【自虐】1.1加入JDBC完成增删改查

写的很差，有兴趣就跑跑项目吧，在附件中，文章可看性很低。

环境：win7 MyEclipse10 jdk1.6 tomcat7 SpringMVC2.5 MySQL

目标：CRUD

 

从前文http://340413629-qq-com.iteye.com/blog/2032793修改而来，目的是使用增加数据库的操作

 

加入jdbcUtil类封装取得连接和释放资源的操作

package cn.zinue100.util;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public final class JdbcUtils {
	private static final String url = "jdbc:mysql://localhost:3306/test";
	private static final String username = "root";
	private static final String password = "root";

	private JdbcUtils() {
	}

	static {
		try {
			Class.forName("com.mysql.jdbc.Driver");
		} catch (ClassNotFoundException e) {
			throw new ExceptionInInitializerError(e);
		}
	}

	public static Connection getConnection() throws SQLException {
		return DriverManager.getConnection(url, username, password);
	}

	public static void free(ResultSet resultSet, Statement statement,
			Connection connection) {
		try {
			if (resultSet != null)
				resultSet.close();
		} catch (SQLException e) {
			throw new ExceptionInInitializerError(e);
		} finally {
			try {
				if (statement != null)
					statement.close();
			} catch (SQLException e) {
				throw new ExceptionInInitializerError(e);
			} finally {
				try {
					if (connection != null)
						connection.close();
				} catch (SQLException e) {
					throw new ExceptionInInitializerError(e);
				}
			}
		}
	}
}

 这个类指使用了释放资源free方法，取得链接是通过配置连接池实现的在web-main.xml中多了如下配置，连接池是什么就不赘述了，这里没有配置最大连接数等等，只是做个样子

<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">

<property name="driverClassName" value="com.mysql.jdbc.Driver"/>

<property name="url" value="jdbc:mysql://localhost:3306/test"/>

<property name="username" value="root"/>

<property name="password" value="root"/>

</bean>

 

另外还多了<bean id="userDaoImpl" class="cn.zinue100.dao.jdbcImpl.UserDaoImpl" />这一配置

这是spring ioc 控制翻转，也叫依赖注入的体现，配置好这个bean之后在userConrol中加入变量

@Resource
private UserDao userDao;

 生成getter setter方法之后容器自动new dao

 

多加了三个jar包，在附件中有：

mysql-connector-java-5.1.27-bin.jar

commons-dbcp.jar

commons-pool.jar

其他的就不赘述了

主要是想学springmvc的跳转，我自己来总结一下：

贴出UserControl代买

package cn.zinue100.controller;

import java.io.File;
import java.io.IOException;
import java.util.LinkedHashMap;
import java.util.Map;

import javax.annotation.Resource;
import javax.servlet.http.HttpServletRequest;
import javax.validation.Valid;

import org.apache.commons.io.FileUtils;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.validation.BindingResult;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.SessionAttributes;
import org.springframework.web.multipart.MultipartFile;
import org.springframework.web.servlet.mvc.support.RedirectAttributes;

import cn.zinue100.dao.UserDao;
import cn.zinue100.vo.User;

@Controller
@RequestMapping(value = "/user")
@SessionAttributes(value = "loginUser")
public class UserController {

	@Resource
	private UserDao userDao;
	private User user;
	Map<String, User> users = new LinkedHashMap<String, User>();

	@RequestMapping(value = "/list.htm")
	public String list(Model model) {
		init(model, null);
		return "user/userlist";
	}

	@RequestMapping(value = "/add.htm", method = RequestMethod.GET)
	public String add(Model model) {
		model.addAttribute(new User());
		return "user/adduser";
	}

	@RequestMapping(value = "/add.htm", method = RequestMethod.POST)
	public String add(@Valid User user, BindingResult binding, Model model) {
		if (binding.hasErrors()) 
			return "user/adduser";
		userDao.addUser(user);
		init(model, user);
		return "redirect:/user/list.htm";
	}

	@RequestMapping(value = "/delete/{username}.htm", method = RequestMethod.GET)
	public String delete(@PathVariable String username) {
		user=new User();
		user.setUsername(username);
		userDao.deleteUser(user);
		return "redirect:/user/list.htm";
	}

	@RequestMapping(value = "/update/{username}.htm", method = RequestMethod.GET)
	public String update(@PathVariable String username, Model model) {
		User user = userDao.getUserByName(username);
		model.addAttribute("user", user);
		return "user/updateuser";
	}

