java JDBC Statement使用方法

package com.nhfc99.login;

import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.ResultSet;

import java.sql.SQLException;

import java.sql.Statement;

//import javax.activation.DataSource;

import javax.naming.Context;

import javax.naming.InitialContext;

import javax.naming.NamingException;

import javax.sql.DataSource;

//import com.mysql.jdbc.Statement;

public class ConnectSql {

private Connectionconn = null;

public void connectMysql() throws ClassNotFoundException, SQLException {

// 基本的连接数据库方式

// Statementstmt = null;

// // 注册 JDBC 驱动器

// Class.forName("com.mysql.jdbc.Driver");

// // 打开一个连接

// conn =

// DriverManager.getConnection("jdbc:mysql://127.0.0.1:3306/mysql?characterEncoding=utf8&useSSL=true",

// "root", "nhfc99");

// if (conn == null) {

// System.out.println("连接失败");

// } else {

// System.out.println("连接成功");

// Stringsql = "SELECT * FROM user";

// stmt = (Statement) conn.createStatement();

// ResultSetrs = stmt.executeQuery(sql);

// while (rs.next()) {

// System.out.println("User = " + rs.getString("User") + "\n");

// System.out.println("Host = " + rs.getString("Host"));

// }

// }

// 使用数据库连接池进行获取数据库的连接

try {

Context context =new InitialContext();

Context envContext = (Context)context.lookup("java:comp/env");

DataSource ds = (DataSource)envContext.lookup("jdbc/mysqlds");

conn = ds.getConnection();

if (conn ==null) {

System.out.println("连接数据库失败\n");

} else {

System.out.println("连接数据库成功\n");

}

// 检索用户信息

Statement statement = (Statement)conn.createStatement();

ResultSet resultSet =statement.executeQuery("SELECT * FROM Users");

booleanisHaveNextValue = resultSet.next();

if (isHaveNextValue) {

do {

int id = resultSet.getInt("id");

String username =resultSet.getString("username");

int age = resultSet.getInt("age");

System.out.println("id = " +id + ", username = " +username + ", age = " +age);

isHaveNextValue =resultSet.next();

} while (isHaveNextValue);

}

//清除

statement.close();

//关闭数据库连接交回连接池

closeSqlConnection();

} catch (NamingExceptione) {

// TODO: handle exception

System.out.println("getExplanation = " +e.getMessage());

}

}

public void closeSqlConnection() {

try {

conn.close();

} catch (SQLExceptione) {

// TODO: handle exception

}

}

}