Mongo 的free schema,提供了灵活的数据结构,和快速开发的能力,但是也造成了松散的数据组织形式。比如说有些字段不允许为null的,需要符合一定格式的。也就是数据库的校验,validator。这个功能在mongo 3.2才提供,之前是并没有的。这里提供一种基于MongoEvent的解决方案,来实现对于数据的校验。
提供了Mongo Event的类型,以及处理方法
public void onApplicationEvent(MongoMappingEvent<?> event) {
// 根据事件类型,来执行不同的方法
if (event instanceof AfterLoadEvent) {
AfterLoadEvent<?> afterLoadEvent = (AfterLoadEvent<?>) event;
if (domainClass.isAssignableFrom(afterLoadEvent.getType())) {
onAfterLoad((AfterLoadEvent<E>) event);
}
return;
}
if (event instanceof AbstractDeleteEvent) {
Class<?> eventDomainType = ((AbstractDeleteEvent) event).getType();
if (eventDomainType != null && domainClass.isAssignableFrom(eventDomainType)) {
if (event instanceof BeforeDeleteEvent) {
onBeforeDelete((BeforeDeleteEvent<E>) event);
}
if (event instanceof AfterDeleteEvent) {
onAfterDelete((AfterDeleteEvent<E>) event);
}
}
return;
}
Object source = event.getSource();
// Check for matching domain type and invoke callbacks
if (source != null && !domainClass.isAssignableFrom(source.getClass())) {
return;
}
if (event instanceof BeforeConvertEvent) {
onBeforeConvert((BeforeConvertEvent<E>) event);
} else if (event instanceof BeforeSaveEvent) {
onBeforeSave((BeforeSaveEvent<E>) event);
} else if (event instanceof AfterSaveEvent) {
onAfterSave((AfterSaveEvent<E>) event);
} else if (event instanceof AfterConvertEvent) {
onAfterConvert((AfterConvertEvent<E>) event);
}
}
protected <T> void doInsert(String collectionName, T objectToSave, MongoWriter<T> writer) {
initializeVersionProperty(objectToSave);
// 调用onBeforeConvert
maybeEmitEvent(new BeforeConvertEvent<T>(objectToSave, collectionName));
assertUpdateableIdIfNotSet(objectToSave);
DBObject dbDoc = toDbObject(objectToSave, writer);
// 调用onBeforeSaveEvent
maybeEmitEvent(new BeforeSaveEvent<T>(objectToSave, dbDoc, collectionName));
Object id = insertDBObject(collectionName, dbDoc, objectToSave.getClass());
populateIdIfNecessary(objectToSave, id);
// 调用onAfterSaveEvent
maybeEmitEvent(new AfterSaveEvent<T>(objectToSave, dbDoc, collectionName));
}
提供一个@MongoAutoId的注解,然后onBeforeConvert事件中进行转换。
package com.fs.mongo.dao;
import com.fs.mongo.annotation.MongoAutoId;
import com.fs.mongo.model.MongoId;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.mongodb.core.FindAndModifyOptions;
import org.springframework.data.mongodb.core.MongoTemplate;
import org.springframework.data.mongodb.core.mapping.event.AbstractMongoEventListener;
import org.springframework.data.mongodb.core.mapping.event.BeforeConvertEvent;
import org.springframework.data.mongodb.core.mapping.event.BeforeSaveEvent;
import org.springframework.data.mongodb.core.query.Criteria;
import org.springframework.data.mongodb.core.query.Query;
import org.springframework.data.mongodb.core.query.Update;
import org.springframework.stereotype.Repository;
import org.springframework.util.ReflectionUtils;
/**
* @author cnstonefang@gmail.com
*/
@Repository
public class MongoListener extends AbstractMongoEventListener<Object> {
private static final Logger LOG = LoggerFactory.getLogger(MongoListener.class);
@Autowired
private MongoTemplate mongoTemplate;
@Override
public void onBeforeConvert(final BeforeConvertEvent<Object> event) {
final Object source = event.getSource();
if (source != null) {
ReflectionUtils.doWithFields(source.getClass(), new ReflectionUtils.FieldCallback() {
@Override
public void doWith(final java.lang.reflect.Field field)
throws IllegalArgumentException, IllegalAccessException {
ReflectionUtils.makeAccessible(field);
if (field.isAnnotationPresent(MongoAutoId.class) && field.get(source) == null) {
field.set(source, getId(event.getCollectionName()));
}
}
});
}
}
/**
* 获取自增id
* 这边是利用mongo的findAndModify的原子性实现的
* 也可以使用redis来实现
*/
private Long getId(final String collName) {
final Query query = new Query().addCriteria(
new Criteria(MongoId.FIELD_COLLNAME).is(collName));
final Update update = new Update();
update.inc(MongoId.FIELD_SEQID, 1);
final FindAndModifyOptions options = new FindAndModifyOptions().upsert(true).returnNew
(true);
final MongoId sequence = mongoTemplate.findAndModify(query, update, options,
MongoId.class);
return sequence.getSeqId();
}
}