1000. JAVA基礎

1. 泛型

1.1 泛型和Object的區別

泛型和Object的區別 什么時候用泛型 什么時候使用Object

1100. Spring

1. 常用注解

1.1 @ControllerAdvice注解

spring的@ControllerAdvice注解

1.2 緩存@Cacheable

@Cacheable使用詳解
@Cacheable 注解在方法上，表示該方法的返回結果是可以緩存的。也就是說，該方法的返回結果會放在緩存中，以便于以后使用相同的參數調用該方法時，會返回緩存中的值，而不會實際執行該方法。

依賴

    <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>

配置類

package com.imooc.mall.config;import java.time.Duration;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;/*** 描述：     緩存的配置類*/
@Configuration
@EnableCaching
public class CachingConfig {@Beanpublic RedisCacheManager redisCacheManager(RedisConnectionFactory connectionFactory) {RedisCacheWriter redisCacheWriter = RedisCacheWriter.lockingRedisCacheWriter(connectionFactory);RedisCacheConfiguration cacheConfiguration = RedisCacheConfiguration.defaultCacheConfig();//超時時間30scacheConfiguration = cacheConfiguration.entryTtl(Duration.ofSeconds(30));RedisCacheManager redisCacheManager = new RedisCacheManager(redisCacheWriter, cacheConfiguration);return redisCacheManager;}
}

啟動類需要@EnableCaching描述

package com.imooc.mall;import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cache.annotation.EnableCaching;
import springfox.documentation.swagger2.annotations.EnableSwagger2;@SpringBootApplication
@MapperScan(basePackages = "com.imooc.mall.model.dao")
@EnableSwagger2
@EnableCaching
public class MallApplication {public static void main(String[] args) {SpringApplication.run(MallApplication.class, args);}}

應用

	import org.springframework.cache.annotation.Cacheable;@Override@Cacheable(value = "listCategoryForCustomer")public List<CategoryVO> listCategoryForCustomer() {ArrayList<CategoryVO> categoryVOList = new ArrayList<>();recursivelyFindCategories(categoryVOList, 0);return categoryVOList;}

2. 常用方法

2.1 BeanUtils.copyProperties的用法

BeanUtils.copyProperties的用法(超詳細，建議收藏)

如果有兩個具有很多相同屬性名的JavaBean對象a和b，想把a中的屬性賦值到b

3. 常用功能組件

3.1 過濾器Filter

Filter（過濾器）簡介

JavaWeb過濾器(Filter)詳解

2000. Linux應用