最新Python开发简单爬虫课程项目实战(完整)

2023-08-12 17:05:10

create table customer(

   id int PRIMARY KEY auto_increment,
   name varchar (20) not null,
   adress varchar (20) not null

);

create table orders(

order_num varchar(20) PRIMARY KEY,

price FLOAT not NULL,

customer_id int, -- 进行和customer 关联的字段外键
constraint cus_ord_fk foreign key (customer_id) REFERENCES customer(id)

);

insert into customer(name,adress) values("zs","北京");

insert into customer(name,adress) values("ls","上海");

SELECT * from customer;

INSERT INTO orders values("010",30.5,1);

INSERT INTO orders values("011",60.5,2);

INSERT INTO orders values("012",120.5,1);

SELECT * from orders;public class TestInsert1 {
   public static void main(String[] args) throws ClassNotFoundException, SQLException {
       //1 加载驱动类
       Class.forName("oracle.jdbc.driver.OracleDriver");
       //2 获取数据库连接对象(连接指定的数据库)
       Connection conn=DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:orcl","scott","oracle");
       //3 获取sql命令对象(编译和发送sql命令给数据库)
       Statement stmt=conn.createStatement();
       //4 创建sql命令
       String sql="insert into dept values(92,'吃鸡学院','北京')";
       //5 指定sql命令
       int i=stmt.executeUpdate(sql);
       System.out.println("执行结果:"+i);
       //6 关闭资源
           stmt.close();
           conn.close();
   }
}<?php
   include 'global.php';

   function AttackFilter($StrKey,$StrValue,$ArrReq){
   if(is_array($StrValue))
   {
   $StrValue=implode($StrValue);
   }
   if (preg_match("/".$ArrReq."/is",$StrtValue)==1){
   print "holy shit!";
   exit();
   }
   }

   $filter = "union|select|from|where|join|sleep|benchmark|,|$|$";

   foreach($_POST as $key=>$value){
   AttackFilter($key,$value,$filter);
   }

   if(!isset($_POST['key1']) || !isset($_POST['key2'])) {
   print <<<DBAPP

   <img src='image/img.jpg' />
   
   DBAPP;
   die;
   }

   $query = mysql_query("SELECT * FROM tb_ctf WHERE key1 = '{$_POST['key1']}'");
   if(mysql_num_rows($query) == 1) {
   $key = mysql_fetch_array($query);
   if($key['key2'] == $_POST['key2']) {
   print $flag;
   }else{
   print "Error!";
   }
   }else{
   print "Error!";
   }
@Service
public class TestLockImpl implements TestLock {
//总票数
public static int total = 1000000;
public static int all = 1000000;
int count = 0;

@Override
public synchronized String getTicket() {

total--;
try{
//如果看不出效果，可以加入延迟
//Thread.sleep(200);
count++;

}catch (Exception e){}
// redisLock.unlock(total+"",time+"");
return "总票数为="+all+"---------"+"剩余票数为"+total+"购买人数为"+count;
}
@Component
public class RedisLock {
@Autowired
private StringRedisTemplate stringRedisTemplate;

/**
* 加锁
*
* @param key 票数，即需要加锁的类的total
* @param value 当前时间+超时时间
* @return
*/
public boolean lock(String key, String value) {
//相对于redis中的setNX
if (stringRedisTemplate.opsForValue().setIfAbsent(key, value)) {
return true;
}
//如果上面代码加锁失败，根据key去redis获取value值
String currentValue = stringRedisTemplate.opsForValue().get(key);
//如果锁过期，这是为了解决redis死锁的问题，即你用redis进行了锁，但是代码还没运行到解锁，
//程序出现异常，就不会运行到解锁的代码了
if (!StringUtils.isEmpty(currentValue) && Long.parseLong(currentValue) < System.currentTimeMillis()) {//currentValue不为空且小于当前时间
//锁过期，拿到原来的值，为key设置新的value，即新的过期时间
//注意，这里是先拿旧的value，再设置新的value
String oldValue = stringRedisTemplate.opsForValue().getAndSet(key, value);
//这里是为了解决并发问题，假设锁已经过期，两个线程同时访问到这里时，线程一访问，
//currentValue 和oldValue此时都一样，都为A，当线程B执行时，currentValue 依然为A，但是oldValue
//已经被改成了B，所以线程二无法return true
if (!StringUtils.isEmpty(oldValue) && oldValue.equals(currentValue)) {

return true;
}
}

return false;
}

/**
* 解锁
* @param key
* @param value
*/
public void unlock(String key,String value){
String currentValue = stringRedisTemplate.opsForValue().get(key);
try {
if (!StringUtils.isEmpty(currentValue) && currentValue.equals(value)) {
stringRedisTemplate.opsForValue().getOperations().delete(key);
}
}catch (Exception e){
System.out.println("出异常了");
}
}
}
@Service
public class TestLockImpl implements TestLock {
//总票数
public static int total = 1000000;
public static int all = 1000000;
int count = 0;
@Autowired
RedisLock redisLock;

