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SSH Unit05

热度：54   发布时间：2023-12-11 14:56:44.0

SSH

整合开发

自定义异常处理

重新异常处理方法即可实现自定义异常处理:

  1. 重写异常处理方法 UserAction

    @Override
public String handleException(Exception e) {if(e instanceof UserNotFoundException){jsonResult = new JsonResult(2, e);}else if(e instanceof PasswordException){jsonResult = new JsonResult(3, e);}else if(e instanceof UserNameException){jsonResult = new JsonResult(4, e);}else {jsonResult = new JsonResult(e);}return JSON;
}

笔记本列表功能

  1. 映射笔记本实体到数据库表 Notebook.hbm.xml

    <?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN""http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<hibernate-mapping><class name="cn.tedu.note.entity.Notebook"table="cn_notebook"><id name="id" column="cn_notebook_id"></id><property name="name" column="cn_notebook_name"></property><property name="typeId" column="cn_notebook_type_id"></property><property name="userId" column="cn_user_id"></property><property name="desc" column="cn_notebook_desc"></property><property name="createtime" column="cn_notebook_createtime"type="java.sql.Timestamp"></property> </class> 
</hibernate-mapping>

  2. 更新配置文件 spring-hbm.xml:

    <property name="mappingLocations"><list><value>classpath:hbm/User.hbm.xml</value><value>classpath:hbm/Notebook.hbm.xml</value></list>
</property>

  3. 实现 NotebookDaoImpl

    @Repository("notebookDao")
public class NotebookDaoImpl implements NotebookDao {@Resourceprivate HibernateTemplate hibernateTemplate;public List<Map<String, Object>> findNotebooksByUserId(String userId) {final String hql="select new map(id as id, name as name) "+"from Notebook "+"where userId=? "+"order by createtime desc";List<Map<String, Object>> list= hibernateTemplate.find(hql, userId);return list;}public int countNotebookById( String notebookId) {//sql:// select count(*) // from cn_notebook// where cn_notebook_id=?//hql:// select count(*) // from Notebook// where id=?String hql = "select count(*) "+ "from Notebook where id=?";List<Number> list=hibernateTemplate.find(hql, notebookId);return list.isEmpty()? 0: list.get(0).intValue();}public List<Map<String, Object>> findNotebooksByPage(final String userId, final int start, final int pageSize, final String table) {//sql: select cn_notebook_id, cn_notebook_name //  from cn_notebook //  where cn_user_id=?//  order by cn_notebook_createtime desc//HQL://  select new map(id as id, name as name)//  from Notebook//  where userId=?//  order by createtime descfinal String hql="select new map(id as id, name as name) "+"from Notebook "+"where userId=? "+"order by createtime desc";List<Map<String, Object>> list=hibernateTemplate.execute(new HibernateCallback<List<Map<String, Object>>>() { public List<Map<String, Object>> doInHibernate(Session session) throws HibernateException, SQLException {//利用session创建查询对象Query query=session.createQuery(hql);//绑定 查询参数query.setString(0, userId);//绑定分页参数:query.setFirstResult(start);query.setMaxResults(pageSize);//query.list() 执行查询//返回查询结果return query.list();}});return list;}}

  4. 单元测试: 对持久层和业务层进行回归性测试

    ...

  5. 创建控制器 NotebookAction

    @Controller
@Scope("prototype")
public class NotebookAction extends AbstractAction {@Resourceprivate NotebookService notebookService;private String userId;private Integer page;public String getUserId() {return userId;}public void setUserId(String userId) {this.userId = userId;}public Integer getPage() {return page;}public void setPage(Integer page) {this.page = page;}public String page(){List<Map<String, Object>> list=notebookService.listNotebooks(userId, page);jsonResult = new JsonResult(list);return JSON;}public String list(){List<Map<String, Object>> list=notebookService.listNotebooks(userId);jsonResult = new JsonResult(list);return JSON;}}

  6. 配置控制器:

    配置文件结构:

