Java从入门到精通——数据库篇之JAVA中的对Oracle数据库操作

/**	 * 根据用户代码查询
* @param userId
* @return 如果存在返回User 如果不存在则返回Null
*/
public User findUserById(String userId){
//sql语句
String sql="select user_id,user_name,password,contact_tel,email,create_date from t_user where user_id=?";
//创建Connection对象
Connection conn=null;
//创建PreparedStatement对象
PreparedStatement pstmt=null;
//创建ResultSet对象
ResultSet rs=null;
User user=null;

try{
conn=DbUtil.getConnection();
//创建包含带参数占位符的 SQL 语句的 PreparedStatement 对象：
pstmt=conn.prepareStatement(sql);
//给每一个参数传值
pstmt.setString(1, userId);
//执行查询语句
rs=pstmt.executeQuery();
//取出数据
if(rs.next()){
user=new User();
user.setUserId(rs.getString("user_id"));
user.setUserName(rs.getString("user_name"));
user.setPassword(rs.getString("password"));
user.setContactTel(rs.getString("contact_tel"));
user.setEmail(rs.getString("email"));
user.setCreateDate(rs.getTimestamp("create_date"));
}
}catch(SQLException e){
e.printStackTrace();
}finally{
DbUtil.close(rs);
DbUtil.close(pstmt);
DbUtil.close(conn);
}
return user;
}

public void addUser(User user){
//SQL语句
String sql= "insert into t_user (user_id, user_name, password, contact_tel, email, create_date) " +" values (?, ?, ?, ?, ?, ?)";
//定义数据库连接
Connection conn=null;
//定义一个PreparedStatement对象
PreparedStatement pstmt=null;
try{

conn=DbUtil.getConnection();
//创建包含带参数占位符的 SQL 语句的 PreparedStatement 对象：
pstmt=conn.prepareStatement(sql);
//给每一个参数传值
pstmt.setString(1, user.getUserId());
pstmt.setString(2, user.getUserName());
pstmt.setString(3,user.getPassword());
pstmt.setString(4,user.getContactTel());
pstmt.setString(5,user.getEmail());
pstmt.setTimestamp(6, new Timestamp(new Date().getTime()));
//执行语句
pstmt.executeUpdate();
}catch(SQLException e){
e.printStackTrace();
}finally{
DbUtil.close(pstmt);
DbUtil.close(conn);
}
}