Mongo的ORM框架的学习Morphia(十一) morphia自定义注解、转换器的使用
转自：http://topmanopensource.iteye.com/blog/1439689
???????? http://topmanopensource.iteye.com/blog/1439692
?
一：自定义注解的使用
?
????? 在特殊的情况下，定义服务端注解，减少配置。下面代码为注解的使用：
注解类：
package com.easyway.mongodb.morphia.annotation;import java.lang.annotation.ElementType;import java.lang.annotation.Retention;import java.lang.annotation.RetentionPolicy;import java.lang.annotation.Target;/** * * @Title: 自定义注释的使用 * @Description: 实现TODO * @Copyright:Copyright (c) 2011 * @Company:易程科技股份有限公司 * @Date:2012-3-2 * @author * @version 1.0 */@Retention(RetentionPolicy.RUNTIME)@Target({ElementType.FIELD})public @interface Lowercase {}?package com.easyway.mongodb.morphia.annotation;import com.google.code.morphia.annotations.Entity;import com.google.code.morphia.annotations.Id;/** * 用于存储MorphiaInfo的信息 * @Title: * @Description: 实现TODO * @Copyright:Copyright (c) 2011 * @Company:易程科技股份有限公司 * @Date:2012-3-2 * @author * @version 1.0 */@Entitypublic class MorphiaInfo {private @Id String id;//自定义注释的使用@Lowercaseprivate String morphiaName;private String version;public String getId() {return id;}public void setId(String id) {this.id = id;}public String getMorphiaName() {return morphiaName;}public void setMorphiaName(String morphiaName) {this.morphiaName = morphiaName;}public String getVersion() {return version;}public void setVersion(String version) {this.version = version;}}?package com.easyway.mongodb.morphia.annotation;import java.util.List;import com.google.code.morphia.EntityInterceptor;import com.google.code.morphia.mapping.MappedClass;import com.google.code.morphia.mapping.MappedField;import com.google.code.morphia.mapping.Mapper;import com.mongodb.DBObject;/** * 使用拦截器机制的使用用于特定的处理 * * @Title: * @Description: 实现自定义注释的使用 * @Copyright:Copyright (c) 2011 * @Company:易程科技股份有限公司 * @Date:2012-3-2 * @author * @version 1.0 */public class ToLowercaseHelper implements EntityInterceptor {public void postLoad(Object ent, DBObject dbObj, Mapper mapr) {}public void postPersist(Object ent, DBObject dbObj, Mapper mapr) {}/** * 保存的前的拦截 */public void preSave(Object ent, DBObject dbObj, Mapper mapr) {}/** * 加载前的操作 */public void preLoad(Object ent, DBObject dbObj, Mapper mapr) {}/** * 持久化前的处理 * (non-Javadoc) * @see com.google.code.morphia.EntityInterceptor#prePersist(java.lang.Object, com.mongodb.DBObject, com.google.code.morphia.mapping.Mapper) */public void prePersist(Object ent, DBObject dbObj, Mapper mapr) {//获取映射的类MappedClass mc = mapr.getMappedClass(ent);//获取映射的特定注释的类字段List<MappedField> toLowercase = mc.getFieldsAnnotatedWith(Lowercase.class);//针对映射特定的注释类的处理for (MappedField mf : toLowercase) {try {Object fieldValue = mf.getFieldValue(ent);dbObj.put(mf.getNameToStore() + "_lowercase", fieldValue.toString().toLowerCase());} catch (Exception e) {throw new RuntimeException(e);}}}}?
package com.easyway.mongodb.morphia.annotation;import com.google.code.morphia.AdvancedDatastore;import com.google.code.morphia.Datastore;import com.google.code.morphia.Morphia;import com.google.code.morphia.mapping.MappedField;import com.mongodb.DB;import com.mongodb.Mongo;/** * * @Title: 简单的测试类 * @Description: 实现TODO * @Copyright:Copyright (c) 2011 * @Company:易程科技股份有限公司 * @Date:2012-3-2 * @author * @version 1.0 */public class AnnotationApp {public static void main(String[] args) {try { String dbName="test"; //创建一个Mongo对象 Mongo mongo = new Mongo("localhost"); //获取Mongo的数据库对象 DB db = mongo.getDB(dbName); //创建一个Morphia对象 Morphia morphia = new Morphia(); //创建一个Datastore对象用于操作数据 Datastore ds= morphia.createDatastore(mongo, db.getName()); AdvancedDatastore ads = (AdvancedDatastore) ds; //映射字段添加对应的自定义注释的注册 MappedField.interestingAnnotations.add(Lowercase.class); //映射mapper中添加相关的拦截器 morphia.getMapper().addInterceptor(new ToLowercaseHelper()); //设置映射的类 morphia.map(MorphiaInfo.class); //保存一个mongo对象 MorphiaInfo u = new MorphiaInfo(); u.setVersion("Morphia V1.0"); u.setMorphiaName("MorphiaName"); ds.save(u); //查找一个mongo对象MorphiaInfo uScott = ds.find(MorphiaInfo.class).disableValidation().filter("morphiaName_lowercase", u.getMorphiaName().toLowerCase()).get(); System.out.println("uScott="+uScott.getMorphiaName()); } catch (Exception e) {e.printStackTrace();}}}??
