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 [email protected] * @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 [email protected] * @description */ @Service @Transactional public class ClassesServiceImpl implements ClassesService { @Resource private ClassesMapper classesMapper; @Override public 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 [email protected] * @description */ @RestController @RequestMapping("/classes") public class ClassesController { @Resource private ClassesService classesService; @GetMapping public 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 [email protected]
* @description
*/
@Table(name = "tb_city")
public class City {
@Id
@Column(name = "c_id")
private String cid; //城市ID
private 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 [email protected]
* @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 [email protected] * @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 [email protected] * @description */ @Service @Transactional public class CityServiceImpl implements CityService { @Resource private CityMapper cityMapper; @Override public 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 [email protected]
* @description
*/
@RestController
@RequestMapping("/city")
public class CityController {
@Resource
private CityService cityService;
@GetMapping
public 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List
provinceList.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
@Override public 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 [email protected] * @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 [email protected] * @description */ @Service @Transactional public class CourseServiceImpl implements CourseService { @Resource private CourseMapper courseMapper; @Override public 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 [email protected]
* @description
*/
@RestController
@RequestMapping("/course")
public class CourseController {
@Resource
private CourseService courseService;
/**
* 查询所有课程
* @return
*/
@GetMapping
public 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
@Override public List<Course> selectAllBySid(Integer sid) { List<Course> courseList = courseMapper.selectAllBySid(sid); return courseList; }