java架构搭建（二）--常用api封装

淩亂°似流年 2022-03-30 11:47 177阅读 0赞

此篇接上篇（java架构搭建（一））继续   http://blog.csdn.net/lushuaiyin/article/details/8588203

到此按照步骤应该测试ssh的整合是否可用

## 一，HibernateTemplate的封装 ##

为什么要用HibernateTemplate？因为它已经帮我们封装好了很多方法（在spring中）。我们不必直接调用sessionFactory，再调用事务transAction，再调用session...

我们使用hibernate无非就是操作数据库，就是增删改查。这里封装好了，我们直接用就很方便了。在此我再进一步封装，以便于我们自己理解和使用，

或者简化它，或者完善它。对HibernateTemplate的封装，我们并不直接继承org.springframework.orm.hibernate3.HibernateTemplate，

而是继承org.springframework.orm.hibernate3.support.HibernateDaoSupport。为什么呢？我们看看源码：

/*jadclipse*/// Decompiled by Jad v1.5.8g. Copyright 2001 Pavel Kouznetsov.
    
    package org.springframework.orm.hibernate3.support;
    
    import org.hibernate.*;
    import org.springframework.dao.DataAccessException;
    import org.springframework.dao.DataAccessResourceFailureException;
    import org.springframework.dao.support.DaoSupport;
    import org.springframework.orm.hibernate3.HibernateTemplate;
    import org.springframework.orm.hibernate3.SessionFactoryUtils;
    
    public abstract class HibernateDaoSupport extends DaoSupport
    {
    
        public HibernateDaoSupport()
        {
        }
    
        public final void setSessionFactory(SessionFactory sessionFactory)
        {
            if(hibernateTemplate == null || sessionFactory != hibernateTemplate.getSessionFactory())
                hibernateTemplate = createHibernateTemplate(sessionFactory);
        }
    
        protected HibernateTemplate createHibernateTemplate(SessionFactory sessionFactory)
        {
            return new HibernateTemplate(sessionFactory);
        }
    
        public final SessionFactory getSessionFactory()
        {
            return hibernateTemplate == null ? null : hibernateTemplate.getSessionFactory();
        }
    
        public final void setHibernateTemplate(HibernateTemplate hibernateTemplate)
        {
            this.hibernateTemplate = hibernateTemplate;
        }
    
        public final HibernateTemplate getHibernateTemplate()
        {
            return hibernateTemplate;
        }
    
        protected final void checkDaoConfig()
        {
            if(hibernateTemplate == null)
                throw new IllegalArgumentException("'sessionFactory' or 'hibernateTemplate' is required");
            else
                return;
        }
    
        protected final Session getSession()
            throws DataAccessResourceFailureException, IllegalStateException
        {
            return getSession(hibernateTemplate.isAllowCreate());
        }
    
        protected final Session getSession(boolean allowCreate)
            throws DataAccessResourceFailureException, IllegalStateException
        {
            return allowCreate ? SessionFactoryUtils.getSession(getSessionFactory(), hibernateTemplate.getEntityInterceptor(), hibernateTemplate.getJdbcExceptionTranslator()) : SessionFactoryUtils.getSession(getSessionFactory(), false);
        }
    
        protected final DataAccessException convertHibernateAccessException(HibernateException ex)
        {
            return hibernateTemplate.convertHibernateAccessException(ex);
        }
    
        protected final void releaseSession(Session session)
        {
            SessionFactoryUtils.releaseSession(session, getSessionFactory());
        }
    
        private HibernateTemplate hibernateTemplate;
    }
    
    
    /*
    	DECOMPILATION REPORT
    
    	Decompiled from: D:\ChinaDevelopmentBankJBPM\workSpace\frame\webapp\WEB-INF\lib\spring-orm-3.0.3.RELEASE.jar
    	Total time: 139 ms
    	Jad reported messages/errors:
    	Exit status: 0
    	Caught exceptions:
    */

其中方法 public final void setSessionFactory(SessionFactory sessionFactory) 是为了注入sessionFactory；

public final void setHibernateTemplate(HibernateTemplate hibernateTemplate)是为了注入hibernateTemplate；

