先看看注解@MapperScan,上面有一行@Import(MapperScannerRegistrar.class),说明它依赖MapperScannerRegistrar.class,spring会将它实例化。部分代码如下:
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.TYPE)
@Documented
@Import(MapperScannerRegistrar.class)
@Repeatable(MapperScans.class)
public @interface MapperScan {
/**
* Alias for the {@link #basePackages()} attribute. Allows for more concise annotation declarations e.g.:
* {@code @MapperScan("org.my.pkg")} instead of {@code @MapperScan(basePackages = "org.my.pkg"})}.
*
* @return base package names
*/
String[] value() default {};
MapperScannerRegistrar.java实现了ImportBeanDefinitionRegistrar接口,因此会回调registerBeanDefinitions方法,往下走会进入重载方法 registerBeanDefinitions(importingClassMetadata, mapperScanAttrs, registry,generateBaseBeanName(importingClassMetadata, 0));
void registerBeanDefinitions(AnnotationMetadata annoMeta, AnnotationAttributes annoAttrs,
BeanDefinitionRegistry registry, String beanName) {
BeanDefinitionBuilder builder = BeanDefinitionBuilder.genericBeanDefinition(MapperScannerConfigurer.class);
builder.addPropertyValue("processPropertyPlaceHolders", true);
Class<? extends Annotation> annotationClass = annoAttrs.getClass("annotationClass");
if (!Annotation.class.equals(annotationClass)) {
builder.addPropertyValue("annotationClass", annotationClass);
}
Class<?> markerInterface = annoAttrs.getClass("markerInterface");
if (!Class.class.equals(markerInterface)) {
builder.addPropertyValue("markerInterface", markerInterface);
}
Class<? extends BeanNameGenerator> generatorClass = annoAttrs.getClass("nameGenerator");
if (!BeanNameGenerator.class.equals(generatorClass)) {
builder.addPropertyValue("nameGenerator", BeanUtils.instantiateClass(generatorClass));
}
Class<? extends MapperFactoryBean> mapperFactoryBeanClass = annoAttrs.getClass("factoryBean");
if (!MapperFactoryBean.class.equals(mapperFactoryBeanClass)) {
builder.addPropertyValue("mapperFactoryBeanClass", mapperFactoryBeanClass);
}
String sqlSessionTemplateRef = annoAttrs.getString("sqlSessionTemplateRef");
if (StringUtils.hasText(sqlSessionTemplateRef)) {
builder.addPropertyValue("sqlSessionTemplateBeanName", annoAttrs.getString("sqlSessionTemplateRef"));
}
String sqlSessionFactoryRef = annoAttrs.getString("sqlSessionFactoryRef");
if (StringUtils.hasText(sqlSessionFactoryRef)) {
builder.addPropertyValue("sqlSessionFactoryBeanName", annoAttrs.getString("sqlSessionFactoryRef"));
}
List basePackages = new ArrayList<>();
basePackages.addAll(
Arrays.stream(annoAttrs.getStringArray("value")).filter(StringUtils::hasText).collect(Collectors.toList()));
basePackages.addAll(Arrays.stream(annoAttrs.getStringArray("basePackages")).filter(StringUtils::hasText)
.collect(Collectors.toList()));
basePackages.addAll(Arrays.stream(annoAttrs.getClassArray("basePackageClasses")).map(ClassUtils::getPackageName)
.collect(Collectors.toList()));
if (basePackages.isEmpty()) {
basePackages.add(getDefaultBasePackage(annoMeta));
}
String lazyInitialization = annoAttrs.getString("lazyInitialization");
if (StringUtils.hasText(lazyInitialization)) {
builder.addPropertyValue("lazyInitialization", lazyInitialization);
}
String defaultScope = annoAttrs.getString("defaultScope");
if (!AbstractBeanDefinition.SCOPE_DEFAULT.equals(defaultScope)) {
builder.addPropertyValue("defaultScope", defaultScope);
}
builder.addPropertyValue("basePackage", StringUtils.collectionToCommaDelimitedString(basePackages));
registry.registerBeanDefinition(beanName, builder.getBeanDefinition());
}
public class MapperScannerConfigurer
implements BeanDefinitionRegistryPostProcessor, InitializingBean, ApplicationContextAware, BeanNameAware {
private String basePackage;
MapperScannerConfigurer实现了BeanDefinitionRegistryPostProcessor,在注入registry之后就会执行postProcessBeanDefinitionRegistry方法
进入
protected Set doScan(String... basePackages) {
Assert.notEmpty(basePackages, "At least one base package must be specified");
Set beanDefinitions = new LinkedHashSet<>();
for (String basePackage : basePackages) {
Set candidates = findCandidateComponents(basePackage);
for (BeanDefinition candidate : candidates) {
ScopeMetadata scopeMetadata = this.scopeMetadataResolver.resolveScopeMetadata(candidate);
candidate.setScope(scopeMetadata.getScopeName());
String beanName = this.beanNameGenerator.generateBeanName(candidate, this.registry);
if (candidate instanceof AbstractBeanDefinition) {
postProcessBeanDefinition((AbstractBeanDefinition) candidate, beanName);
}
if (candidate instanceof AnnotatedBeanDefinition) {
AnnotationConfigUtils.processCommonDefinitionAnnotations((AnnotatedBeanDefinition) candidate);
}
if (checkCandidate(beanName, candidate)) {
BeanDefinitionHolder definitionHolder = new BeanDefinitionHolder(candidate, beanName);
definitionHolder =
AnnotationConfigUtils.applyScopedProxyMode(scopeMetadata, definitionHolder, this.registry);
beanDefinitions.add(definitionHolder);
registerBeanDefinition(definitionHolder, this.registry);
}
}
}
return beanDefinitions;
}
这块就是扫描指定包路径下的所有class文件,放入beanDefinitions返回,回到ClassPathMapperScanner.doScan,从processBeanDefinitions(beanDefinitions);
这些就是所涉及到的主要代码。
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