Merge branch 'yinshunyu' into dev

尹顺宇学习笔记/尹顺宇11.05作业/尹顺宇11.05学习笔记.md

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+# SpringBoot+Redis
+
+前瞻：
+
+Reids的Java客户端有
+
+1.Jedis  
+
+2.Lettuce  
+
+3.Spring Data Redis
+
+我们主要使用Spring Data Redis
+
+## 1.操作步骤：
+
+### 1.1 导入Spring Data Redis 的maven坐标
+
+```xml
+<dependency>
+    <groupId>org.springframework.boot</groupId>
+    <artifactId>spring-boot-starter-data-redis</artifactId>
+</dependency>
+```
+
+### 1.2 配置redis数据源
+
+```
+spring:
+  redis:
+    host: ${sky.redis.host}
+    port: ${sky.redis.port}
+    password: ${sky.redis.password}
+    database: ${sky.redis.database}
+```
+
+```yaml
+sky:
+  redis:
+    host: localhost
+    port: 6379
+    password:
+    database: 10
+```
+
+### 1.3 编写配置类，创建RedisTemplete对象
+
+```java
+@Configuration
+@Slf4j
+public class RedisConfiguration {
+    @Bean
+    public RedisTemplate redisTemplate(RedisConnectionFactory redisConnectionFactory){
+        log.info("创建RedisTemplate对象...");
+        RedisTemplate redisTemplate = new RedisTemplate();
+        //设置redis连接工厂对象
+        redisTemplate.setConnectionFactory(redisConnectionFactory);
+        //设置redis的key的序列化器
+        redisTemplate.setKeySerializer(new StringRedisSerializer());
+        return redisTemplate;
+    }
+}
+
+```
+
+![1762315033093](C:\Users\Administrator\AppData\Roaming\Typora\typora-user-images\1762315033093.png)
+
+加redis的key的序列化器之前：
+
+![1762315212677](C:\Users\Administrator\AppData\Roaming\Typora\typora-user-images\1762315212677.png)
+
+加redis的key的序列化器之后：
+
+![1762315247579](C:\Users\Administrator\AppData\Roaming\Typora\typora-user-images\1762315247579.png)
+
+### 1.4 通过Redis Template对象操作Redis
+
+```java
+@SpringBootTest
+public class SpringDataRedisTest {
+    @Autowired
+    private RedisTemplate redisTemplate;
+    @Test
+    public void testRedisTemplate(){
+        System.out.println(redisTemplate);
+        //操作字符串类型
+        ValueOperations valueOperations = redisTemplate.opsForValue();
+        HashOperations hashOperations = redisTemplate.opsForHash();
+        ListOperations listOperations = redisTemplate.opsForList();
+        SetOperations setOperations = redisTemplate.opsForSet();
+        ZSetOperations zSetOperations = redisTemplate.opsForZSet();
+    }
+    //String类型
+    @Test
+    public void testString(){
+        //set get setex setnx
+        redisTemplate.opsForValue().set("name","小明");
+        String  city = (String) redisTemplate.opsForValue().get("name");
+        System.out.println(city);
+        redisTemplate.opsForValue().set("code","1234",3, TimeUnit.MINUTES);
+        //setIfAbsent就是setnx
+        redisTemplate.opsForValue().setIfAbsent("lock","1");
+        redisTemplate.opsForValue().setIfAbsent("lock","2");
+    }
+    //Hash类型
+    @Test
+    public void testHash(){
+        //hset hget hdel hkeys hvals
+        HashOperations hashOperations = redisTemplate.opsForHash();
+        //hset
+        hashOperations.put("100","name","yinshunyu");
+        hashOperations.put("100","age","20");
+        //get
+        String name = (String) hashOperations.get("100", "name");
+        System.out.println(name);
+        //hkeys
+        Set keys = hashOperations.keys("100");
+        System.out.println(keys);
+        //hvals
+        List values = hashOperations.values("100");
+        System.out.println(values);
+        //hdel
+        hashOperations.delete("100","age");
+    }
+    //List类型
+    @Test
+    public void testList(){
+        //lpush  lrange rpop llen
+        ListOperations listOperations = redisTemplate.opsForList();
+        listOperations.leftPushAll("mylist","a","b","c");
+        listOperations.leftPush("mylist","d");
+        List mylist = listOperations.range("mylist", 0, -1);
+        System.out.println(mylist);
+        listOperations.rightPop("mylist");
+        Long size = listOperations.size("mylist");
+        System.out.println(size);
+    }
+    //Set类型
+    @Test
+    public void testSet(){
+        //sadd smembers scard sinter sunion srem
+        SetOperations setOperations = redisTemplate.opsForSet();
+        setOperations.add("set1","a","b","c","d");
+        setOperations.add("set2","a","b","x","y");
+        //smembers 获取元素
+        Set members = setOperations.members("set1");
+        System.out.println(members);
+        //scard 元素个数
+        Long size = setOperations.size("set1");
+        System.out.println(size);
+        //sinter 交集
+        Set intersect = setOperations.intersect("set1", "set2");
+        System.out.println(intersect);
+        //sunion 并集
+        Set union = setOperations.union("set1", "set2");
+        System.out.println( union);
+        setOperations.remove("set1","a","b");
+    }
+    //ZSet类型
+     @Test
+    public void testZset(){
+        //zadd zrange zincrby zrem
