Redis之sql缓存的具体使用
本文主要介绍了Redis之sql缓存的具体使用,文中通过示例代码介绍的非常详细,具有一定的参考价值,感兴趣的小伙伴们可以参考一下
目录
1.环境搭建
2.Redis配置
3.功能实现
4.缓存注解的使用说明
1.环境搭建
1 2 3 4 5 | <!-- RedisTemplate --> < dependency > < groupId >org.springframework.boot</ groupId > < artifactId >spring-boot-starter-data-redis</ artifactId > </ dependency > |
1 2 3 4 5 6 7 8 9 10 11 12 13 | spring: redis: host: 192.168.8.128 port: 6380 password: 1234 database: 0 timeout: 3000 jedis: pool: max-wait: -1 max-active: -1 max-idle: 20 min-idle: 10 |
2.Redis配置
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 | package com.yzm.redis01.config; import com.fasterxml.jackson.annotation.JsonAutoDetect; import com.fasterxml.jackson.annotation.JsonInclude; import com.fasterxml.jackson.annotation.JsonTypeInfo; import com.fasterxml.jackson.annotation.PropertyAccessor; import com.fasterxml.jackson.core.JsonGenerator; import com.fasterxml.jackson.core.JsonParser; import com.fasterxml.jackson.databind.*; import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; import java.io.IOException; import java.text.SimpleDateFormat; import java.time.LocalDateTime; import java.time.format.DateTimeFormatter; @Configuration public class ObjectMapperConfig { private static final String PATTERN = "yyyy-MM-dd HH:mm:ss" ; @Bean (name = "myObjectMapper" ) public ObjectMapper objectMapper() { JavaTimeModule javaTimeModule = new JavaTimeModule(); javaTimeModule.addSerializer(LocalDateTime. class , new LocalDateTimeSerializer()); javaTimeModule.addDeserializer(LocalDateTime. class , new LocalDateTimeDeserializer()); return new ObjectMapper() // 转换为格式化的json(控制台打印时,自动格式化规范) //.enable(SerializationFeature.INDENT_OUTPUT) // Include.ALWAYS 是序列化对像所有属性(默认) // Include.NON_NULL 只有不为null的字段才被序列化,属性为NULL 不序列化 // Include.NON_EMPTY 如果为null或者 空字符串和空集合都不会被序列化 // Include.NON_DEFAULT 属性为默认值不序列化 .setSerializationInclusion(JsonInclude.Include.NON_NULL) // 如果是空对象的时候,不抛异常 .configure(SerializationFeature.FAIL_ON_EMPTY_BEANS, false ) // 反序列化的时候如果多了其他属性,不抛出异常 .configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false ) // 取消时间的转化格式,默认是时间戳,可以取消,同时需要设置要表现的时间格式 .configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false ) .setDateFormat( new SimpleDateFormat(PATTERN)) // 对LocalDateTime序列化跟反序列化 .registerModule(javaTimeModule) .setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY) // 此项必须配置,否则会报java.lang.ClassCastException: java.util.LinkedHashMap cannot be cast to XXX .enableDefaultTyping(ObjectMapper.DefaultTyping.NON_FINAL, JsonTypeInfo.As.PROPERTY) ; } static class LocalDateTimeSerializer extends JsonSerializer<LocalDateTime> { @Override public void serialize(LocalDateTime value, JsonGenerator gen, SerializerProvider serializers) throws IOException { gen.writeString(value.format(DateTimeFormatter.ofPattern(PATTERN))); } } static class LocalDateTimeDeserializer extends JsonDeserializer<LocalDateTime> { @Override public LocalDateTime deserialize(JsonParser p, DeserializationContext deserializationContext) throws IOException { return LocalDateTime.parse(p.getValueAsString(), DateTimeFormatter.ofPattern(PATTERN)); } } } |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 | package com.yzm.redis01.config; import lombok.extern.slf4j.Slf4j; import org.springframework.cache.interceptor.KeyGenerator; import org.springframework.cache.interceptor.SimpleKey; import java.lang.reflect.Method; import java.util.Arrays; /** * key生成器 */ @Slf4j public class MyKeyGenerator implements KeyGenerator { private static final String NO_PARAM = "[]" ; private static final String NULL_PARAM = "_" ; @Override public Object generate(Object target, Method