SpringBoot--中间件技术-2：整合redis，redis实战小案例，springboot cache，cache简化redis的实现，含代码

SpringBoot整合Redis

实现步骤

1. 导pom文件坐标

   <!--redis依赖-->
   <dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-data-redis</artifactId>
   </dependency>
   

2. yaml主配置文件，配置redis端口号

   spring:redis:host: localhostport: 6379
   

3. 测试类

   字符串专用类：StringRedisTemplate stringRedisTemplate

   @Autowired
   public RedisTemplate redisTemplate;
   @Test
   public void stringTest(){// 各种类型支持stringRedisTemplate.opsForValue();stringRedisTemplate.opsForList();stringRedisTemplate.opsForSet();stringRedisTemplate.opsForHash();stringRedisTemplate.opsForZSet();// 字符串stringRedisTemplate.opsForValue().set("teacher","刘老板");String teacher = stringRedisTemplate.opsForValue().get("teacher");System.out.println("stringRedisTemplate输出结果"+teacher);// 操作list列表stringRedisTemplate.opsForList().leftPush("tang","李白");stringRedisTemplate.opsForList().leftPush("tang","杜甫");stringRedisTemplate.opsForList().leftPushAll("songAll","欧阳修","苏轼","苏辙");List<String> songAll = stringRedisTemplate.opsForList().range("songAll", 0, 2);songAll.forEach(System.out::println);}
   

   对象专用类：RedisTemplate redisTemplate

   @Autowired(required = false)
   public RedisTemplate redisTemplate;
   @Test
   public void redisTemplate(){// 各种类型支持redisTemplate.opsForValue();redisTemplate.opsForList();redisTemplate.opsForSet();redisTemplate.opsForHash();redisTemplate.opsForZSet();ValueOperations valueOperations = redisTemplate.opsForValue();valueOperations.set("panda","花花");String panda = (String) valueOperations.get("panda");System.out.println(panda);Student student = new Student(1,"惠晨怡","女");redisTemplate.opsForValue().set("stu",student);Student student1 = (Student) redisTemplate.opsForValue().get("stu");System.out.println(student1);redisTemplate.opsForList().leftPushAll("animal","狗","猫","龙","鼠");List animal = redisTemplate.opsForList().range("animal", 0, 3);animal.forEach(System.out::println);}
   

   在可视化页面中查看对象存入的键和值，看不明白，没有可读性，可以使用自定义类

   自定义类实现步骤：

   pom文件导入fastJson

   <!--fastjson工具包 -->
   <dependency><groupId>com.alibaba</groupId><artifactId>fastjson</artifactId><version>1.2.3</version>
   </dependency><dependency><groupId>com.colobu</groupId><artifactId>fastjson-jaxrs-json-provider</artifactId><version>0.3.1</version>
   </dependency>
   

   添加配置类RedisConfig

   @Configuration
   public class RedisConfig {@Beanpublic RedisTemplate<Object,Object> jsonRedisTemplate(RedisConnectionFactory redisConnectionFactory) throws UnknownHostException {// 创建自定义模板RedisTemplate<Object, Object> template = new RedisTemplate<>();//配置json类型的序列化工具template.setKeySerializer(new StringRedisSerializer());template.setDefaultSerializer(new Jackson2JsonRedisSerializer<Object>(Object.class));
   template.setConnectionFactory(redisConnectionFactory);return template;}
   }
   

   测试：装配的redis模板类需要和自定义的同名

   @Autowired
   public RedisTemplate jsonRedisTemplate;
   @Test
   public void test03(){jsonRedisTemplate.opsForValue();jsonRedisTemplate.opsForList();jsonRedisTemplate.opsForSet();jsonRedisTemplate.opsForHash();jsonRedisTemplate.opsForZSet();Student student1 = new Student(2,"惠晨怡","男");Student student2 = new Student(3,"尚恒通","男");Student student3 = new Student(4,"李竟坡","男");ArrayList<Student> students = new ArrayList<>(Arrays.asList(student1,student2,student3));jsonRedisTemplate.opsForValue().set("stus",students);Object stus = jsonRedisTemplate.opsForValue().get("stus");String s = JSON.toJSONString(stus);List<Student> list = JSONObject.parseArray(s, Student.class);list.forEach(System.out::println);
   }
   

