package JDBCdemo;public class User {private long id;private String username;private String password;private int sex;private String addr;private String tel;private String idNumber;public User() {super();// TODO Auto-generated constructor stub
    }public User(long id, String username, String password, int sex, String addr, String tel, String idNumber) {super();this.id = id;this.username = username;this.password = password;this.sex = sex;this.addr = addr;this.tel = tel;this.idNumber = idNumber;}public long getId() {return id;}public void setId(long id) {this.id = id;}public String getUsername() {return username;}public void setUsername(String username) {this.username = username;}public String getPassword() {return password;}public void setPassword(String password) {this.password = password;}public int getSex() {return sex;}public void setSex(int sex) {this.sex = sex;}public String getAddr() {return addr;}public void setAddr(String addr) {this.addr = addr;}public String getTel() {return tel;}public void setTel(String tel) {this.tel = tel;}public String getIdNumber() {return idNumber;}public void setIdNumber(String idNumber) {this.idNumber = idNumber;}@Overridepublic String toString() {return "User [id=" + id + ", username=" + username + ", password=" + password + ", sex=" + sex + ", addr="+ addr + ", tel=" + tel + ", idNumber=" + idNumber + "]";}}

package JDBCdemo;import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;import JDBC.ConnectionFactory;public class UserJDBC {public static void main(String[] args) throws ClassNotFoundException, SQLException{UserJDBC u = new UserJDBC();    /*try {List<User> list = u.queryUsers();for (User user : list) {System.out.println(user);}} catch (ClassNotFoundException | SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}*//*try {System.out.println(u.updateUser(10,"aaa"));} catch (ClassNotFoundException | SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}*//*User user = new User(0,"小白","222",0, "上海", "182", "128");        int rows = u.addUser(user);System.out.println(rows);*/User user = u.queryUser("小白");        System.out.println(user);}//定义一个方法，查询全部用户public List<User> queryUsers() throws ClassNotFoundException, SQLException{//注册数据库驱动Class.forName("oracle.jdbc.driver.OracleDriver");//建立与数据库的链接Connection conn = DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:XE","easybuy","easybuy");//创建可执行SQL语句的StatementStatement stmt = conn.createStatement();//执行sql语句String sql = "select id,username,password,sex,id_number,tel,addr from t_user";//增删改：executeUpdate(String sql) 返回影响的行数，整型//查询：executeQuery(String sql) 返回一个结果集对象，resultSetResultSet rs = stmt.executeQuery(sql);//处理结果集List<User> list = new ArrayList<>();while(rs.next()){User user = new User(rs.getLong(1),rs.getString(2),rs.getString(3),rs.getInt(4),rs.getString(5),rs.getString(6),rs.getString(7));list.add(user);}//关闭资源
        ConnectionFactory.close(rs, stmt, conn);return list;}//通过id修改密码public int updateUser(long id,String password) throws ClassNotFoundException, SQLException{User user = new User();//注册驱动Class.forName("oracle.jdbc.driver.OracleDriver");//建立数据库链接Connection conn = DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:XE","easybuy","easybuy");//创建可执行的statement()/*Statement stmt = conn.createStatement();String sql = "update t_user set password= '"+ password +"'where id="+id;//执行sql语句int rows = stmt.executeUpdate(sql);*///使用prepareStatement()方法修改指定用户的密码String sql = "update t_user set password=? where id=?";PreparedStatement prep = conn.prepareStatement(sql);prep.setString(1,password);prep.setLong(2, id);int row = prep.executeUpdate();//释放资源if(conn!=null){conn.close();}/*if(stmt!=null){stmt.close();}*///return rows;if(prep!=null){prep.close();}return row;}//添加用户public int addUser(User user) throws ClassNotFoundException, SQLException{//注册驱动Class.forName("oracle.jdbc.driver.OracleDriver");//建立数据库链接Connection conn = DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:XE","easybuy","easybuy");//创建可执行的sql语句的prepareStatement()String sql = "insert into t_user(id,username,password,sex,addr,tel,id_number) "+ "values (t_user_id_seq.nextval,?,?,?,?,?,?)";//执行sql语句//设置占位符的值,第几个？下标就是几,从左到右,一个不能多,一个不能少PreparedStatement pstmt = conn.prepareStatement(sql);pstmt.setString(1,user.getUsername());pstmt.setString(2, user.getPassword());pstmt.setInt(3, user.getSex());pstmt.setString(4, user.getAddr());pstmt.setString(5, user.getTel());pstmt.setString(6, user.getIdNumber());//创建可执行的sql语句int rows = pstmt.executeUpdate();//关闭资源
        ConnectionFactory.close(pstmt, conn);return rows;}//通过用户名查找用户，使用PreparedStatement()完成public User queryUser(String username) throws ClassNotFoundException, SQLException{/*//注册驱动Class.forName("oracle.jdbc.driver.OracleDriver");//与数据库建立链接Connection conn = DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:XE", "easybuy", "easybuy");*/Connection conn = ConnectionFactory.getConnection();//创建可执行的sql语句String sql = "select id,username,password,sex,id_number,tel,addr from t_user where username=?";PreparedStatement s = conn.prepareStatement(sql);s.setString(1, username);ResultSet rs = s.executeQuery();User user = null;if(rs.next()){user = new User(rs.getLong(1),rs.getString(2),rs.getString(3),rs.getInt(4),rs.getString(5),rs.getString(6),rs.getString(7));    }ConnectionFactory.close(rs, s, conn);return user;}}