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学生管理

近年来，Java作为一门广泛应用于后端开发的编程语言，具备了广泛的应用领域和丰富的开发资源。在前几天的博客中，我们探讨了如何搭建前后端环境，为接下来的开发工作打下了坚实的基础。今天，我们将进一步扩展我们的项目，并实现一个令人期待的功能——查询所有学生的信息。

这个功能对于学生管理系统来说至关重要。我们可以通过这个功能一次性查看系统中所有学生的信息，包括他们的姓名、年龄、以及其他重要的个人数据。无论是学生导员、教工还是学生自己，都可以方便地获取到所需的信息。让我们继续深入学习并实现这个功能吧！

2.1 查询所有：后端

2.1.2 分析

• 查询所有学生
  • 条件查询：班级、姓名（模糊）、年龄（范围）
  • 分页查询
  • 基本信息：编号、姓名、年龄、生日、性别
  • 关联信息：班级、选课数、选课详情

2.1.2 domain

1）学生

package com.czxy.domain;import lombok.Data;import javax.persistence.Column;
import javax.persistence.Id;
import javax.persistence.Table;
import javax.persistence.Transient;
import java.util.Date;
import java.util.List;/*** @author 薛慕昭* @description*/
@Table(name="tb_student")
public class Student {@Id@Column(name="s_id")private Integer sid;            //学生IDprivate String sname;           //姓名private Integer age;            //年龄private Date birthday;          //生日private String gender;          //性别@Column(name="c_id")private Integer cid;            //所属班级id//多对一：多个学生属于一个班级@Transient                     //临时，表示数据库没有对应列private Classes classes;        //所属班级private String cityIds;         //城市：320000,321300,321322//多对多：不同学生选修不同的课程@Transient                     //临时，表示数据库没有对应列private List<Course> courseList;@Transient                      //临时，表示数据库没有对应列private Integer courseCount;     //选课数

2）班级

package com.czxy.domain;import javax.persistence.Column;
import javax.persistence.Id;
import javax.persistence.Table;/*** @author 薛慕昭* @description*/
@Table(name = "tb_class")
public class Classes {@Idprivate Integer cid;private String cname;           //班级名称@Column(name = "teacher1_id")private int teacher1Id;         //授课老师@Column(name = "teacher2_id")private int teacher2Id;         //助理老师@Column(name = "teacher3_id")private int teacher3Id;         //辅导员老师

3）选课

package com.czxy.domain;import javax.persistence.Column;
import javax.persistence.Id;
import javax.persistence.Table;/*** @author 薛慕昭* @description*/
@Table(name = "tb_course")
public class Course {@Id@Column(name = "c_id")private Integer cid;private String cname;@Column(name = "`desc`")private String desc;

2.1.3 Vo

package com.czxy.vo;/*** @author 薛慕昭* @description*/
public class StudentVo {private Integer classId;        //班级idprivate String studentName;     //学生姓名private Integer startAge;       //开始年龄private Integer endAge;         //结束年龄

2.1.4 dao

1）学生

package com.czxy.mapper;import com.czxy.domain.Student;
import tk.mybatis.mapper.common.Mapper;/*** @author 薛慕昭* @description*/
public interface StudentMapper extends Mapper<Student> {
}

2）班级

package com.czxy.mapper;import com.czxy.domain.Classes;
import tk.mybatis.mapper.common.Mapper;/*** @author 薛慕昭* @description*/
public interface ClassesMapper extends Mapper<Classes> {
}

3）选课

package com.czxy.mapper;import com.czxy.domain.Course;
import org.apache.ibatis.annotations.Param;
import org.apache.ibatis.annotations.Select;
import tk.mybatis.mapper.common.Mapper;import java.util.List;/*** @author 薛慕昭* @description*/
public interface CourseMapper extends Mapper<Course> {/*** 查询指定学生的所有课程* @param sid* @return*/@Select("select c.* from tb_course c, tb_student_course sc where c.c_id = sc.c_id and sc.s_id = #{sid}")public List<Course> selectAllBySid(@Param("sid") Integer sid);
}

2.1.5 service

• 接口

  package com.czxy.service;import com.czxy.domain.Student;
  import com.czxy.vo.StudentVo;
  import com.github.pagehelper.PageInfo;/*** @author 薛慕昭* @description*/
  public interface StudentService {/*** 查询（基本、分页、条件）* @param studentVo* @param pageNum* @param pageSize* @return*/PageInfo<Student> condition(StudentVo studentVo, Integer pageNum, Integer pageSize);
  }