method, Object... params) { StringBuilder key = new StringBuilder(); key.append(target.getClass().getSimpleName()).append( "." ).append(method.getName()).append( ":" ); if (params.length == 0 ) { return new SimpleKey(key.append(NO_PARAM).toString()); } return new SimpleKey(key.append(Arrays.toString(params).replace( "null" , NULL_PARAM)).toString()); } } |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 | package com.yzm.redis01.config; import com.fasterxml.jackson.databind.ObjectMapper; import org.springframework.cache.CacheManager; import org.springframework.cache.annotation.EnableCaching; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; import org.springframework.data.redis.cache.RedisCacheConfiguration; import org.springframework.data.redis.cache.RedisCacheManager; import org.springframework.data.redis.cache.RedisCacheWriter; import org.springframework.data.redis.connection.RedisConnectionFactory; import org.springframework.data.redis.core.*; import org.springframework.data.redis.serializer.Jackson2JsonRedisSerializer; import org.springframework.data.redis.serializer.RedisSerializationContext; import org.springframework.data.redis.serializer.StringRedisSerializer; import javax.annotation.Resource; import java.time.Duration; @Configuration @EnableCaching // 启动缓存 public class RedisConfig { @Bean (name = "myKeyGenerator" ) public MyKeyGenerator myKeyGenerator() { return new MyKeyGenerator(); } @Resource (name = "myObjectMapper" ) private ObjectMapper objectMapper; /** * 选择redis作为默认缓存工具 */ @Bean public CacheManager cacheManager(RedisConnectionFactory connectionFactory) { RedisCacheWriter redisCacheWriter = RedisCacheWriter.nonLockingRedisCacheWriter(connectionFactory); RedisCacheConfiguration cacheConfiguration = RedisCacheConfiguration .defaultCacheConfig() // 默认缓存时间(秒) .entryTtl(Duration.ofSeconds(300L)) // 序列化key、value .serializeKeysWith(RedisSerializationContext.SerializationPair.fromSerializer( new StringRedisSerializer())) .serializeValuesWith(RedisSerializationContext.SerializationPair.fromSerializer(jackson2JsonRedisSerializer())) // 禁用缓存空值 .disableCachingNullValues(); return new RedisCacheManager(redisCacheWriter, cacheConfiguration); } /** * redisTemplate配置 */ @Bean public RedisTemplate<String, Object> redisTemplate(RedisConnectionFactory factory) { RedisTemplate<String, Object> template = new RedisTemplate<>(); // 配置连接工厂 template.setConnectionFactory(factory); Jackson2JsonRedisSerializer<Object> jacksonSerializer = jackson2JsonRedisSerializer(); StringRedisSerializer stringRedisSerializer = new StringRedisSerializer(); // 使用StringRedisSerializer来序列化和反序列化redis的key,value采用json序列化 template.setKeySerializer(stringRedisSerializer); template.setValueSerializer(jacksonSerializer); // 设置hash key 和value序列化模式 template.setHashKeySerializer(stringRedisSerializer); template.setHashValueSerializer(jacksonSerializer); //支持事务 template.setEnableTransactionSupport( true ); template.afterPropertiesSet(); return template; } private Jackson2JsonRedisSerializer<Object> jackson2JsonRedisSerializer() { //使用Jackson2JsonRedisSerializer来序列化和反序列化redis的value值(默认使用JDK的序列化方式) Jackson2JsonRedisSerializer<Object> jacksonSerializer = new Jackson2JsonRedisSerializer<>(Object. class ); jacksonSerializer.setObjectMapper(objectMapper); return jacksonSerializer; } } |
3.功能实现
新增、更新、删除、查询数据时,对缓存执行对应相同的操作