+        ZSetOperations zSetOperations = redisTemplate.opsForZSet();
+
+        zSetOperations.add("zset1","a",10);
+        zSetOperations.add("zset1","b",12);
+        zSetOperations.add("zset1","c",9);
+
+        Set zset1 = zSetOperations.range("zset1", 0, -1);
+        System.out.println(zset1);
+        //zincrby 修改分数
+        zSetOperations.incrementScore("zset1","c",10);
+
+        zSetOperations.remove("zset1","a","b");
+    }
+    
+}
+
+```
+
+![1762315160999](C:\Users\Administrator\AppData\Roaming\Typora\typora-user-images\1762315160999.png)
+
+## 2.缓存菜品模拟
+
+**修改用户端接口 DishController 的 list 方法，加入缓存处理逻辑：**
+
+```java
+	@Autowired
+    private RedisTemplate redisTemplate;
+	/**
+     * 根据分类id查询菜品
+     *
+     * @param categoryId
+     * @return
+     */
+    @GetMapping("/list")
+    @ApiOperation("根据分类id查询菜品")
+    public Result<List<DishVO>> list(Long categoryId) {
+
+        //构造redis中的key，规则：dish_分类id
+        String key = "dish_" + categoryId;
+
+        //查询redis中是否存在菜品数据
+        List<DishVO> list = (List<DishVO>) redisTemplate.opsForValue().get(key);
+        if(list != null && list.size() > 0){
+            //如果存在，直接返回，无须查询数据库
+            return Result.success(list);
+        }
+		////////////////////////////////////////////////////////
+        Dish dish = new Dish();
+        dish.setCategoryId(categoryId);
+        dish.setStatus(StatusConstant.ENABLE);//查询起售中的菜品
+
+        //如果不存在，查询数据库，将查询到的数据放入redis中
+        list = dishService.listWithFlavor(dish);
+        ////////////////////////////////////////////////////////
+        redisTemplate.opsForValue().set(key, list);
+
+        return Result.success(list);
+    }
+```
+
+**抽取清理缓存的方法：**
+
+在管理端DishController中添加
+
+```java
+	@Autowired
+    private RedisTemplate redisTemplate;
+	/**
+     * 清理缓存数据
+     * @param pattern
+     */
+    private void cleanCache(String pattern){
+        Set keys = redisTemplate.keys(pattern);
+        redisTemplate.delete(keys);
+    }
+```
+
+**调用清理缓存的方法，保证数据一致性：**
+
+**1). 新增菜品优化**
+
+```java
+	/**
+     * 新增菜品
+     *
+     * @param dishDTO
+     * @return
+     */
+    @PostMapping
+    @ApiOperation("新增菜品")
+    public Result save(@RequestBody DishDTO dishDTO) {
+        log.info("新增菜品：{}", dishDTO);
+        dishService.saveWithFlavor(dishDTO);
+
+        //清理缓存数据
+        String key = "dish_" + dishDTO.getCategoryId();
+        cleanCache(key);
+        return Result.success();
+    }
+```
+
+# EasyExcel初步理解
+
+## 依赖导入
+
+```
+
+ <!-- https://mvnrepository.com/artifact/com.alibaba/easyexcel -->
+        <dependency>
+            <groupId>com.alibaba</groupId>
+            <artifactId>easyexcel</artifactId>
+            <version>2.1.1</version>
+        </dependency>
+        <dependency>
+            <groupId>org.projectlombok</groupId>
+            <artifactId>lombok</artifactId>
+            <version>1.18.10</version>
+```
+
+### 创建与表格对应的实体类
+
+```
+ 
+@Data
+@AllArgsConstructor
+@NoArgsConstructor
+public class Student {
+ 
+    @ExcelProperty(value = "学生id")
+    private Integer id;
+    @ExcelProperty(value = "学生姓名")
+    private String name;
+ 
+    @ExcelProperty(value = "学生年龄")
+    private Integer age;
+}
+ 
+```
+
+## 写操作
+
+```
+ 
+public class WriteExcel {
+    public static void main(String[] args) {
+ 
+        //准备文件路径
+        String fileName="D:/destory/test/easyexcel.xls";
+        //写出文件
+        EasyExcel.write(fileName, Student.class).sheet("easyexcel")
+                .doWrite(data());
+    }
+ 
+ 
+    private static List<Student> data(){
+        ArrayList<Student> list = new ArrayList<>();
+        for (int i = 0; i < 10; i++) {
+            Student student = new Student(i, "董德" + 1, 22 + i);
+            list.add(student);
+        }
+        return  list;
+    }
+}
+```
+
+## 读操作
+
+### 改造实体类
+
+```
+ 
+@Data
+@AllArgsConstructor
+@NoArgsConstructor
+public class Student {
+ 
+    @ExcelProperty(value = "学生id",index = 0)
+    private Integer id;
+    @ExcelProperty(value = "学生姓名",index = 1)
+    private String name;
+ 
+    @ExcelProperty(value = "学生年龄",index = 2)
+    private Integer age;
+}
+ 
+```
+
+### 创建监听器
+
+```
+ 
+public class EasyExcelLinster extends AnalysisEventListener<Student> {
+ 
+  List<Student> list=  new ArrayList<Student>();
+    //一行一行的去读取里面的数据
+    @Override
+    public void invoke(Student student, AnalysisContext analysisContext) {
+        System.out.println(student);
+        list.add(student);
+    }
+ 
+    @Override
+    public void doAfterAllAnalysed(AnalysisContext analysisContext) {
+ 
+    }
+ 
+ 
+}
+ 
+```
+
+### 读取
+
+```
+ 
+public class ReadExcel {
+    public static void main(String[] args) {
+        //准备文件路径
+        String fileName="D:/destory/test/easyexcel.xls";
+        EasyExcel.read(fileName, Student.class, new ExcelListener()).sheet().doRead();
+    }
+}
+ 
+```
+