Spring缓存机制和Redis的结合
- 这里使用reids作为缓存。
- 使用Mybatis来操作数据库。
- 并使用Spring的@Cacheable，@CachePut，@CacheEvict注解来操作redis缓存。
1 准备环境
包结构
1 Spring配置 RootConfig.java
@Configuration
@ComponentScan(basePackages="cn.wu")
@EnableTransactionManagement
public class RootConfig {
// 配置数据源
@Bean
public DataSource initDataSource() {
DataSource dataSource = null;
Properties properties = new Properties();
properties.setProperty("driverClassName", "com.mysql.jdbc.Driver");
properties.setProperty("url", "jdbc:mysql://localhost:3306/ssm?useSSL=false");
properties.setProperty("username", "root");
properties.setProperty("password", "数据库连接密码");
try {
dataSource = BasicDataSourceFactory.createDataSource(properties);
} catch (Exception e) {
e.printStackTrace();
}
return dataSource;
}
// 配置mybatis的SqlSession的工厂
@Bean(name="sqlSessionFactory")
public SqlSessionFactoryBean initSqlSessionFactoryBean() {
SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
sqlSessionFactoryBean.setDataSource(initDataSource()); // 设置dataSource
Resource resource = new ClassPathResource("mybatis-config.xml");
sqlSessionFactoryBean.setConfigLocation(resource); // 设置mybatis配置文件
return sqlSessionFactoryBean;
}
// 配置mybatis映射器的扫描器
@Bean
public MapperScannerConfigurer initMapperScannerConfigurer() {
MapperScannerConfigurer mapperScannerConfigurer = new MapperScannerConfigurer();
mapperScannerConfigurer.setBasePackage("cn.wu.mapper");
mapperScannerConfigurer.setSqlSessionFactoryBeanName("sqlSessionFactory");
mapperScannerConfigurer.setAnnotationClass(Repository.class);
return mapperScannerConfigurer;
}
// 配置事务管理器
@Bean
public PlatformTransactionManager initTransactionManager() {
DataSourceTransactionManager transactionManage = new DataSourceTransactionManager();
transactionManage.setDataSource(initDataSource());
return transactionManage;
}
}
mybatis-config.xml代码：
2 使用Redis作为缓存的相关配置RedisConfig.java
@Configuration
@EnableCaching // 让Spring IOC容器启动缓存机制
public class RedisConfig {
@Bean
public RedisConnectionFactory initRedisConnectionFactory() {
JedisPoolConfig poolConfig = new JedisPoolConfig();
poolConfig.setMaxIdle(50);
poolConfig.setMaxTotal(100);
poolConfig.setMaxWaitMillis(20000);
JedisConnectionFactory connectionFactory = new JedisConnectionFactory(poolConfig);
connectionFactory.setHostName("localhost");
connectionFactory.setPort(6379);
return connectionFactory;
}
@Bean
public RedisTemplate initRedisTemplate() {
RedisTemplate redisTemplate = new RedisTemplate();
redisTemplate.setConnectionFactory(initRedisConnectionFactory());
StringRedisSerializer stringSerializer = new StringRedisSerializer();
JdkSerializationRedisSerializer jdkSSerializer = new JdkSerializationRedisSerializer();
redisTemplate.setKeySerializer(stringSerializer);
redisTemplate.setValueSerializer(jdkSSerializer);
redisTemplate.setDefaultSerializer(stringSerializer);
redisTemplate.setHashKeySerializer(stringSerializer);
redisTemplate.setHashValueSerializer(jdkSSerializer);
return redisTemplate;
}
/*
* 配置Spring缓存管理器
* 这里的缓存管理器是RedisCacheManager。
* RedisCacheManager实现了Spring的CacheManager接口
*/
@Bean(name = "redisCacheManager")
public CacheManager initRedisCacheManager(@Autowired RedisTemplate redisTemplate) {
RedisCacheManager redisCacheManager = new RedisCacheManager(redisTemplate);
// 设置键的超时时间为10分钟
redisCacheManager.setDefaultExpiration(600L);