• 实现类

  package com.czxy.service.impl;import com.czxy.domain.Classes;
  import com.czxy.domain.Course;
  import com.czxy.domain.Student;
  import com.czxy.mapper.ClassesMapper;
  import com.czxy.mapper.CourseMapper;
  import com.czxy.mapper.StudentMapper;
  import com.czxy.service.StudentService;
  import com.czxy.vo.StudentVo;
  import com.github.pagehelper.PageHelper;
  import com.github.pagehelper.PageInfo;
  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 薛慕昭* @description*/
  @Service
  @Transactional
  public class StudentServiceImpl implements StudentService {@Resourceprivate StudentMapper studentMapper;@Resourceprivate ClassesMapper classesMapper;@Resourceprivate CourseMapper courseMapper;@Overridepublic PageInfo<Student> condition(StudentVo studentVo, Integer pageNum, Integer pageSize) {//1 拼凑条件// 1.0 获得条件对象Example studentExample = new Example(Student.class);Example.Criteria studentCriteria = studentExample.createCriteria();// 1.1 班级if(studentVo.getClassId() != null) {studentCriteria.andEqualTo("cid", studentVo.getClassId());}// 1.2 姓名 不能为null，不能为“” ,  %张%if(studentVo.getStudentName() != null && !"".equals(studentVo.getStudentName())) {studentCriteria.andLike("sname", "%"+studentVo.getStudentName()+"%");}// 1.3 年龄   30~50if(studentVo.getStartAge() != null) {studentCriteria.andGreaterThanOrEqualTo("age", studentVo.getStartAge());}if(studentVo.getEndAge() != null) {studentCriteria.andLessThanOrEqualTo("age", studentVo.getEndAge());}//2 分页PageHelper.startPage(pageNum, pageSize);//3.查询List<Student> studentList = studentMapper.selectByExample(studentExample);//4 关联for(Student student : studentList) {// 4.1 班级信息Classes classes = classesMapper.selectByPrimaryKey(student.getCid());student.setClasses(classes);// 查询学生选修的可成List<Course> courseList = courseMapper.selectAllBySid(student.getSid());// 4.2 选课数student.setCourseCount(courseList.size());// 4.3 选课详情student.setCourseList(courseList);}//5 封装PageInfo<Student> pageInfo = new PageInfo<>(studentList);return pageInfo;}
  }

2.1.6 controller

package com.czxy.controller;import com.czxy.domain.Student;
import com.czxy.service.StudentService;
import com.czxy.vo.StudentVo;
import com.github.pagehelper.PageInfo;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;import javax.annotation.Resource;/*** @author 薛慕昭* @description*/
@RestController
@RequestMapping("/student")
public class StudentController {@Resourceprivate StudentService studentService;@PostMapping("/condition/{pageSize}/{pageNum}")public ResponseEntity<PageInfo<Student>> condition(@RequestBody StudentVo studentVo,@PathVariable("pageSize") Integer pageSize,@PathVariable("pageNum") Integer pageNum) {//查询PageInfo<Student> pageInfo = studentService.condition(studentVo, pageNum, pageSize );//处理结果return ResponseEntity.ok(pageInfo);}}

2.1.7 测试

2.2 查询所有：前端

2.2.1 需求

2.2.2 列表展示

<template><div><!-- 列表start --><el-table:data="pageInfo.list"stripestyle="width: 100%"><el-table-columnprop="sid"fixedlabel="学生ID"width="180"></el-table-column><el-table-columnprop="classes.cname"fixedlabel="班级名称"width="180"></el-table-column><el-table-columnprop="sname"label="学生姓名"width="180"></el-table-column><el-table-columnprop="age"label="年龄"width="180"></el-table-column><el-table-columnprop="birthday"label="生日"width="180"></el-table-column><el-table-columnprop="gender"label="性别"width="180"><template slot-scope="scope">{{scope.row.gender == 1 ? '男': '女'}}</template></el-table-column><el-table-columnprop="courseCount"label="选课数"width="180"></el-table-column><el-table-columnlabel="选课详情"width="300"><template slot-scope="scope"><el-tag v-for="(course,index) in scope.row.courseList" :key="index">{{course.cname}}</el-tag></template></el-table-column><el-table-columnwidth="180"fixed="right"label="操作"><template slot-scope="scope"><el-button size="mini">编辑</el-button><el-button size="mini" type="danger">删除</el-button></template></el-table-column></el-table><!-- 列表end -->{{pageInfo}}</div>
</template><script>
export default {data() {return {studentVo: {      //查询条件classId: '',studentName: '',startAge: '',endAge: ''},pageInfo: {     //分页条件pageNum: 1,pageSize: 2}}},methods: {async selectAllStudent() {//处理请求路径let url = `/student/condition/${this.pageInfo.pageSize}/${this.pageInfo.pageNum}`//发送ajaxlet {data} = await this.$http.post(url, this.studentVo)//保存结果this.pageInfo = data}},mounted() {   //页面加载成功this.selectAllStudent()},
}
</script><style></style>

