一 【起源】
开始是因为对Spring的事务管理不太了解,想通过做一个小的CRUD demo来加深理解的。在做的过程中费尽周折花了不少力气,重要的是也有所收获。
事务管理主要是Spring声明式的 aop:config配置方式
二 【结构及用到的jar包】
jar包太多,不一一列举
三 【配置】
3.1 web.xml
3.2 Spring 相关配置
3.2.1 applicationContext.xml
数据库的用户名 密码 地址是配置在这个文件里的。
datasource用了两种配置方式 jdbc 以及 proxool
在这里引用下网上对连接池的评论
目前常用的连接池有:C3P0、DBCP、Proxool
网上的评价是:
C3P0比较耗费资源,效率方面可能要低一点。
DBCP在实践中存在BUG,在某些种情会产生很多空连接不能释放,Hibernate3.0已经放弃了对其的支持。
Proxool的负面评价较少,现在比较推荐它,而且它还提供即时监控连接池状态的功能,便于发现连接泄漏的情况。
3.2.2 Spring MVC 配置
spring-servlet.xml
图:
3.3 Hibernate配置
hibernate.cfg.xml
可见在这个文件里已无数据库 用户名 密码 地址 的配置了
四 【Service层】
接口类IService
接口实现类 MyServiceImp.java
主要的想法是用原生Sql而不是Hibernate sql,然后用Spring的事务管理去处理提交 回滚的操作
五 【Controller】
package cn.transaction.controller; import java.io.IOException; import java.util.ArrayList; import java.util.List; import javax.annotation.Resource; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import net.sf.json.JSONObject; import org.springframework.stereotype.Controller; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RequestMethod; import org.springframework.web.servlet.ModelAndView; import cn.transaction.domain.User; import cn.transaction.service.IService; @Controller @RequestMapping("/crud.do") public class CrudDemoController { @Resource(name="service") private IService service; private String errorPage; public IService getService() { return service; } public void setService(IService service) { this.service = service; } public String getErrorPage() { return errorPage; } public void setErrorPage(String errorPage) { this.errorPage = errorPage; } @RequestMapping(method = RequestMethod.GET) public ModelAndView list(HttpServletRequest request, HttpServletResponse response){ ModelAndView view = null; List list = new ArrayList(); try{ list = service.listUser(); view = new ModelAndView("/register"); request.setAttribute("list", list); }catch (Exception e) { // TODO: handle exception e.printStackTrace(); request.setAttribute("error", "系统错误!"); request.setAttribute("exception", e); } return view; } @RequestMapping(params = "method=listUserById") public ModelAndView listUserById(HttpServletRequest request, HttpServletResponse response){ ModelAndView view = null; List list = new ArrayList(); String idStr = request.getParameter("id"); int userId = Integer.parseInt(idStr); try{ list = service.listUserById(userId); view = new ModelAndView("/register"); request.setAttribute("list", list); }catch (Exception e) { // TODO: handle exception e.printStackTrace(); request.setAttribute("error", "系统错误!"); request.setAttribute("exception", e); } return view; } @RequestMapping(params = "method=delete") public ModelAndView delete(HttpServletRequest request, HttpServletResponse response){ ModelAndView view = null; List list = new ArrayList(); String idStr = request.getParameter("id"); int userId = Integer.parseInt(idStr); try{ service.deleteUser(userId); list = service.listUser(); view = new ModelAndView("/register"); request.setAttribute("list", list); }catch (Exception e) { // TODO: handle exception e.printStackTrace(); request.setAttribute("error", "系统错误!"); request.setAttribute("exception", e); } return view; } @RequestMapping(params = "method=insert") public ModelAndView insert(HttpServletRequest request, HttpServletResponse response)throws IOException{ ModelAndView view = null; List list = new ArrayList(); String json = request.getParameter("user"); /* BufferedReader br = new BufferedReader(new InputStreamReader( (ServletInputStream) request.getInputStream())); String