// 设置缓存名称
List cacheNames = new ArrayList<>();
cacheNames.add("redisCacheManager");
redisCacheManager.setCacheNames(cacheNames);
return redisCacheManager;
}
}
2 Mybatis映射器代码与配置
1 Role.java
public class Role implements Serializable{
private static final long serialVersionUID = -4295925571801283375L;
private Long id;
private String roleName;
private String note;
// getter setter
}
2 RoleMapper.java
@Repository
public interface RoleMapper {
Role getRole(Long id);
int deleteRole(Long id);
int insertRole(Role role);
int updateRole(Role role);
List findRoles(@Param("roleName")String roleName, @Param("note")String note);
}
3 RoleMapper.xml
delete from t_role where
id = #{id}
insert into t_role(role_name,
note) values(#{roleName}, #{note})
update t_role set
role_name = #{roleName}, note = #{note} where id = #{id}
3 使用映射器的Service代码
RoleService.java
public interface RoleService {
Role getRole(Long id);
int deleteRole(Long id);
Role insertRole(Role role);
Role updateRole(Role role);
List findRoles(String roleName, String note);
}
RoleServiceImpl.java
@Service
public class RoleServiceImpl implements RoleService {
@Autowired
private RoleMapper roleMapper;
/**
* value = "redisCacheManager"表示使用的缓存名称（这里使用的是RedisConfig中配置的缓存管理器名称）
* key = "'redis_role_'+#id" 表示缓存到redis时的key
*
* @Cacheable 表示在执行getRole()代码前，先到redis查询对应key的缓存，
* 若存在缓存则直接返回缓存；
* 若缓存不存在，则执行数据库查询代码，然后将结果缓存到redis，其key为"'redis_role_'+#id"。
* 所以@Cacheable 适合放在查询命中率高的方法上
*/
@Override
@Transactional(isolation = Isolation.READ_COMMITTED, propagation = Propagation.REQUIRED)
@Cacheable(value = "redisCacheManager", key = "'redis_role_'+#id")
public Role getRole(Long id) {
return roleMapper.getRole(id);
}
/**
* @CachePut ， 不管有没有缓存，insertRole()代码都会去执行，然后将返回的结果缓存到redis中。
* 所以@CachePut 适合放在插入和更新数据库的方法上。
*/
@Override
@Transactional(isolation = Isolation.READ_COMMITTED, propagation = Propagation.REQUIRED)
@CachePut(value="redisCacheManager",key="'redis_role_'+#role.id")
public Role insertRole(Role role) {
roleMapper.insertRole(role);
return role;
}
/**
* @CacheEvict 表示删除redis中的缓存，这里删除的时key="'redis_role_'+#id"的缓存
*/
@Override
@Transactional(isolation = Isolation.READ_COMMITTED, propagation = Propagation.REQUIRED)
@CacheEvict(value="redisCacheManager", key="'redis_role_'+#id")
public int deleteRole(Long id) {
return roleMapper.deleteRole(id);
}
@Override
@Transactional(isolation = Isolation.READ_COMMITTED, propagation = Propagation.REQUIRED)
@CachePut(value="redisCacheManager", key="'redis_role_'+#role.id")
public Role updateRole(Role role) {
roleMapper.updateRole(role);
return role;
}
@Override
public List findRoles(String roleName, String note) {
return roleMapper.findRoles(roleName, note);
}
}
4 测试
public class Main {
public static void main(String[] args) {
ApplicationContext context = new AnnotationConfigApplicationContext(RootConfig.class, RedisConfig.class);
RoleService roleService = context.getBean(RoleService.class);
Role role = new Role();
role.setRoleName("李华");
role.setNote("好人");
roleService.insertRole(role); // reids中缓存了key=redis_role_67，值为role对象
System.out.println(role); // Role [id=67, roleName=李华, note=好人]
Role role2 = roleService.getRole(role.getId()); // 没有执行数据库查询语句，而是直接返回了redis中的缓存
role2.setNote("备注好人");
roleService.updateRole(role2)；// 更新了数据库中的记录和reids中的缓存
}
}