SpringBoot整合Redis实战案例

redis在项目中起到缓存作用，案例演示redis在项目中的实现

1. 导入pom.xml文件

   springboot版本2.7.14

   <dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId>
   </dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-test</artifactId><scope>test</scope>
   </dependency><!--mysql-->
   <dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>8.0.29</version>
   </dependency><!--mybatis-->
   <dependency><groupId>org.mybatis.spring.boot</groupId><artifactId>mybatis-spring-boot-starter</artifactId><version>2.0.1</version>
   </dependency><!--redis-->
   <dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-data-redis</artifactId>
   </dependency>
   

2. yaml配置文件配置数据源和redis

   # 配置数据源
   spring:datasource:driver-class-name: com.mysql.cj.jdbc.Driverurl: jdbc:mysql://localhost:3306/spring?serverTimezone=GMTusername: rootpassword: 123456# 配置redisredis:host: localhostport: 6379mybatis:configuration:map-underscore-to-camel-case: true
   

   用到了mybatis，所以配置了一个自动驼峰映射

3. Redis自定义模板配置类

   @Component
   public class RedisConfig {@Beanpublic RedisTemplate<Object,Object> jsonRedisTemplate(RedisConnectionFactory redisConnectionFactory) throws UnknownHostException {RedisTemplate<Object, Object> template = new RedisTemplate<>();template.setKeySerializer(new StringRedisSerializer());template.setDefaultSerializer(new Jackson2JsonRedisSerializer<Object>(Object.class));template.setConnectionFactory(redisConnectionFactory);return template;}
   }
   