这里写图片描述

> 配置文件内容重构: struts.xml<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE struts PUBLIC"-//Apache Software Foundation//DTD Struts Configuration 2.3//EN""http://struts.apache.org/dtds/struts-2.3.dtd"><struts><!-- 修改请求扩展名 action改为do --><constant name="struts.action.extension" value="do"></constant><package name="basepkg" extends="json-default"><interceptors><interceptor name="demo" class="myInterceptor"/><interceptor name="execInte" class="exceptionInterceptor"/><interceptor-stack name="noteStack"><interceptor-ref name="defaultStack"/><interceptor-ref name="execInte"></interceptor-ref></interceptor-stack><interceptor-stack name="demoStack"><interceptor-ref name="defaultStack"/><interceptor-ref name="demo"></interceptor-ref></interceptor-stack></interceptors><default-interceptor-ref name="noteStack"/><global-results><result name="json" type="json"><param name="root">jsonResult</param></result></global-results></package><package name="user" namespace="/user" extends="basepkg"><action name="login" class="userAction" method="login"/><action name="regist" class="userAction" method="regist"/></package><package name="notebook" extends="basepkg"namespace="/notebook"><action name="page" class="notebookAction"method="page"/><action name="list" class="notebookAction"method="list"/></package></struts>
  1. 对控制器进行测试, 对页面功能进行测试

Hibernate

Hibernate的结构:

这里写图片描述

Session 提供了CRUD 功能

  • Sesison.get(id)
    • 根据ID从数据库中获取对象, 如果找不到返回null
  • Session.load(id)
    • 根据ID从数据库中获取对象, 如果找不到抛异常
  • Session.save()
    • 将新对象添加到数据库
  • Session.update()
    • 将对象信息保存到数据库
  • Session.delete()
    • 将对象的信息从数据库中删除
  • Session.clear()
    • 清空Session一级缓存
  • Session.evict(对象)
    • 将一个对象从Session缓存中清除

Hibernate 持久化对象生存周期状态管理

这里写图片描述

Java Bean == POJO

案例:

public class HibernateTest extends BaseTest {SessionFactory factory;Session session;@Before public void initSession(){factory = ctx.getBean("sessionFactory",SessionFactory.class);session = factory.openSession();}@Afterpublic void destory(){session.close();factory.close();}@Testpublic void testSessionFactory(){//Spring 简化了 Session Factory 的关联SessionFactory factory =ctx.getBean("sessionFactory",SessionFactory.class);//利用SessionFactory创建SessionSession session = factory.openSession();System.out.println(session);session.close();System.out.println(factory);}@Testpublic void testSave(){Transaction tx=session.beginTransaction();//持久状态下,更改属性影响到数据库//user 对象 是临时状态的User user = new User("1234567", "熊大", "1234", "", "");//user成为持久状态session.save(user);user.setName("范传奇");user.setPassword("abcde");tx.commit();}@Testpublic void testGet(){Transaction tx=session.beginTransaction();//get返回对象是持久状态的User user = (User)session.get(User.class, "1234567");System.out.println(user);//更改持久创建对象的属性影响数据库user.setName("李洪鹤"); tx.commit();}@Testpublic void testEvict(){Transaction tx = session.beginTransaction();//get返回的对象是持久状态User user = (User)session.get(User.class, "1234567");System.out.println(user);//evict将对象清除 sessin缓存, 变成游离状态session.evict(user);//session.clear();user.setName("光头强");tx.commit();}@Testpublic void testUpdate(){Transaction tx = session.beginTransaction();//get返回的对象是持久状态User user = (User)session.get(User.class, "1234567");System.out.println(user);//evict将对象清除 sessin缓存, 变成游离状态session.evict(user);//session.clear();user.setName("光头强");//update 方法 将对象从游离状态改为持久状态session.update(user); tx.commit();}@Testpublic void testDelete(){Transaction tx = session.beginTransaction();//get返回的对象是持久状态User user = (User)session.get(User.class, "1234567");System.out.println(user);//delete方法将数据从数据库删除, // 对象user在内存中还有数据// 此时对象是临时状态的!session.delete(user); System.out.println(user);tx.commit();}@Test public void testLoad(){//get方法在没有数据时候, 返回nullUser user = (User)session.get(User.class, "1234567");System.out.println(user); //null//load方法在没有数据时候, 抛出异常User u = (User) session.load(User.class, "1234567");System.out.println(u); }@Testpublic void testQuery(){//执行HQL查询Transaction tx=session.beginTransaction();//sql: select * from cn_userString hql = "from User"; Query query=session.createQuery(hql);//list 执行返回一组数据的查询List<User> list = query.list();for (User user : list) {System.out.println(user);}tx.commit();}@Testpublic void testQuery2(){//执行带参数的SQL//sql: select * from cn_user //     where cn_user_name like ? String hql = "from User "+ "where name like ?"; Transaction tx = session.beginTransaction();Query query=session.createQuery(hql);//绑定查询参数query.setString(0, "%o%");//执行查询List<User> list=query.list();for (User user : list) {System.out.println(user);}tx.commit();}@Testpublic void testQuery3(){//按照名字绑定参数String hql = "from User "+ "where name like :name"; Transaction tx = session.beginTransaction();Query query=session.createQuery(hql);//绑定查询参数query.setString("name", "%o%");//执行查询List<User> list=query.list();for (User user : list) {System.out.println(user);}tx.commit();}@Testpublic void testQuery4(){//query 支持唯一结果查询Transaction tx = session.beginTransaction();String hql = "from User where name=?";Query query = session.createQuery(hql);query.setString(0, "demo");//uniqueResult 用于查找返回唯一的结果User user = (User)query.uniqueResult();System.out.println(user);user.setToken("123456"); tx.commit();}@Testpublic void testFindPerson(){String hql = "from Person";Query query = session.createQuery(hql);List<Person> list = query.list();for (Person person : list) {System.out.println(person); }}@Testpublic void testAddPerson(){Person person = new Person(null, "Wang");System.out.println(person);Transaction tx = session.beginTransaction();session.save(person);System.out.println(person);tx.commit();}@Testpublic void testFindComment(){String hql = "from Comment";Query query = session.createQuery(hql);List<Comment> list = query.list();for (Comment comment : list) {System.out.println(comment); }}@Testpublic void testFindPost(){String hql = "from Post";Query query = session.createQuery(hql);List<Post> list = query.list();for (Post p : list) {System.out.println(p); }}}