2.2.3 条件表单

• 页面加载成功后，查询所有的班级

• 编写表单：展示班级列表、绑定条件参数、绑定查询按钮

<template><div><!-- 查询表单start --><el-form :inline="true" :model="studentVo" size="mini" class="demo-form-inline"><el-form-item label="班级"><el-select v-model="studentVo.classId" clearable @change="selectAllStudent" placeholder="请选择班级"><el-option v-for="(classes,index) in classesList" :key="index" :label="classes.cname" :value="classes.cid"></el-option></el-select></el-form-item><el-form-item label="姓名"><el-input v-model="studentVo.studentName" @keyup.enter.native="selectAllStudent" clearable placeholder="请输入姓名"></el-input></el-form-item><el-form-item label="年龄"><el-col :span="11"><el-input v-model="studentVo.startAge" clearable placeholder="请输入开始年龄"></el-input></el-col><el-col class="line" :span="2">-</el-col><el-col :span="11"><el-input v-model="studentVo.endAge" clearable placeholder="请输入结束年龄"></el-input></el-col></el-form-item><el-form-item><el-button type="primary" @click="selectAllStudent">查询</el-button></el-form-item></el-form><!-- 查询表单end --><!-- 列表start --><el-table:data="pageInfo.list"stripestyle="width: 100%"><el-table-columnprop="sid"fixedlabel="学生ID"width="180"></el-table-column><el-table-columnprop="classes.cname"fixedlabel="班级名称"width="180"></el-table-column><el-table-columnprop="sname"label="学生姓名"width="180"></el-table-column><el-table-columnprop="age"label="年龄"width="180"></el-table-column><el-table-columnprop="birthday"label="生日"width="180"></el-table-column><el-table-columnprop="gender"label="性别"width="180"><template slot-scope="scope">{{scope.row.gender == 1 ? '男': '女'}}</template></el-table-column><el-table-columnprop="courseCount"label="选课数"width="180"></el-table-column><el-table-columnlabel="选课详情"width="300"><template slot-scope="scope"><el-tag v-for="(course,index) in scope.row.courseList" :key="index">{{course.cname}}</el-tag></template></el-table-column><el-table-columnwidth="180"fixed="right"label="操作"><template slot-scope="scope"><el-button size="mini">编辑</el-button><el-button size="mini" type="danger">删除</el-button></template></el-table-column></el-table><!-- 列表end -->{{pageInfo}}</div>
</template><script>
export default {data() {return {studentVo: {      //查询条件classId: '',studentName: '',startAge: '',endAge: ''},pageInfo: {     //分页条件pageNum: 1,pageSize: 5},classesList: [],    //所有班级}},methods: {async selectAllStudent() {//处理请求路径let url = `/student/condition/${this.pageInfo.pageSize}/${this.pageInfo.pageNum}`//发送ajaxlet {data} = await this.$http.post(url, this.studentVo)//保存结果this.pageInfo = data},async selectAllClasses() {let { data } = await this.$http.get('/classes')this.classesList = data}},mounted() {   //页面加载成功//查询所有学生this.selectAllStudent()//查询所有班级this.selectAllClasses()},
}
</script><style>.line {text-align: center;}
</style>

2.2.4 分页条

• 显示分页条

  

• 编写分页需要触发函数

  