4. 导入redisUtil工具类，工具栏中封装了大量redis操作代码，一般真实开发环境中都可以看到一个公司自己封装的RedisUtil

   @Component
   public  class RedisUtil {@Autowired(required = false)private RedisTemplate jsonRedisTemplate;// =========================================================/*** 指定缓存失效时间* @param key  键* @param time 时间(秒)*/public boolean expire(String key, long time) {try {if (time > 0) {jsonRedisTemplate.expire(key, time, TimeUnit.SECONDS);}return true;} catch (Exception e) {e.printStackTrace();return false;}}/*** 根据key 获取过期时间* @param key 键 不能为null* @return 时间(秒) 返回0代表为永久有效*/public long getExpire(String key) {return jsonRedisTemplate.getExpire(key, TimeUnit.SECONDS);}/*** 判断key是否存在* @param key 键* @return true 存在 false不存在*/public boolean hasKey(String key) {try {return jsonRedisTemplate.hasKey(key);} catch (Exception e) {return false;}}/*** 删除缓存* @param key 可以传一个值 或多个*/@SuppressWarnings("unchecked")public void del(String... key) {if (key != null && key.length > 0) {if (key.length == 1) {jsonRedisTemplate.delete(key[0]);} else {jsonRedisTemplate.delete(CollectionUtils.arrayToList(key));}}}// ============================String=============================/*** 普通缓存获取* @param key 键* @return 值*/public Object get(String key) {return key == null ? null : jsonRedisTemplate.opsForValue().get(key);}/*** 普通缓存放入* @param key   键* @param value 值* @return true成功 false失败*/public boolean set(String key, Object value) {try {jsonRedisTemplate.opsForValue().set(key, value);return true;} catch (Exception e) {return false;}}/*** 普通缓存放入并设置时间* @param key   键* @param value 值* @param time  时间(秒) time要大于0 如果time小于等于0 将设置无限期* @return true成功 false 失败*/public boolean set(String key, Object value, long time) {try {if (time > 0) {jsonRedisTemplate.opsForValue().set(key, value, time, TimeUnit.SECONDS);} else {set(key, value);}return true;} catch (Exception e) {e.printStackTrace();return false;}}/*** 递增* @param key   键* @param delta 要增加几(大于0)*/public long incr(String key, long delta) {if (delta < 0) {throw new RuntimeException("递增因子必须大于0");}return jsonRedisTemplate.opsForValue().increment(key, delta);}/*** 递减* @param key   键* @param delta 要减少几(小于0)*/public long decr(String key, long delta) {if (delta < 0) {throw new RuntimeException("递减因子必须大于0");}return jsonRedisTemplate.opsForValue().increment(key, -delta);}// ================================Map=================================/*** HashGet* @param key  键 不能为null* @param item 项 不能为null*/public Object hget(String key, String item) {return jsonRedisTemplate.opsForHash().get(key, item);}/*** 获取hashKey对应的所有键值* @param key 键* @return 对应的多个键值*/public Map<Object, Object> hmget(String key) {return jsonRedisTemplate.opsForHash().entries(key);}/*** HashSet* @param key 键* @param map 对应多个键值*/public boolean hmset(String key, Map<String, Object> map) {try {jsonRedisTemplate.opsForHash().putAll(key, map);return true;} catch (Exception e) {e.printStackTrace();return false;}}/*** HashSet 并设置时间* @param key  键* @param map  对应多个键值* @param time 时间(秒)* @return true成功 false失败*/public boolean hmset(String key, Map<String, Object> map, long time) {try {jsonRedisTemplate.opsForHash().putAll(key, map);if (time > 0) {expire(key, time);}return true;} catch (Exception e) {e.printStackTrace();return false;}}/*** 向一张hash表中放入数据,如果不存在将创建** @param key   键* @param item  项* @param value 值* @return true 成功 false失败*/public boolean hset(String key, String item, Object value) {try {jsonRedisTemplate.opsForHash().put(key, item, value);return true;} catch (Exception e) {e.printStackTrace();return false;}}/*** 向一张hash表中放入数据,如果不存在将创建** @param key   键* @param item  项* @param value 值* @param time  时间(秒) 注意:如果已存在的hash表有时间,这里将会替换原有的时间* @return true 成功 false失败*/public boolean hset(String key, String item, Object value, long time) {try {jsonRedisTemplate.opsForHash().put(key, item, value);if (time > 0) {expire(key, time);}return true;} catch (Exception e) {e.printStackTrace();return false;}}/*** 删除hash表中的值** @param key  键 不能为null* @param item 项 可以使多个 不能为null*/public void hdel(String key, Object... item) {jsonRedisTemplate.opsForHash().delete(key, item);}/*** 判断hash表中是否有该项的值** @param key  键 不能为null* @param item 项 不能为null* @return true 存在 false不存在*/public boolean hHasKey(String key, String item) {return jsonRedisTemplate.opsForHash().hasKey(key, item);}/*** hash递增 如果不存在,就会创建一个 