A Struts interview question

The question is: There are two tables with two fields for the news category table: nid (pk) sort there is a news content table with three fields cid (pk) nid (fk) title content requires you to select a news category using the drop-down list box and display the news titles of this category (displayed on the current page). I implemented it using Struts2 + Hibernate3.2 + JPA. database Script: create database if not exists news; drop table if exists newssort; create table newssort (nid int primary key AUTO_INCREMENT, sort varchar (50); drop table if exists news; create table news (cid int primary key AUTO_INCREMENT, title varchar (50) not null, content varchar (500) not null, nid int null); insert into newssort values (null, 'enter'); insert into newssort values (null, 'data'); insert into news values (null, 'good thing', 'good things are connected to Haha ', 1); insert into news values (null, 'bad thing ', 'bad thing', 1); insert into news values (null, 'Love is what ', 'Love is what, don't know yet', 2); insert into news values (null, 'who', 'test content', 2); select * from news; select * from newssort; two VO classes: News. java: package co M. vo; import java. io. serializable; import javax. persistence. entity; import javax. persistence. generatedValue; import javax. persistence. generationType; import javax. persistence. id; import javax. persistence. table; @ SuppressWarnings ("serial") @ Entity @ Table (name = "news") public class News implements Serializable {private Integer cid; private String title; private String content; @ Id @ GeneratedValue (strategy = G EnerationType. AUTO) public Integer getCid () {return cid;} public void setCid (Integer cid) {this. cid = cid;} public String getTitle () {return title;} public void setTitle (String title) {this. title = title;} public String getContent () {return content;} public void setContent (String content) {this. content = content ;}} Newssort. java: package com. vo; import java. io. serializable; import java. u Til. arrayList; import java. util. list; import javax. persistence. entity; import javax. persistence. generatedValue; import javax. persistence. generationType; import javax. persistence. id; import javax. persistence. joinColumn; import javax. persistence. onetovel; import javax. persistence. table; import org. hibernate. annotations. lazyCollection; import org. hibernate. annotations. lazyCollectionOption; @ SuppressWarnings ("Serial") @ Entity @ Table (name = "newssort") public class Newssort implements Serializable {private Integer nid; private String sort; private List <News> news = new ArrayList <News> (); @ onetoworkflow @ JoinColumn (name = "nid") @ LazyCollection (LazyCollectionOption. FALSE) public List <News> getNews () {return news;} public void setNews (List <News> news) {this. news = news;} @ Id @ GeneratedValue (strategy = Genera TionType. AUTO) public Integer getNid () {return nid;} public void setNid (Integer nid) {this. nid = nid;} public String getSort () {return sort;} public void setSort (String sort) {this. sort = sort;} write a test class to test a persistent layer operation: package com. test; import java. util. iterator; import org. hibernate. session; import org. hibernate. cfg. annotationConfiguration; import org. junit. after; import org. junit. before; import com. Vo. news; import com. vo. newssort; public class Test {private Session session; @ Before public void setUp () {session = new AnnotationConfiguration (). configure (). buildSessionFactory (). openSession () ;}@ After public void tearDown () {session. close () ;}@ SuppressWarnings ("unchecked") @ org. junit. test public void testFind () {@ SuppressWarnings ("unused") // List <Newssort> newssort = session. createCriteria (Newssort. class ). list (); Newssort newssort = (Newssort) session. load (Newssort. class, 2); for (Iterator <News> I = newssort. getNews (). iterator (); I. hasNext ();) {String title = I. next (). getTitle (); System. out. println (title) ;}}write ActionNewsAction: package com. web. action; import java. util. list; import java. util. map; import org. hibernate. session; import org. hibernate. cfg. annotationConfiguration; import Com. opensymphony. xwork2.ActionContext; import com. opensymphony. xwork2.ActionSupport; import com. vo. news; import com. vo. newssort; @ SuppressWarnings ({"serial", "unchecked"}) public class NewsAction extends ActionSupport {private Session session; private Integer sortid; public Integer getSortid () {return sortid ;} public void setSortid (Integer sortid) {this. sortid = sortid;} public void init () {se Ssion = new AnnotationConfiguration (). configure (). buildSessionFactory (). openSession ();} public String findNewssort () {this. init (); List <Newssort> sorts = session. createCriteria (Newssort. class ). list (); Map request = (Map) ActionContext. getContext (). get ("request"); request. put ("sorts", sorts); session. close (); return SUCCESS;} public String findNews () {this. init (); System. out. println ("findNews" ); List <Newssort> sorts = session. createCriteria (Newssort. class ). list (); Newssort newssort = (Newssort) session. load (Newssort. class, sortid); List <News> news = newssort. getNews (); Map request = (Map) ActionContext. getContext (). get ("request"); request. put ("sorts", sorts); request. put ("news", news); session. close (); return SUCCESS ;}} hibernate. cfg. xml: <? Xml version = "1.0" encoding = "UTF-8"?> <! DOCTYPE hibernate-configuration PUBLIC "-// Hibernate/Hibernate Configuration DTD 3.0 // EN "" http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd "> <Hibernate-configuration> <session-factory> <property name =" dialect "> org. hibernate. dialect. mySQLDialect </property> <property name = "connection. driver_class "> com. mysql. jdbc. driver </property> <property name = "connection. url "> jdbc: mysql: // localhost: 3306/news </property> <property name =" connection. username "> root </property> <property name =" connection. password "> root </property> <property name =" show_ SQL "> tr Ue </property> <! -- Object class ing --> <mapping class = "com. vo. news "/> <mapping class =" com. vo. newssort "/> </session-factory>