rs);
}
return student;
}
// 查询所有学生信息 ,以注册时间为顺序
public List<Student> selectAllSt(Page page) {
Connection conn = null;
PreparedStatement st = null;
ResultSet rs = null;
List<Student> list = null;
String sql = "select * from student order by register_date desc limit ?,?";
try {
conn = JdbcUtil.getConnection();
list = new ArrayList<Student>();
st = conn.prepareStatement(sql); // 预编译SQL语句
st.setInt(1, page.getStart());
st.setInt(2, page.getShowCount());
rs = st.executeQuery();
while (rs.next()) { // 逐行查询
Student student = new Student();
student.setId(rs.getInt("id"));
student.setUsername(rs.getString("username"));
student.setSex(rs.getString("sex"));
student.setEmail(rs.getString("email"));
student.setTel(rs.getString("tel"));
student.setName(rs.getString("name"));
student.setRegister_date(rs.getDate("register_date"));
list.add(student);
}
} catch (SQLException e) {
e.printStackTrace();
} finally {
JdbcUtil.release(conn, st, rs);
}
return list;
}
// 更新一个学生的所有信息
public boolean updateSt(Student student) {
Connection conn = null;
PreparedStatement st = null;
ResultSet rs = null;
String sql = "update student set name=?,tel=?,email=? where id=?";
try {
conn = JdbcUtil.getConnection();
st = conn.prepareStatement(sql);
st.setString(1, student.getName());
st.setString(2, student.getTel());
st.setString(3, student.getEmail());
st.setInt(4, student.getId());
st.executeUpdate();
} catch (SQLException e) {
e.printStackTrace();
return false;
} finally {
JdbcUtil.release(conn, st, rs);
}
return true;
}