并把新增后的值返回** @param key  键* @param item 项* @param by   要增加几(大于0)*/public double hincr(String key, String item, double by) {return jsonRedisTemplate.opsForHash().increment(key, item, by);}/*** hash递减** @param key  键* @param item 项* @param by   要减少记(小于0)*/public double hdecr(String key, String item, double by) {return jsonRedisTemplate.opsForHash().increment(key, item, -by);}// ============================set=============================/*** 根据key获取Set中的所有值* @param key 键*/public Set<Object> sGet(String key) {try {return jsonRedisTemplate.opsForSet().members(key);} catch (Exception e) {e.printStackTrace();return null;}}/*** 根据value从一个set中查询,是否存在** @param key   键* @param value 值* @return true 存在 false不存在*/public boolean sHasKey(String key, Object value) {try {return jsonRedisTemplate.opsForSet().isMember(key, value);} catch (Exception e) {e.printStackTrace();return false;}}/*** 将数据放入set缓存** @param key    键* @param values 值 可以是多个* @return 成功个数*/public long sSet(String key, Object... values) {try {return jsonRedisTemplate.opsForSet().add(key, values);} catch (Exception e) {e.printStackTrace();return 0;}}/*** 将set数据放入缓存** @param key    键* @param time   时间(秒)* @param values 值 可以是多个* @return 成功个数*/public long sSetAndTime(String key, long time, Object... values) {try {Long count = jsonRedisTemplate.opsForSet().add(key, values);if (time > 0)expire(key, time);return count;} catch (Exception e) {e.printStackTrace();return 0;}}/*** 获取set缓存的长度** @param key 键*/public long sGetSetSize(String key) {try {return jsonRedisTemplate.opsForSet().size(key);} catch (Exception e) {e.printStackTrace();return 0;}}/*** 移除值为value的** @param key    键* @param values 值 可以是多个* @return 移除的个数*/public long setRemove(String key, Object... values) {try {Long count = jsonRedisTemplate.opsForSet().remove(key, values);return count;} catch (Exception e) {e.printStackTrace();return 0;}}// ===============================list=================================/*** 获取list缓存的内容** @param key   键* @param start 开始* @param end   结束 0 到 -1代表所有值*/public List<Object> lGet(String key, long start, long end) {try {return jsonRedisTemplate.opsForList().range(key, start, end);} catch (Exception e) {e.printStackTrace();return null;}}/*** 获取list缓存的长度** @param key 键*/public long lGetListSize(String key) {try {return jsonRedisTemplate.opsForList().size(key);} catch (Exception e) {e.printStackTrace();return 0;}}/*** 通过索引 获取list中的值** @param key   键* @param index 索引 index>=0时， 0 表头，1 第二个元素，依次类推；index<0时，-1，表尾，-2倒数第二个元素，依次类推*/public Object lGetIndex(String key, long index) {try {return jsonRedisTemplate.opsForList().index(key, index);} catch (Exception e) {e.printStackTrace();return null;}}/*** 将list放入缓存** @param key   键* @param value 值*/public boolean lSet(String key, Object value) {try {jsonRedisTemplate.opsForList().rightPush(key, value);return true;} catch (Exception e) {e.printStackTrace();return false;}}/*** 将list放入缓存* @param key   键* @param value 值* @param time  时间(秒)*/public boolean lSet(String key, Object value, long time) {try {jsonRedisTemplate.opsForList().rightPush(key, value);if (time > 0)expire(key, time);return true;} catch (Exception e) {e.printStackTrace();return false;}}/*** 将list放入缓存** @param key   键* @param value 值* @return*/public boolean lSet(String key, List<Object> value) {try {jsonRedisTemplate.opsForList().rightPushAll(key, value);return true;} catch (Exception e) {e.printStackTrace();return false;}}/*** 将list放入缓存** @param key   键* @param value 值* @param time  时间(秒)* @return*/public boolean lSet(String key, List<Object> value, long time) {try {jsonRedisTemplate.opsForList().rightPushAll(key, value);if (time > 0)expire(key, time);return true;} catch (Exception e) {e.printStackTrace();return false;}}/*** 根据索引修改list中的某条数据** @param key   键* @param index 索引* @param value 值* @return*/public boolean lUpdateIndex(String key, long index, Object value) {try {jsonRedisTemplate.opsForList().set(key, index, value);return true;} catch (Exception e) {e.printStackTrace();return false;}}/*** 移除N个值为value** @param key   键* @param count 移除多少个* @param value 值* @return 移除的个数*/public long lRemove(String key, long count, Object value) {try {Long remove = jsonRedisTemplate.opsForList().remove(key, count, value);return remove;} catch (Exception e) {e.printStackTrace();return 0;}}}
   