line = null; StringBuilder sb = new StringBuilder(); while ((line = br.readLine()) != null) { sb.append(line); } */ JSONObject jsonObj = JSONObject.fromObject(json.toString()); User user = (User)JSONObject.toBean(jsonObj, User.class); System.out.println("name==>"+user.getUsername()); try{ service.insertUser(user); list = service.listUser(); view = new ModelAndView("/register"); request.setAttribute("list", list); }catch (Exception e) { // TODO: handle exception e.printStackTrace(); request.setAttribute("error", "系统错误!"); request.setAttribute("exception", e); } return view; } @RequestMapping(params = "method=edit") public ModelAndView edit(HttpServletRequest request, HttpServletResponse response){ ModelAndView view = null; List list = new ArrayList(); String json = request.getParameter("user"); JSONObject jsonObj = JSONObject.fromObject(json.toString()); User user = (User)JSONObject.toBean(jsonObj, User.class); System.out.println("idss==>"+user.getUserid()); try{ service.updateUser(user); list = service.listUser(); view = new ModelAndView("/register"); request.setAttribute("list", list); }catch (Exception e) { // TODO: handle exception e.printStackTrace(); request.setAttribute("error", "系统错误!"); request.setAttribute("exception", e); } return view; } //点击编辑或新增按钮转向的页面 @RequestMapping(params = "method=insertOrUpdate") public ModelAndView insertOrUpdate(HttpServletRequest request, HttpServletResponse response){ ModelAndView view = null; List list = new ArrayList(); String idStr = request.getParameter("id"); int userId = -1; User user = null; if (null != idStr && !"".equals(idStr) ){ userId = Integer.parseInt(idStr); }else{ return null; } try{ if (userId != -1) user = service.listUserById(userId).get(0); view = new ModelAndView("/userinfo"); if (null != user) request.setAttribute("user", user); }catch (Exception e) { // TODO: handle exception e.printStackTrace(); request.setAttribute("error", "系统错误!"); request.setAttribute("exception", e); } return view; } }
六 【View 层】
列表界面 register.jsp
编辑界面 userinfo.jsp
这个页面是把User 作为一个json对象 整个传递给了后台。
后台对json的接收
七 【问题及解决】
1.
java.lang.ClassNotFoundException: org.springframework.web.context.ContextLoaderServlet
是由于我的配置文件还是按照老的spring2.x的方式配置的,后来根据reference和网上的资料按spring3.1的方法重新配置了web.xml applicationContext.xml, 问题解决
参考:http://blog.csdn.net/xingfuzhijianxia/article/details/6433918
2.
UnknownUnwrapTypeException: Cannot unwrap to requested type [javax.sql.DataSource]
错误信息:
……
onManager'; nested exception is org.springframework.beans.factory.BeanCreationEx
ception: Error creating bean with name 'txManager' defined in ServletContext res
ource [/WEB-INF/applicationContext.xml]: Invocation of init method failed; neste
d exception is org.hibernate.service.UnknownUnwrapTypeException: Cannot unwrap t
o requested type [javax.sql.DataSource]
这个错误是一开始我把datasource 也就是数据库的用户名 密码 地址配在Hibernate的配置文件里了。
applicationContext里面没有配datasource引起的。后来查阅资料得知Spring的配置文件里必须有datasource
才行,不然就会报这种错误。
3.
json错误:
net.sf.json.JSONException: A JSONObject text must begin with '{' at character 1 of object Object
错误原因是我jsp页面中生成的json字符串格式问题
解决参考:
http://bbs.csdn.net/topics/350138016
4.
org.hibernate.exception.SQLGrammarException: ORA-01747: user.table.column, table.column
这个问题是由于Sql中的查询字段与数据库表中的系统关键字冲突,或者
是因为sql语句写的有问题,把sql 拿到sqlplus中验证即可
八 【鸣谢】
本文编撰过程中参阅了以下内容,特表示感谢:
http://blog.csdn.net/xingfuzhijianxia/article/details/6433918
http://bbs.csdn.net/topics/350138016
http://www.iteye.com/topic/615413
http://www.iteye.com/topic/1120924