	@RequestMapping(value = "/update/{username}.htm", method = RequestMethod.POST)
	public String update(@PathVariable String username, @Valid User user,BindingResult br) {
		if (br.hasErrors()) 
			return "/update/{username}.htm";
		userDao.updateUser(user);
		return "redirect:/user/list.htm";
	}

	@ResponseBody
	@RequestMapping(value = "/{username}.htm", params = "json")
	public User showJson(@PathVariable String username, Model model) {
		System.out.println("username:" + username);
		return null;
	}

	@RequestMapping(value = "/login.htm", method = RequestMethod.GET)
	public String login() {
		return "/user/login";
	}

	@RequestMapping(value = "/login.htm", method = RequestMethod.POST)
	public String login(String username, String password, Model model) {
		User user = userDao.getUserByName(username);
		if (user == null || user.getUsername() == null)
			throw new RuntimeException("用户名不存在!");
		if (user.getPassword() == null || !user.getPassword().equals(password))
			throw new RuntimeException("密码不正确");
		model.addAttribute("loginUser", user);
		return "redirect:/user/list.htm";
	}

	@ExceptionHandler(value = { RuntimeException.class })
	public String handlerException(Exception ex, HttpServletRequest req) {
		System.out.println("UserController.handlerException invok...");
		req.setAttribute("ex", ex);// 把异常放入request请求中
		return "error";// 转到error页面
	}

	@RequestMapping(value = "/redir.htm")
	public String redir(Model model, RedirectAttributes ra) {
		System.out.println("UserController.redir invok...");
		// model.addAttribute("movie", "海贼王");//使用这种方式在重定向是传递不了的
		ra.addFlashAttribute("movie", "海贼王");// 使用这种可以
		return "redirect:/user/list.htm";
	}

	@RequestMapping(value = "upload.htm", method = RequestMethod.GET)
	public String uploadPhoto() {
		System.out.println("UserController.uploadPhoto invok...");
		return "user/upload";
	}

	@RequestMapping(value = "upload.htm", method = RequestMethod.POST)
	public String uploadPhoto(MultipartFile photo, Model model,
			HttpServletRequest req) {
		System.out.println("UserController.init invok...");
		System.out.println(photo.getContentType());
		System.out.println(photo.getName());
		System.out.println(photo.getOriginalFilename());
		String realpath = req.getSession().getServletContext()
				.getRealPath("/upload/");
		System.out.println(realpath);
		try {
			FileUtils.copyInputStreamToFile(photo.getInputStream(), new File(
					realpath + "/" + photo.getOriginalFilename()));
		} catch (IOException e) {
			e.printStackTrace();
		}
		model.addAttribute("message", "上传成功");
		return "user/upload";
	}

	@RequestMapping(value = "uploads.htm", method = RequestMethod.POST)
	public String uploadPhoto(
			@RequestParam(required = false) MultipartFile[] photos,
			Model model, HttpServletRequest req) {
		System.out.println("UserController.init invok...");
		String realpath = req.getSession().getServletContext()
				.getRealPath("/upload/");
		try {
			for (MultipartFile photo : photos) {
				if (photo.isEmpty())
					continue;
				FileUtils.copyInputStreamToFile(photo.getInputStream(),
						new File(realpath + "/" + photo.getOriginalFilename()));
			}
		} catch (IOException e) {
			e.printStackTrace();
		}
		model.addAttribute("message", "上传成功");
		return "user/upload";
	}

	public UserDao getUserDao() {
		return userDao;
	}

	public void setUserDao(UserDao userDao) {
		this.userDao = userDao;
	}

	public User getUser() {
		return user;
	}

	public void setUser(User user) {
		this.user = user;
	}
	
	private void init(Model model, User user) {
		System.out.println("UserController.init invok...");
		Map<String, User> users = userDao.getUsers();
		model.addAttribute("users", users);
	}
}

 

 @RequestMapping(value = "/user")

就是说这个Control所有action都用user前缀

也就是说在一个静态页面href="user/login.htm就可以进这个action

@RequestMapping(value = "/login.htm", method = RequestMethod.GET)
public String login() {
	return "/user/login";
}

 

这个方法是从静态页面跳转的login页面的，我的jsp在user包下，名字叫login.jsp。很显然springmvc把jsp页面映射成别的了，只要名字匹配就可以跳转