5. 实体类POJO

   public class Student {private int stuId;private String stuName;private String stuSex;// get,set,构造，toString等
   }
   

6. Dao层：Mapper

   @Mapper
   public interface StudentMapper {@Delete("delete from student where stu_id = #{id}")public int delete(Integer id);@Select("select * from student where stu_id = #{id}")public Student find(Integer id);
   }
   

7. 业务层：

   接口

   public interface IStudentService {public void delete(int id);public Student find(int id);}
   

   实现类

   @Service
   public class StudentServiceImp implements IStudentService {@Autowired(required = false)private StudentMapper mapper;@Autowiredprivate RedisUtil redisUtil;// 删除用户策略：删除数据表中数据，然后删除缓存@Overridepublic void delete(int id) {// 删除数据库int res = mapper.delete(id);String key = "student:id:"+id;// 判断数据库是否删除成功if(res != 0){boolean hasKey = redisUtil.hasKey(key);if(hasKey){redisUtil.del(key);System.out.println("删除了缓存中的key:" + key);}}}// 获取用户策略：先从缓存中获取用户，没有则取数据表中数据，再将数据写入缓存@Overridepublic Student find(int id) {String key = "student:id:" + id;//1.1判断key在redis中是否存在boolean hasKey = redisUtil.hasKey(key);if (hasKey) {//1.2存在缓存则直接获取Object stu = redisUtil.get(key);ObjectMapper change = new ObjectMapper();Student student =   change.convertValue(stu,Student.class);System.out.println("==========从缓存中获得数据=========");System.out.println(student.getStuName());System.out.println("==============================");return student;} else {//1.3不存在缓存，先从数据库中获取，在保存至redis，最后返回用户Student student = mapper.find(id);System.out.println("==========从数据表中获得数据=========");System.out.println(student.getStuName());System.out.println("==============================");if (student != null){redisUtil.set(key, student);//写入缓存}return student;}}
   }
   

8. 控制器

   @RestController
   public class StudentController {@AutowiredIStudentService service;@RequestMapping("/delete/{id}")public Integer delete(@PathVariable("id") int id){service.delete(id);return id;}@RequestMapping("/find/{id}")public Student find(@PathVariable("id") int id){Student student = service.find(id);return student;}}
   

9. 启动服务，地址栏中测试查看控制台打印结果，（测试时一定要保证redis服务正在运行，否则存不进redis）

   第一次访问localhost:8080/find/1显示从数据表中获得的数据，第二次访问显示缓存中获取的数据

   

SpringBoot Cache

SpringBoot Cache介绍

Spring Cache是一个框架， 实现了基于注解的缓存功能，只需要简单地加一个注解，就能实现缓存功能。

Spring Cache提供了一层抽象，底层可以切换不同的cache实现。具体就是通过CacheManager接口来统一不同的缓存技术。

CacheManager缓存管理器是Spring提供的各种缓存技术抽象接口

针对不同的缓存技术需要实现不同的CacheManager：

CacheManager	描述
EhCacheCacheManager	使用EhCache作为缓存技术（Spring Cache框架操作的默认缓存）
GuavaCacheManager	使用Google的GuavaCache作为缓存技术
RedisCacheManager	使用Redis作为缓存技术

SpringBoot Cache常用注解

注解	说明
@EnableCaching	开启缓存注解功能
@Cacheable	在方法执行前spring先查看缓存中是否有数据，如果有数据，则直接返回缓存数据;若没有数据，调用方法并将方法返回值放到缓存中
@CachePut	将方法的返回值放到缓存中
@CacheEvict	将一条或多条数据从缓存中删除

使用步骤：

1. 引入缓存启动器：spring-boot-starter-cache，spring-boot-starter-data-redis

2. @EnableCaching：在启动类上，开启基于注解的缓存

3. @Cacheable : 标在方法上，返回的结果会进行缓存

属性: value/cacheNames缓存的名字

​ key : 作为缓存中的Key值，可自已使用 SpEL表达式指定(不指定就是参数值)， 缓存结果是

​ 方法返回值

名字	描述	示例
methodName	当前被调用的方法名	#root.methodName
target	当前被调用的目标对象	#root.target
targetClass	当前被调用的目标对象类	#root.targetClass
args	当前被调用的方法的参数列表	#root.args[0]
caches	当前方法调用使用的缓存列表（如@Cacheable(value={“cache1”,“cache2”})），则有两个cache	#root.caches[0].name
argument name	方法参数的名字. 可以直接 #参数名 ，也可以使用 #p0或#a0 的形式，0代表参数的索引；	#iban 、 #a0 、 #p0
result	方法执行后的返回值（仅当方法执行之后的判断有效,在@CachePut 使用于更新数据后可用）	#result