映射文件:

Person.hbm.xml

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN""http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<hibernate-mapping><class name="cn.tedu.note.entity.Person"table="p_person"><id name="id" column="id"><!-- 使用自增类型的主键生成器 --><generator class="identity"/></id><property name="name" column="name"/></class>
</hibernate-mapping>

Comment.hbm.xml

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN""http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<hibernate-mapping><class name="cn.tedu.note.entity.Comment"table="p_comment"><id name="id" column="id"><!-- 使用自增类型的主键生成器 --><generator class="identity"/></id><property name="title" column="title"/></class>
</hibernate-mapping>

Post.hbm.xml

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN""http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<hibernate-mapping><class name="cn.tedu.note.entity.Post"table="p_post"><id name="id" column="id"><!-- 使用自增类型的主键生成器 --><generator class="identity"/></id><property name="title" column="title"/><!-- 多个post对应一个person --><!-- 其中: 属性是person, 属性的类型是Person属性对应的表格列是 person_id --><many-to-one name="person" class="cn.tedu.note.entity.Person"column="person_id" ></many-to-one><set name="comments" ><!-- p_comment 表中的 外键列 post_id--><key column="post_id"></key><!-- 当前一个(one)帖子对应多个(many)回复 --><one-to-many class="cn.tedu.note.entity.Comment"/></set></class>
</hibernate-mapping>

单例模式

模式: 解决问题的固定套路

单例: 在软件中永远唯一的对象个体.

单例模式: 解决 在软件中永远唯一的对象个体 固定套路

注意: Spring 中的Bean默认情况下是 “单例”的, 但是不能称为单例模式!!

饿汉式:

//"饿汉式" 立即加载模式
class Girl{private static Girl instance = new Girl();private Girl(){}public static Girl getInstance() {return instance;} 
}

懒汉式

//"懒汉式" 按需加载
class Boy{private static Boy instance;private Boy(){}public synchronized static Boy getInstance() {if(instance == null){instance = new Boy();}return instance;}
}
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