博客

• Controller层：表现层（视图）层。用来显示数据和接收用户数据
• Service层：业务逻辑层，用来处理页面。先写接口，后写实现类
• Dao层：持久层（数据访问层）。用来操作数据库

项目中常见的分包

1.controller包

向用户展现的功能，实现用户交互。

public class UserController {

	public UserService userService;
	
	/**
	 * 用户管理列表页
	 */
	@RequestMapping(value="/list",method=RequestMethod.GET)
	public ModelAndView list(ModelAndView model){
		model.setViewName("user/user_list");
		return model;
	}
	
	/**
	 * 获取用户列表
	 */
	@RequestMapping(value="/get_list",method=RequestMethod.POST)
	@ResponseBody
	public Map<String, Object> getList(
			@RequestParam(value="username",required=false,defaultValue="") String username,
			Page page
			){
		Map<String, Object> ret = new HashMap<String, Object>();
		Map<String, Object> queryMap = new HashMap<String, Object>();
		queryMap.put("username", "%"+username+"%");
		queryMap.put("offset", page.getOffset());
		queryMap.put("pageSize", page.getRows());
		ret.put("rows", userService.findList(queryMap));
		ret.put("total", userService.getTotal(queryMap));
		return ret;
	}
	
	/**
	 * 编辑用户操作
	 */
	@RequestMapping(value="/delete",method=RequestMethod.POST)
	@ResponseBody
	public Map<String, String> delete(
			@RequestParam(value="ids[]",required=true) Long[] ids
		){
		Map<String, String> ret = new HashMap<String, String>();
		if(ids == null){
			ret.put("type", "error");
			ret.put("msg", "请选择要删除的数据!");
			return ret;
		}
		String idsString = "";
		for(Long id:ids){
			idsString += id + ",";
		}
		idsString = idsString.substring(0,idsString.length()-1);
		if(userService.delete(idsString) <= 0){
			ret.put("type", "error");
			ret.put("msg", "删除失败!");
			return ret;
		}
		ret.put("type", "success");
		ret.put("msg", "修改成功!");
		return ret;
	}
	
	/**
	 * 编辑用户操作
	 */
	@RequestMapping(value="/edit",method=RequestMethod.POST)
	@ResponseBody
	public Map<String, String> edit(User user){
		Map<String, String> ret = new HashMap<String, String>();
		if(user == null){
			ret.put("type", "error");
			ret.put("msg", "数据出错");
			return ret;
		}
		if(StringUtils.isEmpty(user.getUsername())){
			ret.put("type", "error");
			ret.put("msg", "用户名不能为空!");
			return ret;
		}
		if(StringUtils.isEmpty(user.getPassword())){
			ret.put("type", "error");
			ret.put("msg", "密码不能为空!");
			return ret;
		}
		User existUser = userService.findByUserName(user.getUsername());
		if(existUser != null){
			if(user.getId() != existUser.getId()){
				ret.put("type", "error");
				ret.put("msg", "该用户名已经存在!");
				return ret;
			}
			
		}
		if(userService.edit(user) <= 0){
			ret.put("type", "error");
			ret.put("msg", "修改失败!");
			return ret;
		}
		ret.put("type", "success");
		ret.put("msg", "修改成功!");
		return ret;
	}
	
	
	/**
	 * 添加用户操作
	 */
	@RequestMapping(value="/add",method=RequestMethod.POST)
	@ResponseBody
	public Map<String, String> add(User user){
		Map<String, String> ret = new HashMap<String, String>();
		if(user == null){
			ret.put("type", "error");
			ret.put("msg", "数据出错");
			return ret;
		}
		if(StringUtils.isEmpty(user.getUsername())){
			ret.put("type", "error");
			ret.put("msg", "用户名不能为空!");
			return ret;
		}
		if(StringUtils.isEmpty(user.getPassword())){
			ret.put("type", "error");
			ret.put("msg", "密码不能为空!");
			return ret;
		}
		User existUser = userService.findByUserName(user.getUsername());
		if(existUser != null){
			ret.put("type", "error");
			ret.put("msg", "该用户名已经存在!");
			return ret;
		}
		if(userService.add(user) <= 0){
			ret.put("type", "error");
			ret.put("msg", "添加失败!");
			return ret;
		}
		ret.put("type", "success");
		ret.put("msg", "添加成功!");
		return ret;
	}
	
}

2.service包
用来处理页面。先写接口，后写实现类（用service.impl包）

• 接口
  

public interface UserService {
	public User findByUserName(String username);
	public int add(User user);
	public int edit(User user);
	public int delete(String ids);
	public List<User> findList(Map<String,Object> queryMap);
	public int getTotal(Map<String,Object> queryMap);
}

• 实现类

public class UserServiceImpl implements UserService{

	@Autowired
	private UserDao userDao;
	@Override
	public User findByUserName(String username) {
		// TODO Auto-generated method stub
		return userDao.findByUserName(username);
	}
	@Override
	public int add(User user) {
		// TODO Auto-generated method stub
		return userDao.add(user);
	}
	@Override
	public List<User> findList(Map<String,Object> queryMap) {
		// TODO Auto-generated method stub
		return userDao.findList(queryMap);
	}
	@Override
	public int getTotal(Map<String, Object> queryMap) {
		// TODO Auto-generated method stub
		return userDao.getTotal(queryMap);
	}
	@Override
	public int edit(User user) {
		// TODO Auto-generated method stub
		return userDao.edit(user);
	}
	@Override
	public int delete(String ids) {
		// TODO Auto-generated method stub
		return userDao.delete(ids);
	}

}

3.dao包

操作数据库，实现数据的增删改查

public interface UserDao {
	public User findByUserName(String username);
	public int add(User user);
	public int edit(User user);
	public int delete(String ids);
	public List<User> findList(Map<String,Object> queryMap);
	public int getTotal(Map<String,Object> queryMap);
}

4.entity包

用来编写实体类（模型），entity包中类的数据类型，变量名必须和数据库表的数据类型属性名相对应。

public class User {
	private Long id;//用户id，主键、自增
	private String username;//用户名
	private String password;//密码
	
	public Long getId() {
		return id;
	}
	public void setId(Long id) {
		this.id = id;
	}
	
	
	public String getUsername() {
		return username;
	}
	public void setUsername(String username) {
		this.username = username;
	}
	
	
	public String getPassword() {
		return password;
	}
	public void setPassword(String password) {
		this.password = password;
	}
	
}

5.util包
用来存放工具类。
如字符串的处理，日期类的处理

public class StringUtil {
	
	/**
	 * 将给定的list按照指定的分隔符分割成字符串返回
	 */
	public static String joinString(List<Long> list,String split){
		String ret = "";
		for(Long l:list){
			ret += l + split;
		}
		if(!"".equals(ret)){
			ret = ret.substring(0,ret.length() - split.length());
		}
		return ret;
	}
	
	
	public static String generateSn(String prefix,String suffix){
		return prefix + new Date().getTime() + suffix;
	}
}