SpringBoot Cache案例简化Redis

代码实现演示：

1. pom文件导坐标

   <!--redis依赖-->
   <dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-data-redis</artifactId>
   </dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-cache</artifactId>
   </dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId>
   </dependency>
   <dependency><groupId>org.mybatis.spring.boot</groupId><artifactId>mybatis-spring-boot-starter</artifactId><version>2.0.1</version>
   </dependency><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><scope>runtime</scope>
   </dependency>
   <dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-test</artifactId><scope>test</scope>
   </dependency>
   

2. yaml或properties主配置文件

   spring.datasource.username=root
   spring.datasource.password=123456
   spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
   spring.datasource.url=jdbc:mysql://localhost:3306/spring?serverTimezone=GMT%2B8#开启日志管理，可以查看sql语句
   logging.level.com.apesource.springboot_redis03.mapper=debug
   debug=true#配置要连接redis的地址
   spring.redis.host=localhost
   spring.redis.port=6379
   

3. POJO实体类

   根据要操作的表写，演示为student

   public class Student implements Serializable{private Integer stuId;private String stuName;private String stuSex;// get、set、toString、有参、无参构造
   }
   

4. Dao层StudentMapper

   public interface StudentMapper {@Select("select * from Student where stu_id = #{id}")public Student getStudentById(Integer id);@Delete("delete from student where stu_id = #{id}")public int deleteStudentById(Integer id);@Update("update student  set stu_name=#{stuName},stu_sex=#{stuSex} where stu_id = #{stuId}")public int updateById(Student student);}
   

5. Service层

   演示Cache简化redis实现，业务直接写实现类，没写接口

   @Service
   public class StudentService {@Autowired(required = false)StudentMapper mapper;//根据@Cacheable注解中的cacheNames+key拼接后的值为key@Cacheable(cacheNames = "students",key = "#id")public Student findById(Integer id){return mapper.getStudentById(id);}@CacheEvict(cacheNames = "students",key = "#id")public void deleteStudentById(Integer id){mapper.deleteStudentById(id);}@CachePut(cacheNames = "students",key = "#result.stuId")public Student updateById(Student student){mapper.updateById(student);return student;}}
   

   在业务层的方法中，加SpringBoot Cache的注解：

   cacheNames会在缓存中开辟一块儿叫"students"的空间，以键值对的形式存放数据，键是cacheNames+key拼接组成，value就是被标注注解的方法返回值

6. 控制器StudentController

   @RestController
   public class UserController {@AutowiredStudentService userService;@GetMapping("/findById/{id}")public Student findById(@PathVariable("id") Integer id) {Student stu = userService.findById(id);return stu;}@GetMapping("/delete/{id}")public Integer delete(@PathVariable("id") Integer id) {userService.deleteStudentById(id);return id;}@GetMapping("/update/{id}/{name}/{hobby}")public Integer update(@PathVariable Integer id,@PathVariable String name,@PathVariable String sex) {userService.updateById(new Student(id,name,sex));return id;}}	
   

7. 启动类上添加注解

   @SpringBootApplication
   @MapperScan("com.apesource.springboot_redis03")
   @EnableCaching
   public class SpringbootRedis03Application {public static void main(String[] args) {SpringApplication.run(SpringbootRedis03Application.class, args);}}
   

8. 启动服务，浏览器访问localhost:8080/findById/1，访问之后刷新再次访问

   注意启动程序服务之前，需要先把redis运行起来

   

   第一次访问时，从数据库中获取的数据

   第二次访问，没有SQL语句，但是也得到了数据，证明cache实现了缓存的作用