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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