我们在applicationContext.xml中配置好后，就可以注入。要使用这些对象只要用get方法即可获取到。

而org.springframework.orm.hibernate3.HibernateTemplate类主要实现了数据库的操作，里面的方法很多。

比如public void saveOrUpdate(final Object entity)；public Serializable save(final Object entity)；

public void delete(Object entity)；其中有个方法比较重要，因为和事务有关：

public Object execute(HibernateCallback action)
            throws DataAccessException
        {
            return doExecute(action, false, false);
        }

我进行的封装MyHibernateDao

package org.base;
    
    import java.io.Serializable;
    import java.sql.SQLException;
    import java.util.List;
    
    import org.hibernate.HibernateException;
    import org.hibernate.Query;
    import org.hibernate.SQLQuery;
    import org.hibernate.Session;
    import org.hibernate.SessionFactory;
    import org.springframework.dao.DataAccessException;
    import org.springframework.orm.hibernate3.HibernateCallback;
    import org.springframework.orm.hibernate3.HibernateTemplate;
    import org.springframework.orm.hibernate3.support.HibernateDaoSupport;
    
    public abstract class MyHibernateDao extends HibernateDaoSupport {
    	
    	protected final HibernateTemplate createHibernateTemplate(SessionFactory sessionFactory) {
    		return new HibernateTemplate(sessionFactory);
    	}
    	
        /以下是对原生SQL语句的封装///
    	
    	//执行insert,update,delete语句
    	public void executeSql(final String sql) {
    		this.getHibernateTemplate().execute(
    				new HibernateCallback<Object>(){
    					public Object doInHibernate(Session session) throws HibernateException {
    						session.createSQLQuery(sql).executeUpdate();
    						return null;
    					}
    				}		
    		);
    	}
    	//执行select语句
    	public List querySql(final String sql) {    
    	    return (List) this.getHibernateTemplate().execute(
    	    		new HibernateCallback<Object>() {    
    		            public Object doInHibernate(Session session) throws HibernateException {    
    		                   try {    
    		                       SQLQuery query = session.createSQLQuery(sql);
    		                       return query.list();    
    		                   } catch (Exception e) {
    		                	   return null;
    		                   }    
    		            }    
    		        }		
    	    );    
    	}
    	
    	
    	/以下是对HQL语句的封装///
    	
    	
    	//执行insert,update,delete语句
    	public int executeHql(final String hql) throws DataAccessException {
    		return ((Integer)this.getHibernateTemplate().execute(
    				new HibernateCallback<Object>(){
    					public Object doInHibernate(Session session) throws HibernateException {
    						Query query = session.createQuery(hql);
    						return new Integer(query.executeUpdate());
    					}
    				}		
    		)).intValue();
    	}
    	
    	//执行select语句
    	public List queryListHql(final String hql) throws DataAccessException {
    		return (List)this.getHibernateTemplate().execute(
    				new HibernateCallback<Object>(){
    					public Object doInHibernate(Session session) throws HibernateException, SQLException {
    						Query query = session.createQuery(hql);
    						return query.list();
    					}
    				}		
    		);
    	}
    	
    	
    	public void saveOrUpdateHql(Object obj) {
           getHibernateTemplate().saveOrUpdate(obj);
        }
    	
    	public Serializable saveHql(Object obj) {
    	   return getHibernateTemplate().save(obj);
    	}
    	
    	public void deleteHql(Object obj) {
        	getHibernateTemplate().delete(obj);
        }
    	
    	
    }

只是简单进行了常用封装，对于HibernateTemplate中更多有用的方法还没封装。

这样在操作数据库的service层，我们就可以继承这个MyHibernateDao，并使用里面的方法了。

## 二，对BaseAction的封装。 ##

大多数action层不会直接继承ActionSupport（在学习struts2时我们直接继承这个ActionSupport）。

一般情况下，在业务层就是action里，我们会有一些常用的方法，比如比session的操作，登录用户信息的获取等，

这些常用的方法如果每次用到都重新写一遍那真是代码太过冗余，而且也不好维护，把这些方法封装在BaseAction里，

我们只需要把业务的action继承这个BaseAction就可以使用这些方法了。

MyBaseAction

package org.base;
    
    import java.io.PrintWriter;
    
