Java项目学生管理系统六后端补充

班级管理

1 班级列表：后端

• 编写JavaBean【已有】
• 编写Mapper【已有】
• 编写Service
• 编写controller

• 编写Service

  • 接口

    package com.czxy.service;import com.czxy.domain.Classes;import java.util.List;/*** @author 桐叔* @email liangtong@itcast.cn* @description*/
    public interface ClassesService {/*** 查询所有* @return*/public List<Classes> selectAll();
    }

  • 实现类

    package com.czxy.service.impl;import com.czxy.domain.Classes;
    import com.czxy.mapper.ClassesMapper;
    import com.czxy.service.ClassesService;
    import org.springframework.stereotype.Service;
    import org.springframework.transaction.annotation.Transactional;import javax.annotation.Resource;
    import java.util.List;/*** @author 桐叔* @email liangtong@itcast.cn* @description*/
    @Service
    @Transactional
    public class ClassesServiceImpl implements ClassesService {@Resourceprivate ClassesMapper classesMapper;@Overridepublic List<Classes> selectAll() {List<Classes> classesList = classesMapper.selectAll();return classesList;}
    }

• 编写controller

  package com.czxy.controller;import com.czxy.domain.Classes;
  import com.czxy.service.ClassesService;
  import org.springframework.http.ResponseEntity;
  import org.springframework.web.bind.annotation.GetMapping;
  import org.springframework.web.bind.annotation.RequestMapping;
  import org.springframework.web.bind.annotation.RestController;import javax.annotation.Resource;
  import java.util.List;/*** @author 桐叔* @email liangtong@itcast.cn* @description*/
  @RestController
  @RequestMapping("/classes")
  public class ClassesController {@Resourceprivate ClassesService classesService;@GetMappingpublic ResponseEntity<List<Classes>> selectAll() {// 查询List<Classes> classesList = classesService.selectAll();// 返回return ResponseEntity.ok(classesList);}
  }

城市管理

1 查询所有城市：后端

1 JavaBean

package com.czxy.domain;import javax.persistence.Column;
import javax.persistence.Id;
import javax.persistence.Table;
import java.util.ArrayList;
import java.util.List;/*** @author 桐叔* @email liangtong@itcast.cn* @description*/
@Table(name = "tb_city")
public class City {@Id@Column(name = "c_id")private String cid;                 //城市IDprivate String cityName;            //城市名称private String parentId;            //父ID//一对多：一个城市(省/市)拥有多个子城市(多个市/多个县) ，new对象为了操作【方便】private List<City> children = new ArrayList<>();//....
}/*
CREATE TABLE tb_city(c_id VARCHAR(32) PRIMARY KEY COMMENT '城市ID',city_name VARCHAR(20) COMMENT '城市名称' ,parent_id VARCHAR(32) COMMENT '父ID'
);*/

2 Mapper

package com.czxy.mapper;import com.czxy.domain.City;
import tk.mybatis.mapper.common.Mapper;/*** @author 桐叔* @email liangtong@itcast.cn* @description*/
public interface CityMapper extends Mapper<City> {
}

3 Service

• 接口

  package com.czxy.service;import com.czxy.domain.City;import java.util.List;/*** @author 桐叔* @email liangtong@itcast.cn* @description*/
  public interface CityService {/*** 查询所有（省、市、县）* @return*/public List<City> selectAll();
  }

• 实现类

  package com.czxy.service.impl;import com.czxy.domain.City;
  import com.czxy.mapper.CityMapper;
  import com.czxy.service.CityService;
  import org.springframework.stereotype.Service;
  import org.springframework.transaction.annotation.Transactional;
  import tk.mybatis.mapper.entity.Example;import javax.annotation.Resource;
  import java.util.List;/*** @author 桐叔* @email liangtong@itcast.cn* @description*/
  @Service
  @Transactional
  public class CityServiceImpl implements CityService {@Resourceprivate CityMapper cityMapper;@Overridepublic List<City> selectAll() {//1 条件查询：排序Example example = new Example(City.class);example.orderBy("parentId").asc();      //升序//2 查询List<City> cityList = cityMapper.selectByExample(example);return cityList;}
  }

