前言
在day1中，我们已经完成了基本的框架搭建，接下来继续完成controller层和前端页面
源代码项目结构图
开发步骤
DAO->Service->Controller
Result
@JsonInclude(value = JsonInclude.Include.NON_NULL)
public class Result {private int code;private String message;private List<Object> data;public Result() {}public Result(int code, String message) {this.code = code;this.message = message;}public Result(int code, String message, List<Object> data) {this.code = code;this.message = message;this.data = data;}public int getCode() {return code;}public void setCode(int code) {this.code = code;}public String getMessage() {return message;}public void setMessage(String message) {this.message = message;}public List<Object> getData() {return data;}public void setData(List<Object> data) {this.data = data;}
}
定义Result类，统一返回结果，@JsonInclude(value = JsonInclude.Include.NON_NULL)
注解的作用是，当Result类中某个属性没有值时，会忽略该属性，不进行数据传递
UserDao
开发一个项目的步骤应该是从底向上的一个过程，先写dao，在写service，最后写controller和对应的前端页面
public interface UserDao {//模糊查询List<User> getLikeUsers(Map<String,Object> user);//模糊查询个数Integer getLikeUsersCount(Map<String,Object> user);//新增用户Integer insertUser(User user);// 修改用户int updateUser(User user);//删除用户int delUser(User user);//根据id查询指定用户User selectUserById(User user);
}
项目所需的sql支持如上：包括模糊查询和CRUD
注意：这里的根据id查询指定用户，我传递的参数类型为对象，实际上只需要user的id即可，我这么写的目的，是为了简化开发
UserDao.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapperPUBLIC "-//mybatis.org//DTD Mapper 3.0//EN""http://mybatis.org/dtd/mybatis-3-mapper.dtd" ><mapper namespace="com.csx.dao.UserDao"><insert id="insertUser" parameterType="User">insert into t_user(name,age)values (#{name},#{age})</insert><update id="updateUser">update t_user set name = #{name},age = #{age}where id = #{id}</update><delete id="delUser">delete from t_user where id = #{id}</delete><!-- select * from t_user where name like concat('%',#{user.name},'%') order by id desc--><select id="getLikeUsers" parameterType="map" resultType="User">select* from t_user<where>name like concat('%',#{user.name},'%')<if test="user.age!=null">and age=#{user.age}</if></where>order by id desc</select><select id="getLikeUsersCount" parameterType="map" resultType="int">select count(1) from t_user where name like concat('%',#{user.name},'%')</select><select id="selectUserById" resultType="com.csx.entity.User" parameterType="User">select * from t_user where id=#{id}</select>
</mapper>UserService
package com.csx.service;import com.csx.entity.User;
import com.github.pagehelper.Page;import java.util.Map;public interface UserService {//分页查询Page queryLikeUsers(Map<String,Object> cond);//新增用户int addUser(User user);//修改用户int changeUser(User user);//删除用户int removeUser(User user);User getUser(User user);
}
书写业务支持
UserServiceImpl
package com.csx.service.impl;import com.csx.dao.UserDao;
import com.csx.entity.User;
import com.csx.service.UserService;
import com.github.pagehelper.Page;
import com.github.pagehelper.PageHelper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;import java.util.List;
import java.util.Map;
@Service(value = "userService")
public class UserServiceImpl implements UserService {@Autowiredprivate UserDao userDao;@Overridepublic Page queryLikeUsers(Map<String, Object> cond) {Page page =new Page();
// //查询记录总数
// page.setTotal(userDao.getLikeUsersCount(cond));
// //每页大小（每页记录数）int pageSize =Integer.parseInt(String.valueOf(cond.get("pageSize")));
// page.setPageSize(pageSize);
// //当前页int currentPageNum =Integer.parseInt(String.valueOf(cond.get("pageNum")));
// page.setPageNum(currentPageNum);//开启分页page= PageHelper.startPage(currentPageNum,pageSize);
// List<User> list = userDao.getLikeUsers(cond);userDao.getLikeUsers(cond);return page;}@Overridepublic int addUser(User user) {return userDao.insertUser(user);}@Overridepublic int changeUser(User user) {return userDao.updateUser(user);}@Overridepublic int removeUser(User user) {return userDao.delUser(user);}@Overridepublic User getUser(User user) {return userDao.selectUserById(user);}
}
关键点在于如何使用PageHelper分页插件完成分页功能，分页功能主要关注两个数据，一个是当前页码，另一个查询总条数（总记录数）
UserController
@RestController
@RequestMapping("/user")
public class UserController {@Autowiredprivate UserService userService;@RequestMapping("/toList")public ModelAndView toList(){return new ModelAndView("list");}//分页查询@RequestMapping("/getPage")public Map queryUserByPage(int pageNum, int pageSize, User user) {Map map = new HashMap();map.put("pageSize", pageSize);map.put("pageNum", pageNum);map.put("user", user);//调用ServicePage page = userService.queryLikeUsers(map);map.put("page", page);map.put("totalPage", page.getPages());return map;}@RequestMapping("/add")public Result addUser(User u){userService.addUser(u);return new Result(200,"success");}@RequestMapping("/editPage")public ModelAndView getUser(User user) {User u = userService.getUser(user);System.out.println(u);Map map = new HashMap();map.put("data", u);return new ModelAndView("edit", map);}@RequestMapping("/updateUser")public Result updateUser(User u) {userService.changeUser(u);return new Result();}@RequestMapping("/delUser")public Result delUser(User user) {userService.removeUser(user);return new Result();}}
因为我们使用freemarker技术，又因为我们不能直接访问ftl后缀的文件，所以需要先访问controller层，在根据ModelAndView进行页面跳转（list），然后页面通过ajax技术，异步获取后台数据。
总结
后台的工作准备完毕，现在需要完成前端页面，转到day3