在jsp页面有action="login.htm"于是跳转到了以下方法

@RequestMapping(value = "/login.htm", method = RequestMethod.POST)
public String login(String username, String password, Model model) {
	User user = userDao.getUserByName(username);
	if (user == null || user.getUsername() == null)
		throw new RuntimeException("用户名不存在!");
	if (user.getPassword() == null || !user.getPassword().equals(password))
		throw new RuntimeException("密码不正确");
	model.addAttribute("loginUser", user);
	return "redirect:/user/list.htm";
}

 

 单这个方法和前一个名字一样只是参数不同，那springmvc是怎么找过来对的呢？？我觉得是根据参数和jsp文档中input的name去匹配

	 	username:<input type="text" name="username"/><sf:errors path="username"/><br/>
	 	password:<input type="password" name="password"/><sf:errors path="password"/><br/>

 

 第三个参数model是什么呢，model在org.springframework.ui.Model;包中，所以我觉得model就是封装了页面信息，model放在哪里？？我觉得应该在session中

model.addAttribute("loginUser", user);
return "redirect:/user/list.htm";

 

 第二句代码转发到以htm结尾的url去了，很显然验证完用户名密码之后，要去初始化一览页面的信息，将跳转到control类的另一个方法

第一句往session中放了一个值，这个值在一览页面时这样显示的${loginUser.username}也就是说直接变量名key值，然后取属性，真是方便，目前不知道实现机制是什么，jstl还是ognl？？？

刚才说到跳转到list.htm，那贴出这个方法

 

	@RequestMapping(value = "/list.htm")
	public String list(Model model) {
		init(model, null);
		return "user/userlist";
	}

 初始化一览页面在很多地方用到，所以封装起来

 

private void init(Model model, User user) {
	Map<String, User> users = userDao.getUsers();
	model.addAttribute("users", users);
}

 我本来getUsers返回的是List，可是spring不允许我往model中放进list，必须放map。从这里可以看出model的实现机制 看一下我写的userlist页面

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%@page import="cn.zinue100.vo.User"%>
<%@page import="java.util.Map.Entry"%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>userlist</title>
</head>

<body>
	<a href="add.htm">Add</a>&nbsp;&nbsp;${loginUser.username
	}&nbsp;${movie }
	<br />
	<table border="1">
		<%
			Map<String, User> users = (Map<String, User>) request
					.getAttribute("users");
			if (users != null) {
				for (User user : users.values()) {
		%>
		<tr>
			<td><%=user%></td>
			<td>&nbsp;<a href="update/<%=user.getUsername()%>.htm">修改</a>
			</td>
			<td>&nbsp;<a href="delete/<%=user.getUsername()%>.htm">删除</a>
			</td>
		</tr>
		<%
			}
			}
		%>
	</table>
	<a href="login.htm">退出</a>
	<br />
</body>
</html>

 

另起一个话头

码农首先关心的是，怎么从control跳转到jsp，怎么从jsp跳转到control，怎么传值

从control跳转到jsp刚才说过了，在control中返回值是个字符串，把jsp文件名去掉后缀.jsp，前面加路径，放进这个字符串就行

jsp跳转到control，在action中配置，如果没配置，那就是跟自己文件名相同的action

 

那怎么传值呢？？

来看从一览页面去更新页面这个方法

@RequestMapping(value = "/update/{username}.htm", method = RequestMethod.GET)
public String update(@PathVariable String username, Model model) {
	User user = userDao.getUserByName(username);
	model.addAttribute("user", user);
	return "user/updateuser";
}

 

这是get方法的传值，直接在url上拼，因为注解了@PathVariable，所以取得时候直接用名称取，那post方法呢？？？

	@RequestMapping(value = "/update/{username}.htm", method = RequestMethod.POST)
	public String update(@PathVariable String username, @Valid User user,BindingResult br) {
		if (br.hasErrors()) 
			return "/update/{username}.htm";
		userDao.updateUser(user);
		return "redirect:/user/list.htm";
	}

 

 我没有把user这个对象传递过来，那spring怎么知道的？？因为这是我在类中定义的user变量，不知道这种方法是不是正确的。

 

结论是从control往页面传递值是放进model中，页面根据属性名取值，jsp往control传值是直接映射进方法参数中的

 

 其他代码在附件中，lib包太大，我只把新加的放进lib包单独放上来

其他包去前一篇博文中找吧