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import javax.servlet.http.HttpSession;
    
    import org.apache.struts2.ServletActionContext;
    
    import com.opensymphony.xwork2.ActionContext;
    import com.opensymphony.xwork2.ActionSupport;
    
    public class MyBaseAction  extends ActionSupport {
    	
    	private static final long serialVersionUID = 1L;
    	public ActionContext getActionContext() throws Exception{
    		return ActionContext.getContext();
    	}
    	
    	public HttpSession getHttpSession() throws Exception{
    		ActionContext ctx = ActionContext.getContext();
    		HttpServletRequest request  = (HttpServletRequest) ctx.get(ServletActionContext.HTTP_REQUEST);
    		return request.getSession();
    	}
    	
    	public HttpServletRequest getHttpServletRequest() throws Exception{
    		ActionContext ctx = ActionContext.getContext();
    		HttpServletRequest request  = (HttpServletRequest) ctx.get(ServletActionContext.HTTP_REQUEST);
    		return request;
    	}
    	
    	public HttpServletResponse getHttpServletResponse() throws Exception{
    		ActionContext ctx = ActionContext.getContext();
    		HttpServletResponse response = (HttpServletResponse) ctx.get(ServletActionContext.HTTP_RESPONSE);
    		return response;
    	}
    	
    	public PrintWriter getPrintWriter() throws Exception{
    		ActionContext ctx = ActionContext.getContext();
    		HttpServletResponse response = (HttpServletResponse) ctx.get(ServletActionContext.HTTP_RESPONSE); 
    		PrintWriter out = response.getWriter();
    		return out;
    	}
    	/ActionContext取值放值//
    	
    	public Object getValueFromActionContext(String key) throws Exception{
    		ActionContext ac = ActionContext.getContext();
    		if(key==null||key.trim().equals("")){
    			return null;
    		}else{
    			return ac.get(key.trim());
    		}
    	}
    	public void setValueToActionContext(String key,Object obj) throws Exception{
    		ActionContext ac = ActionContext.getContext();
    		if(key==null||key.trim().equals("")){
    		}else{
    			ac.put(key.trim(), obj);
    		}
    	}
    	
        /HttpSession取值放值//
    	public Object getValueFromSession(String key) throws Exception{
    		ActionContext ctx = ActionContext.getContext();
    		HttpServletRequest request  = (HttpServletRequest) ctx.get(ServletActionContext.HTTP_REQUEST); 
    		HttpSession session=request.getSession();
    		if(key==null||key.trim().equals("")){
    			return null;
    		}else{
    			return session.getAttribute(key.trim());
    		}
    	}
    	public void setValueToSession(String key,Object obj) throws Exception{
    		ActionContext ctx = ActionContext.getContext();
    		HttpServletRequest request  = (HttpServletRequest) ctx.get(ServletActionContext.HTTP_REQUEST); 
    		HttpSession session=request.getSession();
    		if(key==null||key.trim().equals("")){
    		}else{
    			session.setAttribute(key.trim(), obj);
    		}
    	}
    	
    	/HttpServletRequest取值放值//
    	public Object getValueFromRequest(String key) throws Exception{
    		ActionContext ctx = ActionContext.getContext();
    		HttpServletRequest request  = (HttpServletRequest) ctx.get(ServletActionContext.HTTP_REQUEST); 
    		if(key==null||key.trim().equals("")){
    			return null;
    		}else{
    			return request.getAttribute(key.trim());
    		}
    	}
    	public void setValueToRequest(String key,Object obj) throws Exception{
    		ActionContext ctx = ActionContext.getContext();
    		HttpServletRequest request  = (HttpServletRequest) ctx.get(ServletActionContext.HTTP_REQUEST); 
    		if(key==null||key.trim().equals("")){
    		}else{
    			request.setAttribute(key.trim(), obj);
    		}
    	}
    	
    }

这里我只封装了常用的session，request取值放值。

测试功能模块，代码过多，还是另起一篇吧。