springboot自动装配原理-以redis为例
springboot自动装配原理
每天多学一点点~
话不多说，这就开始吧…
文章目录
1.传统的ssm项目配置redis上
- 加入pom依赖
<dependency>
<groupId>org.springframework.data</groupId>
<artifactId>spring-data-redis</artifactId>
<version>2.0.9.RELEASE</version>
</dependency>
<dependency>
<groupId>redis.clients</groupId>
<artifactId>jedis</artifactId>
<version>2.9.0</version>
</dependency>
- 配置xml的bean的配置
//配置连接池
<bean id="poolConfig" class="redis.clients.jedis.JedisPoolConfig">
<property name="minIdle" value="10"></property>
<property name="maxTotal" value="20"></property>
</bean>
//配置连接工厂
<bean id="jedisConnectionFactory" class="org.springframework.data.redis.connection.jedis.JedisConnectionFactory">
<property name="hostName" value="47.104.128.12"></property>
<property name="password" value="123456"></property>
<property name="database" value="0"></property>
<property name="poolConfig" ref="poolConfig"></property>
</bean>
//配置 redisTemplate 模版类
<bean id="redisTemplate" class="org.springframework.data.redis.core.RedisTemplate">
<property name="connectionFactory" ref="jedisConnectionFactory"/>
<!--如果不配置Serializer，那么存储的时候缺省使用String，如果用User类型存储，那么会提示错误User can't cast to String！！ -->
<property name="keySerializer">
<bean class="org.springframework.data.redis.serializer.StringRedisSerializer"/>
</property>
<property name="valueSerializer">
<bean class="org.springframework.data.redis.serializer.GenericJackson2JsonRedisSerializer"/>
</property>
<property name="hashKeySerializer">
<bean class="org.springframework.data.redis.serializer.StringRedisSerializer"/>
</property>
<property name="hashValueSerializer">
<bean class="org.springframework.data.redis.serializer.GenericJackson2JsonRedisSerializer"/>
</property>
</bean>
- 导入配置
@ImportResource(locations = “classpath:beans.xml”) 可以导入xml的配置文件
2.springboot自动装配redis
综上所述 我们发现，若整合redis的时候通过传统的整合，进行了大量的配置,那么我们来看下通过springboot自动装配整合的对比
- 导入依赖
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-redis</artifactId>
</dependency>
-
修改yml配置文件
spring.redis.host=47.104.128.12
spring.redis.port=6379
spring.redis.password=123456 -
修改序列化方式
@Configuration
public class RedisConfig {
@Bean
/**
* @Title: redisTemplate
* @author: xuxiaoxiang
* @Description: 初始化redis
* @param redisConnectionFactory
* @return: RedisTemplate<String,Object>
* @throws
*/
public RedisTemplate<String, Object> redisTemplate(RedisConnectionFactory redisConnectionFactory){
RedisTemplate<String, Object> redisTemplate = new RedisTemplate<String, Object>();
redisTemplate.setConnectionFactory(redisConnectionFactory);
Jackson2JsonRedisSerializer jackson2JsonRedisSerializer = new Jackson2JsonRedisSerializer(Object.class);
/*通用的序列化和反序列化设置
ObjectMapper类是Jackson库的主要类。它提供一些功能将转换成Java对象匹配JSON结构，反之亦然。*/
ObjectMapper objectMapper = new ObjectMapper();
objectMapper.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);
objectMapper.enableDefaultTyping(ObjectMapper.DefaultTyping.NON_FINAL);
jackson2JsonRedisSerializer.setObjectMapper(objectMapper);
redisTemplate.setValueSerializer(jackson2JsonRedisSerializer);
redisTemplate.setKeySerializer(new StringRedisSerializer());
redisTemplate.afterPropertiesSet();
return redisTemplate;
}
}
3.自动装配原理，从@SpringbootApplication入手分析
- AutoConfigurationImportSelector#selectImports方法
public class AutoConfigurationImportSelector
implements DeferredImportSelector, BeanClassLoaderAware, ResourceLoaderAware,
BeanFactoryAware, EnvironmentAware, Ordered {
@Override
public String[] selectImports(AnnotationMetadata annotationMetadata) {
if (!isEnabled(annotationMetadata)) {
return NO_IMPORTS;
}
AutoConfigurationMetadata autoConfigurationMetadata = AutoConfigurationMetadataLoader
.loadMetadata(this.beanClassLoader);
AnnotationAttributes attributes = getAttributes(annotationMetadata);
//去mata-info/spring.factories文件中 查询 EnableAutoConfiguration对于值
List<String> configurations = getCandidateConfigurations(annotationMetadata,
attributes);
//去除重复的配置类，若我们自己写的starter 可能存主重复的
configurations = removeDuplicates(configurations);
Set<String> exclusions = getExclusions(annotationMetadata, attributes);
checkExcludedClasses(configurations, exclusions);
configurations.removeAll(exclusions);
//根据maven 导入的启动器过滤出 需要导入的配置类
configurations = filter(configurations, autoConfigurationMetadata);
fireAutoConfigurationImportEvents(configurations, exclusions);
return StringUtils.toStringArray(configurations);
}
}
//去spring.factories 中去查询EnableAutoConfirution类
private static Map<String, List<String>> loadSpringFactories(@Nullable ClassLoader classLoader) {
MultiValueMap<String, String> result = cache.get(classLoader);
if (result != null) {
return result;
}
try {
Enumeration<URL> urls = (classLoader != null ?