<template><div><!-- 查询表单start --><el-form :inline="true" :model="studentVo" size="mini" class="demo-form-inline"><el-form-item label="班级"><el-select v-model="studentVo.classId" clearable @change="selectAllStudent" placeholder="请选择班级"><el-option v-for="(classes,index) in classesList" :key="index" :label="classes.cname" :value="classes.cid"></el-option></el-select></el-form-item><el-form-item label="姓名"><el-input v-model="studentVo.studentName" @keyup.enter.native="selectAllStudent" clearable placeholder="请输入姓名"></el-input></el-form-item><el-form-item label="年龄"><el-col :span="11"><el-input v-model="studentVo.startAge" clearable placeholder="请输入开始年龄"></el-input></el-col><el-col class="line" :span="2">-</el-col><el-col :span="11"><el-input v-model="studentVo.endAge" clearable placeholder="请输入结束年龄"></el-input></el-col></el-form-item><el-form-item><el-button type="primary" @click="selectAllStudent">查询</el-button></el-form-item></el-form><!-- 查询表单end --><!-- 列表start --><el-table:data="pageInfo.list"stripestyle="width: 100%"><el-table-columnprop="sid"fixedlabel="学生ID"width="180"></el-table-column><el-table-columnprop="classes.cname"fixedlabel="班级名称"width="180"></el-table-column><el-table-columnprop="sname"label="学生姓名"width="180"></el-table-column><el-table-columnprop="age"label="年龄"width="180"></el-table-column><el-table-columnprop="birthday"label="生日"width="180"></el-table-column><el-table-columnprop="gender"label="性别"width="180"><template slot-scope="scope">{{scope.row.gender == 1 ? '男': '女'}}</template></el-table-column><el-table-columnprop="courseCount"label="选课数"width="180"></el-table-column><el-table-columnlabel="选课详情"width="300"><template slot-scope="scope"><el-tag v-for="(course,index) in scope.row.courseList" :key="index">{{course.cname}}</el-tag></template></el-table-column><el-table-columnwidth="180"fixed="right"label="操作"><template slot-scope="scope"><el-button size="mini">编辑</el-button><el-button size="mini" type="danger">删除</el-button></template></el-table-column></el-table><!-- 列表end --><!-- 分页条start --><el-pagination@size-change="handleSizeChange"@current-change="handleCurrentChange":current-page="pageInfo.pageNum":page-sizes="[1,2,3,5,10]":page-size="pageInfo.pageSize"layout="total, sizes, prev, pager, next, jumper":total="pageInfo.total"></el-pagination><!-- 分页条end --></div>
</template><script>
export default {data() {return {studentVo: {      //查询条件classId: '',studentName: '',startAge: '',endAge: ''},pageInfo: {     //分页条件pageNum: 1,     //当前页（第几页）pageSize: 2     //每页个数},classesList: [],    //所有班级}},methods: {async selectAllStudent() {//处理请求路径let url = `/student/condition/${this.pageInfo.pageSize}/${this.pageInfo.pageNum}`//发送ajaxlet {data} = await this.$http.post(url, this.studentVo)//保存结果this.pageInfo = data},async selectAllClasses() {let { data } = await this.$http.get('/classes')this.classesList = data},handleSizeChange(val) {//修改 每页个数//console.log(`每页 ${val} 条`);this.pageInfo.pageSize = valthis.pageInfo.pageNum = 1//再查询this.selectAllStudent()},handleCurrentChange(val) {//修改当前页//console.log(`当前页: ${val}`);this.pageInfo.pageNum = val//再查询this.selectAllStudent()}},mounted() {   //页面加载成功//查询所有学生this.selectAllStudent()//查询所有班级this.selectAllClasses()},
}
</script><style>.line {text-align: center;}
</style>

通过本文的学习，我们成功地实现了学生管理项目的查询所有功能。我们通过构建一个学生管理系统，并添加了测试数据，以模拟真实的学生信息。通过调用系统提供的showAllStudents()方法，我们可以轻松地查看并打印所有学生的信息。这个功能为学生管理系统增添了强大的查询能力，使得管理工作更加高效和便捷。

在今天的学习中，我们不仅巩固了Java的基础知识，还深入了解了如何处理和展示大量的数据。随着项目的发展，我们将继续探索更多有趣和实用的功能，并逐步建立一个完整的学生管理系统。希望本文对你有所启发和帮助，如果你有任何疑问或建议，请随时与我们分享。期待下一篇博客，继续探索Java开发的奇妙世界！

SizeChange(val) {//修改 每页个数//console.log(`每页 ${val} 条`);this.pageInfo.pageSize = valthis.pageInfo.pageNum = 1//再查询this.selectAllStudent()},handleCurrentChange(val) {//修改当前页//console.log(`当前页: ${val}`);this.pageInfo.pageNum = val//再查询this.selectAllStudent()}},mounted() {   //页面加载成功//查询所有学生this.selectAllStudent()//查询所有班级this.selectAllClasses()},
}
</script><style>.line {text-align: center;}
</style>

通过本文的学习，我们成功地实现了学生管理项目的查询所有功能。我们通过构建一个学生管理系统，并添加了测试数据，以模拟真实的学生信息。通过调用系统提供的showAllStudents()方法，我们可以轻松地查看并打印所有学生的信息。这个功能为学生管理系统增添了强大的查询能力，使得管理工作更加高效和便捷。

在今天的学习中，我们不仅巩固了Java的基础知识，还深入了解了如何处理和展示大量的数据。随着项目的发展，我们将继续探索更多有趣和实用的功能，并逐步建立一个完整的学生管理系统。希望本文对你有所启发和帮助，如果你有任何疑问或建议，请随时与我们分享。期待下一篇博客，继续探索Java开发的奇妙世界！