MapperScan添加动态配置(占位符)
在对Mybatis自动扫描配置中，使用注解配置时，@MapperScan中的配置，通常配置如下：
@MapperScan(basePackages = {"com.aa.**.mapper","com.bb.**.mapper"}, sqlSessionFactoryRef = "sqlSessionFactory")
不支持在yml或properties文件中动态配置。因为MapperScan注解功能的实现类MapperScannerRegistrar实现的是ImportBeanDefinitionRegistrar。在对@Configuration注解标记的类配置时，实现占位符功能的PropertyPlaceholderAutoConfiguration还没有开始加载。
MapperScannerRegistrard的核心代码如下
ListbasePackages = new ArrayList(); basePackages.addAll((Collection)Arrays.stream(annoAttrs.getStringArray("value")).filter(StringUtils::hasText).collect(Collectors.toList())); basePackages.addAll((Collection)Arrays.stream(annoAttrs.getStringArray("basePackages")).filter(StringUtils::hasText).collect(Collectors.toList())); basePackages.addAll((Collection)Arrays.stream(annoAttrs.getClassArray("basePackageClasses")).map(ClassUtils::getPackageName).collect(Collectors.toList())); scanner.registerFilters(); scanner.doScan(StringUtils.toStringArray(basePackages));
从上面代码中可以看出
为了拓展支持占位符动态配置，只需把basePackages的加载改写即可。
1、参考MapperScannerRegistrard，实现 ImportBeanDefinitionRegistrar和ResourceLoaderAware两个接口
2、为了动态读取配置文件信息，需要引入Environment，所以实现EnvironmentAware接口
3、代码
MapperScannerRegistrar.java
import org.mybatis.spring.mapper.ClassPathMapperScanner;
import org.mybatis.spring.mapper.MapperFactoryBean;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.BeanUtils;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.beans.factory.support.BeanNameGenerator;
import org.springframework.context.EnvironmentAware;
import org.springframework.context.ResourceLoaderAware;
import org.springframework.context.annotation.ImportBeanDefinitionRegistrar;
import org.springframework.context.support.PropertySourcesPlaceholderConfigurer;
import org.springframework.core.annotation.AnnotationAttributes;
import org.springframework.core.env.Environment;
import org.springframework.core.io.ResourceLoader;
import org.springframework.core.type.AnnotationMetadata;
import org.springframework.util.ClassUtils;
import org.springframework.util.StringUtils;
import java.lang.annotation.Annotation;
import java.util.*;
import java.util.stream.Collectors;
public class MapperScannerRegistrar implements ImportBeanDefinitionRegistrar, ResourceLoaderAware,EnvironmentAware {
private Environment environment;
private ResourceLoader resourceLoader;
private static final Logger logger = LoggerFactory.getLogger(MapperScannerRegistrar. class);
@Override
public void setEnvironment(Environment environment) {
this.environment = environment;
}
@Override
public void setResourceLoader(ResourceLoader resourceLoader) {
this.resourceLoader = resourceLoader;
}
@Override
public void registerBeanDefinitions(AnnotationMetadata importingClassMetadata, BeanDefinitionRegistry registry) {
AnnotationAttributes mapperScanAttrs = AnnotationAttributes.fromMap(importingClassMetadata.getAnnotationAttributes(MapperScanner.class.getName()));
if (mapperScanAttrs != null) {
this.registerBeanDefinitions(mapperScanAttrs, registry);
}
}
void registerBeanDefinitions(AnnotationAttributes annoAttrs, BeanDefinitionRegistry registry) {
ClassPathMapperScanner scanner = new ClassPathMapperScanner(registry);
Optional var10000 = Optional.ofNullable(this.resourceLoader);
Objects.requireNonNull(scanner);
Class annotationClass = annoAttrs.getClass("annotationClass");
if (!Annotation.class.equals(annotationClass)) {
