数据库大作业

public class DbUtil {
	//com.microsoft.sqlserver.jdbc.SQLServerDriver
    //数据库驱动的名字（1.6 还是 1.8 之后就不需要了，这里还是加上吧）
	String driverName = "com.mysql.jdbc.Driver";
	//jdbc:sqlserver://127.0.0.1:1433;DatabaseName=demo
    //连接数据库的地址，前面的不用改，这里要改的就是后面的 demo 换成你的数据库名字（我上面的是 demo）
	String dbURL = "jdbc:mysql://localhost:3306/demo";
    //你的数据库的帐号
	String userName = "root";
    //装 mysql 时设置的密码
	String userPwd = "admin"; 

	public Connection getCon() throws ClassNotFoundException, SQLException {
		Class.forName(driverName);
		Connection conn = DriverManager.getConnection(dbURL, userName, userPwd);
		return conn;
	}

	public void closeCon(Connection conn) throws SQLException {
		if (conn != null)
			conn.close();
	}

	public static void main(String[] args) {
		DbUtil dbUtil = new DbUtil();
		try {
			dbUtil.getCon();
			System.out.println("连接成功");
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
}

	//com.microsoft.sqlserver.jdbc.SQLServerDriver
    //数据库驱动的名字（1.6 还是 1.8 之后就不需要了，这里还是加上吧）
	String driverName = "com.mysql.jdbc.Driver";
	//jdbc:sqlserver://127.0.0.1:1433;DatabaseName=demo
    //连接数据库的地址，这里要改的就是后面的 demo 换成你的数据库名字（我上面的是 demo）
	String dbURL = "jdbc:mysql://localhost:3306/demo";
    //你的数据库的帐号
	String userName = "root";
    //密码
	String userPwd = "admin"; 

import java.util.Date;

public class StuInfo {

	private Long stuId;
	private String stuName;
	private String stuSex;
	private Date stuDob;
	private String stuMajor;
	
	public Long getStuId() {
		return stuId;
	}

	public void setStuId(Long stuId) {
		this.stuId = stuId;
	}

	public String getStuName() {
		return stuName;
	}

	public void setStuName(String stuName) {
		this.stuName = stuName;
	}

	public String getStuSex() {
		return stuSex;
	}

	public void setStuSex(String stuSex) {
		this.stuSex = stuSex;
	}

	public Date getStuDob() {
		return stuDob;
	}

	public void setStuDob(Date stuDob) {
		this.stuDob = stuDob;
	}

	public String getStuMajor() {
		return stuMajor;
	}

	public void setStuMajor(String stuMajor) {
		this.stuMajor = stuMajor;
	}
	
	public StuInfo() {

	}

	public StuInfo(String stuName, String stuSex, Date stuDob, String stuMajor) {
		this.stuName = stuName;
		this.stuSex = stuSex;
		this.stuDob = stuDob;
		this.stuMajor = stuMajor;
	}
}

public class UserDao {
	public ResultSet getUsers(User user, Connection con) throws SQLException {
		StringBuffer sql = new StringBuffer("select * from t_user ");
		if (user.getUserName()!= null) {
			sql.append(" where userName like '%"+user.getUserName()+"%'");
		}
		PreparedStatement ps = con.prepareStatement(sql.toString());
		return ps.executeQuery();
	}
	
	public int delete(User user, Connection con) throws SQLException{
		String sql="delete from t_user where userName='"+user.getUserName()+"'";
		PreparedStatement ps = con.prepareStatement(sql);
		return ps.executeUpdate();
	}
	
	public int add(User user, Connection con) throws SQLException{
		String sql="insert into t_user  values(?,?)";
		PreparedStatement ps = con.prepareStatement(sql);
		ps.setString(1, user.getUserName());
		ps.setString(2, user.getTel());
		return ps.executeUpdate();
	}
	
	public int modify(User user, Connection con) throws SQLException{
		String sql="update t_user  set userName=?, tel=? where userName = '"+user.getUserName()+"'";
		PreparedStatement ps = con.prepareStatement(sql);
		ps.setString(1, user.getUserName());
		ps.setString(2, user.getTel());
		System.out.println(sql);
		return ps.executeUpdate();
	}
}