classLoader.getResources(FACTORIES_RESOURCE_LOCATION) :
ClassLoader.getSystemResources(FACTORIES_RESOURCE_LOCATION));
result = new LinkedMultiValueMap<>();
while (urls.hasMoreElements()) {
URL url = urls.nextElement();
UrlResource resource = new UrlResource(url);
Properties properties = PropertiesLoaderUtils.loadProperties(resource);
for (Map.Entry<?, ?> entry : properties.entrySet()) {
List<String> factoryClassNames = Arrays.asList(
StringUtils.commaDelimitedListToStringArray((String) entry.getValue()));
result.addAll((String) entry.getKey(), factoryClassNames);
}
}
cache.put(classLoader, result);
return result;
}
catch (IOException ex) {
throw new IllegalArgumentException("Unable to load factories from location [" +
FACTORIES_RESOURCE_LOCATION + "]", ex);
}
}
- RedisAutoConfiguration类
导入了三个组件 RedisTemplate StringRedisTemplate JedisConnectionConfiguration
@Configuration
@ConditionalOnClass(RedisOperations.class)
@EnableConfigurationProperties(RedisProperties.class)
@Import({ LettuceConnectionConfiguration.class, JedisConnectionConfiguration.class })
public class RedisAutoConfiguration {
//导入redisTemplate
@Bean
@ConditionalOnMissingBean(name = "redisTemplate")
public RedisTemplate<Object, Object> redisTemplate(
RedisConnectionFactory redisConnectionFactory) throws UnknownHostException {
RedisTemplate<Object, Object> template = new RedisTemplate<>();
template.setConnectionFactory(redisConnectionFactory);
return template;
}
@Bean
@ConditionalOnMissingBean
public StringRedisTemplate stringRedisTemplate(
RedisConnectionFactory redisConnectionFactory) throws UnknownHostException {
StringRedisTemplate template = new StringRedisTemplate();
template.setConnectionFactory(redisConnectionFactory);
return template;
}
}
=====================================JedisConnectionConfiguration==========================================
@Configuration
@ConditionalOnClass({ GenericObjectPool.class, JedisConnection.class, Jedis.class })
class JedisConnectionConfiguration extends RedisConnectionConfiguration {
private final RedisProperties properties;
private final List<JedisClientConfigurationBuilderCustomizer> builderCustomizers;
JedisConnectionConfiguration(RedisProperties properties,
ObjectProvider<RedisSentinelConfiguration> sentinelConfiguration,
ObjectProvider<RedisClusterConfiguration> clusterConfiguration,
ObjectProvider<List<JedisClientConfigurationBuilderCustomizer>> builderCustomizers) {
super(properties, sentinelConfiguration, clusterConfiguration);
this.properties = properties;
this.builderCustomizers = builderCustomizers
.getIfAvailable(Collections::emptyList);
}
@Bean
@ConditionalOnMissingBean(RedisConnectionFactory.class)
public JedisConnectionFactory redisConnectionFactory() throws UnknownHostException {
return createJedisConnectionFactory();
}
private JedisConnectionFactory createJedisConnectionFactory() {
JedisClientConfiguration clientConfiguration = getJedisClientConfiguration();
if (getSentinelConfig() != null) {
return new JedisConnectionFactory(getSentinelConfig(), clientConfiguration);
}
if (getClusterConfiguration() != null) {
return new JedisConnectionFactory(getClusterConfiguration(),
clientConfiguration);
}
return new JedisConnectionFactory(getStandaloneConfig(), clientConfiguration);
}
private JedisClientConfiguration getJedisClientConfiguration() {
JedisClientConfigurationBuilder builder = applyProperties(
JedisClientConfiguration.builder());
RedisProperties.Pool pool = this.properties.getJedis().getPool();
if (pool != null) {
applyPooling(pool, builder);
}
if (StringUtils.hasText(this.properties.getUrl())) {
customizeConfigurationFromUrl(builder);
}
customize(builder);
return builder.build();
}
private JedisClientConfigurationBuilder applyProperties(
JedisClientConfigurationBuilder builder) {
if (this.properties.isSsl()) {
builder.useSsl();
}
if (this.properties.getTimeout() != null) {
Duration timeout = this.properties.getTimeout();
builder.readTimeout(timeout).connectTimeout(timeout);
}
return builder;
}
private void applyPooling(RedisProperties.Pool pool,
JedisClientConfiguration.JedisClientConfigurationBuilder builder) {
builder.usePooling().poolConfig(jedisPoolConfig(pool));
}
private JedisPoolConfig jedisPoolConfig(RedisProperties.Pool pool) {
JedisPoolConfig config = new JedisPoolConfig();
config.setMaxTotal(pool.getMaxActive());
config.setMaxIdle(pool.getMaxIdle());
config.setMinIdle(pool.getMinIdle());
if (pool.getMaxWait() != null) {
config.setMaxWaitMillis(pool.getMaxWait().toMillis());
}
return config;
}
}
这里可以看到，spirngboot已经自动帮我们注入了redisTemplate和Jedis了，我们只需要直接用就可以；
注：springboot每个版本可能略有出入，但是整体都差不多，跟着流程走就可以
4.结语
世上无难事，只怕有心人，每天积累一点点，fighting！！！