scanner.setAnnotationClass(annotationClass);
}
Class markerInterface = annoAttrs.getClass("markerInterface");
if (!Class.class.equals(markerInterface)) {
scanner.setMarkerInterface(markerInterface);
}
Class generatorClass = annoAttrs.getClass("nameGenerator");
if (!BeanNameGenerator.class.equals(generatorClass)) {
scanner.setBeanNameGenerator((BeanNameGenerator) BeanUtils.instantiateClass(generatorClass));
}
Class mapperFactoryBeanClass = annoAttrs.getClass("factoryBean");
if (!MapperFactoryBean.class.equals(mapperFactoryBeanClass)) {
scanner.setMapperFactoryBeanClass(mapperFactoryBeanClass);
}
scanner.setSqlSessionTemplateBeanName(annoAttrs.getString("sqlSessionTemplateRef"));
scanner.setSqlSessionFactoryBeanName(annoAttrs.getString("sqlSessionFactoryRef"));
List basePackages = new ArrayList();
basePackages.addAll(Arrays.stream(annoAttrs.getStringArray("value")).filter(StringUtils::hasText).collect(Collectors.toList()));
for (String pkg : annoAttrs.getStringArray("basePackages")) {
if (StringUtils.hasText(pkg)) {
String value = parsePlaceHolder(pkg);
if(StringUtils.hasText(value)){
List valueList = Arrays.asList(value.split(","));
for(String base : valueList){
basePackages.add(base);
}
}
}
}
basePackages.addAll(Arrays.stream(annoAttrs.getClassArray("basePackageClasses")).map(ClassUtils::getPackageName).collect(Collectors.toList()));
scanner.registerFilters();
scanner.doScan(StringUtils.toStringArray(basePackages));
}
private String parsePlaceHolder(String pro) {
if (StringUtils.hasText(pro) && pro.contains(PropertySourcesPlaceholderConfigurer.DEFAULT_PLACEHOLDER_PREFIX)) {
String value = environment.getProperty(pro.substring(2, pro.length() - 1));
if (logger.isDebugEnabled()) {
logger.debug("find placeholder value " + value + " for key " + pro);
}
if (null == value) {
throw new IllegalArgumentException("property " + pro + " can not find!!!");
}
return value;
}
return pro;
}
}
MapperScanner.java
import org.mybatis.spring.mapper.MapperFactoryBean;
import org.springframework.beans.factory.support.BeanNameGenerator;
import org.springframework.context.annotation.Import;
import java.lang.annotation.*;
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.TYPE})
@Documented
@Import({MapperScannerRegistrar.class})
public @interface MapperScanner {
String[] value() default {};
String[] basePackages() default {};
Class[] basePackageClasses() default {};
Class nameGenerator() default BeanNameGenerator.class;
Class annotationClass() default Annotation.class;
Class markerInterface() default Class.class;
String sqlSessionTemplateRef() default "";
String sqlSessionFactoryRef() default "";
Class factoryBean() default MapperFactoryBean.class;
}
4、使用MapperScanner，占位符扫描配置
@MapperScanner(basePackages = { "${mybatis.mapperScanner.basePackage}" }, sqlSessionFactoryRef = "sqlSessionFactory")
mybatis: mapperScanner: basePackage: com.aa.**.mapper,com.bb.**.mapper
关于@MapperScan配置
问题
org.apache.ibatis.binding.BindingException: Invalid bound statement (not found): top.yangzefeng.usercenter.user.service.UserService.getById
解决方案
常用配置：
@MapperScan("top.yangzefeng.usercenter.**.mapper")
@MapperScan("com.demo.mapper")：扫描指定包中的接口@MapperScan("com.demo.*.mapper")：一个代表任意字符串，但只代表一级包，比如可以扫到com.demo.aaa.mapper，不能扫到com.demo.aaa.bbb.mapper@MapperScan("com.demo.**.mapper")：两个代表任意个包，比如可以扫到com.demo.aaa.mapper，也可以扫到com.demo.aaa.bbb.mapper
以上为个人经验，希望能给大家一个参考，也希望大家多多支持脚本之家。