?
二：自定义转换器的使用
?
?? ??? 在Morphia中为什么各种数据库可以自由转换为Java对象呢？主要采用转换器机制实现实现字符串和Java对象之间的转换，转换器类需要实现TypeConvertor，如下：
?
public class FooConverter extends TypeConverter implements SimpleValueConverter
?
下面讲解转换器的使用：
package com.easyway.mongodb.morphia.converter;import com.google.code.morphia.annotations.Entity;import com.google.code.morphia.annotations.Id;/** * * @Title: TODO * @Description: 实现TODO * @Copyright:Copyright (c) 2011 * @Company:易程科技股份有限公司 * @Date:2012-3-4 * @author * @version 1.0 */@Entity(noClassnameStored=false,value="animail")public class Animail {@Idprivate String id;public String getId() {return id;}public void setId(String id) {this.id = id;}}?package com.easyway.mongodb.morphia.converter;import java.util.HashMap;import java.util.Map;import com.google.code.morphia.annotations.Embedded;import com.google.code.morphia.annotations.Entity;/** * * @Title: TODO * @Description: 实现TODO * @Copyright:Copyright (c) 2011 * @Company:易程科技股份有限公司 * @Date:2012-3-4 * @author * @version 1.0 */@Entity(noClassnameStored=false,value="animail")public class Dog extends Animail{private static final long serialVersionUID = 1L;@EmbeddedMap<String, Foo> foo = new HashMap<String, Foo>();}?package com.easyway.mongodb.morphia.converter;import net.sf.json.JSONObject;/** * * @Title: TODO * @Description: 实现TODO * @Copyright:Copyright (c) 2011 * @Company:易程科技股份有限公司 * @Date:2012-3-4 * @author * @version 1.0 */public class Foo {private String name;private String email;Foo(){}public Foo(String name,String email) {this.name = name;this.email=email;}public String getName() {return name;}public void setName(String name) {this.name = name;}public String getEmail() {return email;}public void setEmail(String email) {this.email = email;}@Overridepublic String toString() {return JSONObject.fromObject(this).toString();}}?
转换器类如下：
package com.easyway.mongodb.morphia.converter;import net.sf.json.JSONObject;import com.google.code.morphia.converters.SimpleValueConverter;import com.google.code.morphia.converters.TypeConverter;import com.google.code.morphia.mapping.MappedField;import com.google.code.morphia.mapping.MappingException;/** * * @Title: TODO * @Description: 实现TODO * @Copyright:Copyright (c) 2011 * @Company:易程科技股份有限公司 * @Date:2012-3-4 * @author * @version 1.0 */public class FooConverter extends TypeConverter implements SimpleValueConverter {public boolean done;public FooConverter() {super(Foo.class);}/** * */@Overridepublic Object decode(Class targetClass, Object fromDBObject, MappedField mf)throws MappingException {if(fromDBObject==null){return null;}JSONObject jsonObject=JSONObject.fromObject(fromDBObject);return JSONObject.toBean(jsonObject, targetClass);}@Overridepublic Object encode(Object value, MappedField optionalExtraInfo) {done = true;return JSONObject.fromObject(value).toString();}public boolean didConversion() {return done;}}?package com.easyway.mongodb.morphia.converter;import java.util.LinkedList;import java.util.List;import com.google.code.morphia.annotations.Embedded;import com.google.code.morphia.annotations.Entity;/** * * @Title: TODO * @Description: 实现TODO * @Copyright:Copyright (c) 2011 * @Company:易程科技股份有限公司 * @Date:2012-3-4 * @author * @version 1.0 */@Entity(noClassnameStored=false,value="animail")public class Pig extends Animail{private static final long serialVersionUID = 1L;@EmbeddedList<Foo> foo = new LinkedList<Foo>();}?
测试如下：
package com.easyway.mongodb.morphia.converter;import java.net.UnknownHostException;import com.google.code.morphia.AdvancedDatastore;import com.google.code.morphia.Datastore;import com.google.code.morphia.Morphia;import com.mongodb.DB;import com.mongodb.Mongo;import com.mongodb.MongoException;/** * * @Title: TODO * @Description: 实现TODO * @Copyright:Copyright (c) 2011 * @Company:易程科技股份有限公司 * @Date:2012-3-4 * @author * @version 1.0 */public class FooConverterApp { public static void main(String[] args) throws UnknownHostException, MongoException { Morphia morphia = new Morphia(); Mongo mongo = new Mongo("localhost"); DB db= mongo.getDB("morphia_test"); Datastore ds = morphia.createDatastore(mongo, db.getName()); AdvancedDatastore ads = (AdvancedDatastore) ds; morphia.map(Pig.class).map(Dog.class).map(Animail.class); FooConverter fc=new FooConverter(); //morphia.getMapper().getConverters().addConverter(fc); Dog e = new Dog();e.foo.put("bar",new Foo("bar"," a bar"));e.foo.put("big",new Foo("dog","a dog"));ds.save(e);System.out.println(e.foo.get("bar").toString());Pig pig=new Pig();pig.foo.add(new Foo("a","b"));pig.foo.add(new Foo("b","c"));ds.save(pig);} }??
?