JDBC

作者: 蓝色_fea0 | 来源:发表于2018-05-27 21:37 被阅读11次
    package com.wuhongyu.test1.jdbc;
    
    import java.sql.*;
    import java.util.ArrayList;
    import java.util.List;
    
    public class JDBC {
        private String url ="jdbc:mysql://localhost:3306/test";
        private String driver = "com.mysql.jdbc.Driver";
        private String name = "root";
        private String pwd = "root";
    
        public Connection getConnection() throws Exception {
            Class.forName(driver);
            Connection connection = DriverManager.getConnection(url, name, pwd);
            return connection;
        }
    
        public List<User>selectAll(){
            Connection connection = null;
            Statement statement = null;
            ResultSet resultSet = null;
            List<User> list = new ArrayList<>();
            try {
                connection = this.getConnection();
                statement = connection.createStatement();
                String sql = "select * from user";
                resultSet = statement.executeQuery(sql);
                while(resultSet.next()){
                    User user = new User();
                    user.setId(resultSet.getInt("id"));
                    user.setUsername(resultSet.getString("username"));
                    user.setPassword(resultSet.getString("password"));
                    list.add(user);
                }
            } catch (Exception e) {
                e.printStackTrace();
            }finally {
                if (resultSet!=null) {
                    try {
                        resultSet.close();
                        System.out.println("关闭r");
                    } catch (SQLException e) {
                        e.printStackTrace();
                    }finally {
                        if(statement !=null){
                            try {
                                statement.close();
                                System.out.println("关闭s");
                            } catch (SQLException e) {
                                e.printStackTrace();
                            }finally {
                                if(connection!=null){
                                    try {
                                        connection.close();
                                        System.out.println("关闭c");
                                    } catch (SQLException e) {
                                        e.printStackTrace();
                                    }
                                }
                            }
                        }
                    }
                }
    
            }
    
            return list;
        }
    
    
        public void add(User user){
            Connection connection = null;
            PreparedStatement ps = null;
            String sql = "insert into user values(?,?,?)";
            try {
                connection = this.getConnection();
                ps = connection.prepareStatement(sql);
                ps.setInt(1,user.getId());
                ps.setString(2,user.getUsername());
                ps.setString(3,user.getPassword());
                ps.executeUpdate();
            }catch (Exception e){
                e.printStackTrace();
            }finally {
                if(ps !=null) {
                    try {
                        ps.close();
                        System.out.println("关闭s");
                    } catch (SQLException e) {
                        e.printStackTrace();
                    } finally {
                        if (connection != null) {
                            try {
                                connection.close();
                                System.out.println("关闭c");
                            } catch (SQLException e) {
                                e.printStackTrace();
                            }
                        }
                    }
                }
            }
        }
    
    }
    

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