4 Controller

package com.czxy.controller;import com.czxy.domain.City;
import com.czxy.service.CityService;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;import javax.annotation.Resource;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;/*** @author 桐叔* @email liangtong@itcast.cn* @description*/
@RestController
@RequestMapping("/city")
public class CityController {@Resourceprivate CityService cityService;@GetMappingpublic ResponseEntity<List<City>> selectAll() {// 1 查询所有 省/市/县List<City> cityList = cityService.selectAll();// 2 处理数据 省(市(县))// 2.1.1 提供Map，用于缓存所有城市，目的：方便子城市找到父城市// map.id 城市id，方便子获得， map.value 城市Map<String, City> cacheMap = new HashMap<>();// 2.1.2 提供List，存放所有的省List<City> provinceList = new ArrayList<>();// 2.2 遍历所有城市for(City city: cityList) {// 2.3.1 从map获得父城市City parentCity = cacheMap.get(city.getParentId());if(parentCity == null) {// 2.3.2 1)如果没有获得父城市，表示就是省，直接添加ListprovinceList.add(city);} else {// 2.3.2 2)如果获得父城市，表示市、县，将器追加到父城市的子列表中parentCity.getChildren().add(city);}// 2.3.3 当前城市添加到map中，方便下一次自己的子城市可以获得自己cacheMap.put(city.getCid(), city);}//3 返回所有的省return ResponseEntity.ok(provinceList);}
}

查询指定父id的所有城市：后端

1 Service

• 接口

  

      /*** 通过父id查询所有* @param parentId* @return*/public List<City> selectByParentId(String parentId);
  

• 实现类

  

      @Overridepublic List<City> selectByParentId(String parentId) {//1 条件Example example = new Example(City.class);Example.Criteria criteria = example.createCriteria();criteria.andEqualTo("parentId", parentId);//2 查询List<City> cityList = cityMapper.selectByExample(example);//3 返回return cityList;}
  

2 Controller

    /*** 通过父id查询* @param pid* @return*/@GetMapping("/parent/{pid}")public ResponseEntity<List<City>> selectAllByParentId(@PathVariable("pid") String pid) {//查询List<City> cityList = cityService.selectByParentId(pid);//返回return ResponseEntity.ok(cityList);}

课程管理

1查询所有：后端

1 Service

• 接口

  package com.czxy.service;import com.czxy.domain.Course;import java.util.List;/*** @author 桐叔* @email liangtong@itcast.cn* @description*/
  public interface CourseService {/*** 查询所有课程* @return*/public List<Course> selectAll();
  }

• 实现类

  package com.czxy.service.impl;import com.czxy.domain.Course;
  import com.czxy.mapper.CourseMapper;
  import com.czxy.service.CourseService;
  import org.springframework.stereotype.Service;
  import org.springframework.transaction.annotation.Transactional;import javax.annotation.Resource;
  import java.util.List;/*** @author 桐叔* @email liangtong@itcast.cn* @description*/
  @Service
  @Transactional
  public class CourseServiceImpl implements CourseService {@Resourceprivate CourseMapper courseMapper;@Overridepublic List<Course> selectAll() {List<Course> courseList = courseMapper.selectAll();return courseList;}
  }

2 Controller

package com.czxy.controller;import com.czxy.domain.Course;
import com.czxy.service.CourseService;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;import javax.annotation.Resource;
import java.util.List;/*** @author 桐叔* @email liangtong@itcast.cn* @description*/
@RestController
@RequestMapping("/course")
public class CourseController {@Resourceprivate CourseService courseService;/*** 查询所有课程* @return*/@GetMappingpublic ResponseEntity<List<Course>> selectAll() {//查询List<Course> courseList = courseService.selectAll();//返回return ResponseEntity.ok(courseList);}
}

2 查询指定学生的所有课程：后端

1 Mapper【已有】

2 Service

• 接口

  

      /*** 查询指定学生的所有课程* @param sid* @return*/public List<Course> selectAllBySid(Integer sid);
  

• 实现类

  

      @Overridepublic List<Course> selectAllBySid(Integer sid) {List<Course> courseList = courseMapper.selectAllBySid(sid);return courseList;}