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 | package com.yzm.redis01.entity; import lombok.AllArgsConstructor; import lombok.Builder; import lombok.Data; import lombok.NoArgsConstructor; import lombok.experimental.Accessors; import java.io.Serializable; import java.time.LocalDateTime; import java.util.Date; @Data @Builder @NoArgsConstructor @AllArgsConstructor @Accessors (chain = true ) public class User implements Serializable { private static final long serialVersionUID = -2468903864827432779L; private Integer id; private String username; private String password; private Date createDate; private LocalDateTime updateDate; } |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 | package com.yzm.redis01.service; import com.yzm.redis01.entity.User; import java.util.List; public interface UserService { User saveUser(User user); User updateUser(User user); int deleteUser(Integer id); void deleteAllCache(); User getUserById(Integer id); List<User> selectAll(); List<User> findAll(Object... params); } |
为了简便,数据不从数据库获取,这里是创建Map存储数据实现
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 | package com.yzm.redis01.service.impl; import com.yzm.redis01.entity.User; import com.yzm.redis01.service.UserService; import lombok.extern.slf4j.Slf4j; import org.springframework.cache.annotation.CacheConfig; import org.springframework.cache.annotation.CacheEvict; import org.springframework.cache.annotation.CachePut; import org.springframework.cache.annotation.Cacheable; import org.springframework.stereotype.Service; import java.time.LocalDateTime; import java.util.*; @Slf4j @Service @CacheConfig (cacheNames = "users" ) public class UserServiceImpl implements UserService { private static final Map<Integer, User> userMap; static { userMap = new HashMap<>(); userMap.put(userMap.size() + 1 , User.builder() .id(userMap.size() + 1 ).username( "root" ).password( "root" ).createDate( new Date()).updateDate(LocalDateTime.now()).build()); userMap.put(userMap.size() + 1 , User.builder() .id(userMap.size() + 1 ).username( "admin" ).password( "admin" ).createDate( new Date()).updateDate(LocalDateTime.now()).build()); } @Override @CachePut (key = "#result.id" , condition = "#result.id gt 0" ) public User saveUser(User user) { log.info( "保存数据" ); int id = userMap.size() + 1 ; User build = User.builder() .id(id) .username(user.getUsername()) .password(user.getPassword()) .createDate( new Date()) .updateDate(LocalDateTime.now()) .build(); userMap.put(id, build); return build; } @Override @CachePut (key = "#user.id" , unless = "#result eq null" ) public User updateUser(User user) { log.info( "更新数据" ); if (userMap.containsKey(user.getId())) { User update = userMap.get(user.getId()); update.setUsername(user.getUsername()) .setPassword(user.getPassword()) .setUpdateDate(LocalDateTime.now()); userMap.replace(user.getId(), update); return update; } return null ; } @Override @CacheEvict (key = "#id" , condition = "#result gt 0" ) public int deleteUser(Integer id) { log.info( "删除数据" ); if (userMap.containsKey(id)) { userMap.remove(id); return 1 ; } return 0 ; } @Override @CacheEvict (allEntries = true ) public void deleteAllCache() { log.info( "清空缓存" ); } @Override @Cacheable (key = "#id" , condition = "#id gt 1" ) public User getUserById(Integer id) { log.info( "查询用户" ); return userMap.get(id); } @Override @Cacheable (key = "#root.methodName" ) public List<User> selectAll() { log.info( "查询所有" ); return new ArrayList<>(userMap.values()); } @Override @Cacheable (keyGenerator = "myKeyGenerator" ) public List<User> findAll(Object... params) { log.info( "查询所有" ); return new ArrayList<>(userMap.values()); } } |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 | package com.yzm.redis01.controller; import com.yzm.redis01.entity.User; import com.yzm.redis01.service.UserService; import