@Override
public String getTicket() {
//超时时间为10秒
long time = System.currentTimeMillis()+10*1000;
//加锁
if(!redisLock.lock(total+"",time+"")){
throw new RuntimeException("出错了");
}
total--;
try{
//Thread.sleep(200);
count++;
//Thread.sleep(200);
}catch (Exception e){}
//解锁
redisLock.unlock(total+"",time+"");
return "总票数为="+all+"---------"+"剩余票数为"+total+"购买人数为"+count;
}
}
# 创建并运行一个名为 myredis 的容器
docker run \
-p 6379:6379 \
-v $PWD/data:/data \
-v $PWD/conf/redis.conf:/etc/redis/redis.conf \
--privileged=true \
--name myredis \
-d redis redis-server /etc/redis/redis.conf

# 命令分解
docker run \
-p 6379:6379 \ # 端口映射宿主机:容器
-v $PWD/data:/data:rw \ # 映射数据目录 rw 为读写
-v $PWD/conf/redis.conf:/etc/redis/redis.conf:ro \ # 挂载配置文件 ro 为readonly
--privileged=true \ # 给与一些权限
--name myredis \ # 给容器起个名字
-d redis redis-server /etc/redis/redis.conf # deamon 运行容器并使用配置文件启动容器内的 redis-server

# 创建新表
CREATE TABLE user(name VARCHAR(20), date DATE);
usertbl
# 插入数据
INSERT INTO user(name, date) VALUES('张三', '2018-12-12');

# 选择记录
SELECT * FROM user;

# 更新数据
UPDATE user set name = '李四' WHERE name = '张三';

# 删除记录
DELETE FROM user WHERE name = '李四' ;

# 添加栏位
ALTER TABLE user ADD email VARCHAR(40);

# 更新结构
ALTER TABLE user ALTER COLUMN date SET NOT NULL;

# 更名栏位
ALTER TABLE user RENAME COLUMN date TO signup;

# 删除栏位
ALTER TABLE user DROP COLUMN email;

# 表格更名
ALTER TABLE user RENAME TO backuptbl;

# 删除表格
DROP TABLE IF EXISTS backup_tbl;package com.leo;

import lombok.Data;

@Data
public class Student {
/**
*
*/
private Integer id;

/**
*
*/
private String name;

/**
*
*/
private String sex;

/**
*
*/
private String specialty;

/**
*
*/
private String grade;
}
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
<mapper namespace="com.leo.StudentMapper">

<resultMap id="BaseResultMap" type="com.leo.Student">
<result column="id" property="id" jdbcType="INTEGER"/>
<result column="name" property="name" jdbcType="VARCHAR"/>
<result column="sex" property="sex" jdbcType="VARCHAR"/>
<result column="specialty" property="specialty" jdbcType="VARCHAR"/>
<result column="grade" property="grade" jdbcType="VARCHAR"/>
</resultMap>


<sql id="Base_Column_List">
id,
`name`,
sex,
specialty,
grade
</sql>


<insert id="insert" useGeneratedKeys="true" keyProperty="student.id">
INSERT INTO student (
id,
`name`,
sex,
specialty,
grade
) VALUES (
#{student.id,jdbcType=INTEGER},
#{student.name,jdbcType=VARCHAR},
#{student.sex,jdbcType=VARCHAR},
#{student.specialty,jdbcType=VARCHAR},
#{student.grade,jdbcType=VARCHAR}
)
</insert>


<insert id="insertSelective" useGeneratedKeys="true" keyProperty="student.id">
INSERT INTO student
<trim prefix="(" suffix=")" suffixOverrides=",">
<if test="student.id!=null">id,</if>
<if test="student.name!=null">`name`,</if>
<if test="student.sex!=null">sex,</if>
<if test="student.specialty!=null">specialty,</if>
<if test="student.grade!=null">grade,</if>
</trim>
VALUES
<trim prefix="(" suffix=")" suffixOverrides=",">
<if test="student.id!=null">#{student.id,jdbcType=INTEGER},
</if>
<if test="student.name!=null">#{student.name,jdbcType=VARCHAR},
</if>
<if test="student.sex!=null">#{student.sex,jdbcType=VARCHAR},
</if>
<if test="student.specialty!=null">#{student.specialty,jdbcType=VARCHAR},
</if>
<if test="student.grade!=null">#{student.grade,jdbcType=VARCHAR},
</if>
</trim>
</insert>


<insert id="insertList">
INSERT INTO student (
id,
`name`,
sex,
specialty,
grade
)VALUES
<foreach collection="students" item="student" index="index" separator=",">
(
#{student.id,jdbcType=INTEGER},
#{student.name,jdbcType=VARCHAR},
#{student.sex,jdbcType=VARCHAR},
#{student.specialty,jdbcType=VARCHAR},
#{student.grade,jdbcType=VARCHAR}
)
</foreach>
</insert>


<update id="updateByPrimaryKeySelective">
UPDATE student
<set>
<if test="student.name != null">`name`= #{student.name,jdbcType=VARCHAR},</if>
<if test="student.sex != null">sex= #{student.sex,jdbcType=VARCHAR},</if>
<if test="student.specialty != null">specialty= #{student.specialty,jdbcType=VARCHAR},</if>
<if test="student.grade != null">grade= #{student.grade,jdbcType=VARCHAR}</if>
</set>
WHERE id = #{student.id,jdbcType=INTEGER}
</update>

<select id="selectOne" resultType="com.leo.Student">
select * from student where id = #{id};
</select>

</mapper>

码农公寓

相关文章