<?php
/*****************************
*数据库连接
*****************************/
$conn = @mysql_connect("localhost","root","123");
if (!$conn){
  die("连接数据库失败：" . mysql_error());
}
mysql_select_db("test", $conn);
//字符转换，读库
mysql_query("set character set utf8");
mysql_query("set names utf8");
?>

<?php 
  error_reporting(0);     //防止报错
  include('mysql.php');
  $result=mysql_query("select * from user"); //根据前面的计算出开始的记录和记录数
  // 循环取出记录
  $six;
  while($row=mysql_fetch_row($result))
  {  
  echo $row[0];
  echo $row[1];
  }
?>

package com.mysqltest;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
/*
 * **Mysql连接**
 * 
 * 参数：
 * conn 连接
 * url mysql数据库连接地址
 * user 数据库登陆账号
 * password 数据库登陆密码
 * 方法：
 * conn 获取连接
 */
public class MySQLConnection {
  public static Connection conn = null;
  public static String driver = "com.mysql.jdbc.Driver";
  public static String url = "jdbc:mysql://127.0.0.1:3306/post";
  public static String user = "root";
  public static String password = "123";
  /*
   * 创建Mysql数据连接 第一步：加载驱动 Class.forName（Driver） 第二步：创建连接
   * DriverManager.getConnection(url, user, password);
   */
  public Connection conn() {
    try {
      Class.forName(driver);
    } catch (ClassNotFoundException e) {
      System.out.println("驱动加载错误");
      e.printStackTrace();
    }
    try {
      conn = DriverManager.getConnection(url, user, password);
    } catch (SQLException e) {
      System.out.println("数据库链接错误");
      e.printStackTrace();
    }
    return conn;
  }
}

package com.mysqltest;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
/*
 * mysql增删改查
 */
public class Work {
  /*
   * insert 增加
   */
  public static int insert() {
    MySQLConnection connection = new MySQLConnection();
    Connection conns; // 获取连接
    PreparedStatement pst; // 执行Sql语句
    int i = 0;
    String sql = "insert into user (username,password) values(?,?)";
    try {
      conns = connection.conn();
      pst = conns.prepareStatement(sql);
      pst.setString(1, "lizi");
      pst.setString(2, "123");
      i = pst.executeUpdate();
      pst.close();
      conns.close();
    } catch (SQLException e) {
      System.out.println("数据写入失败");
      e.printStackTrace();
    }
    return i;
  }
  /*
   * select 写入
   */
  public static void select() {
    MySQLConnection connection = new MySQLConnection();
    Connection conns; // 获取连接
    PreparedStatement pst; // 执行Sql语句(Statement)
    ResultSet rs; // 获取返回结果
    String sql = "select * from user";
    try {
      conns = connection.conn();
      pst = conns.prepareStatement(sql);
      rs = pst.executeQuery(sql);// 执行sql语句
      System.out.println("---------------------------------------");
      System.out.println("名字    |    密码");
      while (rs.next()) {
        System.out.println(rs.getString("username") + "    |    " + rs.getString("password"));
      }
      System.out.println("---------------------------------------");
      conns.close();
      pst.close();
      rs.close();
    } catch (SQLException e) {
      System.out.println("数据查询失败");
      e.printStackTrace();
    }
  }
  /*
   * update 修改
   */
  public static int update() {
    MySQLConnection connection = new MySQLConnection();
    Connection conns; // 获取连接
    PreparedStatement pst; // 执行Sql语句(Statement)
    int i = 0;
    String sql = "update user set password = ? where username = ?";
    try {
      conns = connection.conn();
      pst = conns.prepareStatement(sql);
      pst.setString(1, "123");
      pst.setString(2, "lizi");
      i = pst.executeUpdate();
      pst.close();
      conns.close();
    } catch (SQLException e) {
      System.out.println("数据修改失败");
      e.printStackTrace();
    }
    return i;
  }
  /*
   * delete 删除
   */
  public static int delete() {
    MySQLConnection connection = new MySQLConnection();
    Connection conns; // 获取连接
    PreparedStatement pst; // 执行Sql语句(Statement)
    int i = 0;
    String sql = "delete from user where username = ?";
    try {
      conns = connection.conn();
      pst = conns.prepareStatement(sql);
      pst.setString(1, "lizi");
      i = pst.executeUpdate();
      pst.close();
      conns.close();
    } catch (SQLException e) {
      System.out.println("数据删除失败");
      e.printStackTrace();
    }
    return i;
  }
  /*
   * test
   */
  public static void main(String[] args) {
    // System.out.println(insert());
     select();
    // System.out.println(update());
    // System.out.println(delete());
  }
}

<?php
 $conn=@mysql_connect("localhost","root","")or die("数据库连接错误");//链接数据库服务器
 mysql_select_db("messageboard",$conn);//选择数据库名为messageboard
 mysql_query("set names 'utf'");//使用utf编码，这里不能写成utf-否则将显示乱码，但UTF不区分大小写
 ?>

<>$sql=mysql_query("select * from tb_book");
$info=mysql_fetch_object($sql);
<>$sql=mysql_query("select * from tb_book where bookname like '%".trim($txt_book)."%'")；
$info=mysql_fetch_object($sql);

<>$sql=mysql_query("select * from tb_book");
$info=mysql_fetch_object($sql);
<>$sql=mysql_query("select * from tb_book where bookname like '%".trim($txt_book)."%'");
$info=mysql_fetch_object($sql);

<>$sql=mysql_query("select * from tb_book");
$row=mysql_fetch_row($sql);
<>$sql=mysql_query("select * from tb_book where bookname like '%".trim($txt_book)."%'");
$row=mysql_fetch_row($sql);

$sql=mysql_query("select * from tb_book");
......
<?php $nums=mysql_num_rows($sql);echo $nums;?>