org.springframework.web.bind.annotation.GetMapping; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RequestParam; import org.springframework.web.bind.annotation.RestController; import java.util.List; @RestController @RequestMapping ( "/user" ) public class UserController { private final UserService userService; public UserController(UserService userService) { this .userService = userService; } @GetMapping ( "/saveUser" ) public void saveUser() { User user = new User(); user.setUsername( "yzm" ); user.setPassword( "yzm" ); System.out.println(userService.saveUser(user)); } @GetMapping ( "/updateUser" ) public void updateUser(Integer id) { User user = new User(); user.setId(id); user.setUsername( "yzm" ); user.setPassword( "123" ); System.out.println(userService.updateUser(user)); } @GetMapping ( "/deleteUser" ) public void deleteUser( @RequestParam Integer id) { System.out.println(userService.deleteUser(id)); } @GetMapping ( "/deleteAllCache" ) public void deleteAllCache() { userService.deleteAllCache(); } @GetMapping ( "/getUserById" ) public void getUserById( @RequestParam Integer id) { System.out.println(userService.getUserById(id)); } @GetMapping ( "/selectAll" ) public void selectAll() { List<User> users = userService.selectAll(); users.forEach(System.out::println); } } |
4.缓存注解的使用说明
@CacheConfig:注解在类上,表示该类所有缓存方法使用统一指定的缓存区,也可以作用在方法上
@CacheAble:注解在方法上,应用到读数据的方法上,如查找方法:调用方法之前根据条件判断是否从缓存获取相应的数据,缓存没有数据,方法执行后添加到缓存
#id 直接使用参数名
#p0 p0对应参数列表的第一个参数,以此类推
#user.id 参数是对象时,使用对象属性
#root. 可以点出很多方法
#root.methodName
#result 返回值
http://localhost:8080/user/getUserById?id=1
http://localhost:8080/user/getUserById?id=2
http://localhost:8080/user/selectAll
@Cacheable运行流程:在调用方法之前判断condition,如果为true,则查缓存;没有缓存就调用方法并将数据添加到缓存;condition=false就与缓存无关了
@CachePut:注解在方法上,应用到写数据的方法上,如新增/修改方法,调用方法之后根据条件判断是否添加/更新相应的数据到缓存:
http://localhost:8080/user/saveUser
condition条件为true,添加到缓存,根据id查询直接从缓存获取
http://localhost:8080/user/getUserById?id=3
http://localhost:8080/user/updateUser?id=3
http://localhost:8080/user/getUserById?id=3
条件condition=true,执行缓存操作
条件unless=false,执行缓存操作;跟condition相反
@CacheEvict 注解在方法上,应用到删除数据的方法上,如删除方法,调用方法之后根据条件判断是否从缓存中移除相应的数据
http://localhost:8080/user/saveUser
http://localhost:8080/user/getUserById?id=3
http://localhost:8080/user/deleteUser?id=3
自定义缓存key自动生成器
1 2 3 4 5 6 | @Override @Cacheable (keyGenerator = "myKeyGenerator" ) public List<User> findAll(Object... params) { log.info( "查询所有" ); return new ArrayList<>(userMap.values()); } |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 | @Slf4j public class MyKeyGenerator implements KeyGenerator { private static final String NO_PARAM = "[]" ; private static final String NULL_PARAM = "_" ; @Override public Object generate(Object target, Method method, Object... params) { StringBuilder key = new StringBuilder(); key.append(target.getClass().getSimpleName()).append( "." ).append(method.getName()).append( ":" ); if (params.length == 0 ) { return new SimpleKey(key.append(NO_PARAM).toString()); } return new SimpleKey(key.append(Arrays.toString(params).replace( "null" , NULL_PARAM)).toString()); } } |
http://localhost:8080/user/findAll
http://localhost:8080/user/findAll?id=123
http://localhost:8080/user/findAll?username=yzm
@Caching
有时候我们可能组合多个Cache注解使用;比如用户新增成功后,我们要添加id–>user;username—>user;email—>user的缓存;
此时就需要@Caching组合多个注解标签了。
1 2 3 4 5 6 7 8 | @Caching ( put = { @CachePut (value = "users" , key = "#user.id" ), @CachePut (value = "users" , key = "#user.username" ), @CachePut (value = "users" , key = "#user.email" ) } ) public User save(User user) {} |
到此这篇关于Redis之sql缓存的具体使用的文章就介绍到这了
原文链接:https://blog.csdn.net/qq_43654581/article/details/121677623