Java项目学生管理系统二查询所有

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

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2.1.2 domain

在这里插入图片描述

1）学生

在这里插入图片描述

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ID

    private 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 {
    @Id
    private 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

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package com.czxy.vo;

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

2.1.4 dao

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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 {

    @Resource
    private StudentMapper studentMapper;
    @Resource
    private ClassesMapper classesMapper;
    @Resource
    private CourseMapper courseMapper;

    @Override
    public 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   30~50
        if(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 {

    @Resource
    private 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

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2.2 查询所有：前端

2.2.1 需求

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2.2.2 列表展示

<template>
  <div>
    <!-- 列表start -->
    <el-table
      :data="pageInfo.list"
      stripe
      style="width: 100%">
      <el-table-column
        prop="sid"
        fixed
        label="学生ID"
        width="180">
      </el-table-column>
      <el-table-column
        prop="classes.cname"
        fixed
        label="班级名称"
        width="180">
      </el-table-column>
      <el-table-column
        prop="sname"
        label="学生姓名"
        width="180">
      </el-table-column>
      <el-table-column
        prop="age"
        label="年龄"
        width="180">
      </el-table-column>
      <el-table-column
        prop="birthday"
        label="生日"
        width="180">
      </el-table-column>
      <el-table-column
        prop="gender"
        label="性别"
        width="180">
        <template slot-scope="scope">
          {{scope.row.gender == 1 ? '男': '女'}}
        </template>
      </el-table-column>
      <el-table-column
        prop="courseCount"
        label="选课数"
        width="180">
      </el-table-column>
      <el-table-column
        label="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-column
        width="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ajax
      let {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

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编写表单：展示班级列表、绑定条件参数、绑定查询按钮

在这里插入图片描述

<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"
      stripe
      style="width: 100%">
      <el-table-column
        prop="sid"
        fixed
        label="学生ID"
        width="180">
      </el-table-column>
      <el-table-column
        prop="classes.cname"
        fixed
        label="班级名称"
        width="180">
      </el-table-column>
      <el-table-column
        prop="sname"
        label="学生姓名"
        width="180">
      </el-table-column>
      <el-table-column
        prop="age"
        label="年龄"
        width="180">
      </el-table-column>
      <el-table-column
        prop="birthday"
        label="生日"
        width="180">
      </el-table-column>
      <el-table-column
        prop="gender"
        label="性别"
        width="180">
        <template slot-scope="scope">
          {{scope.row.gender == 1 ? '男': '女'}}
        </template>
      </el-table-column>
      <el-table-column
        prop="courseCount"
        label="选课数"
        width="180">
      </el-table-column>
      <el-table-column
        label="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-column
        width="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ajax
      let {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"
      stripe
      style="width: 100%">
      <el-table-column
        prop="sid"
        fixed
        label="学生ID"
        width="180">
      </el-table-column>
      <el-table-column
        prop="classes.cname"
        fixed
        label="班级名称"
        width="180">
      </el-table-column>
      <el-table-column
        prop="sname"
        label="学生姓名"
        width="180">
      </el-table-column>
      <el-table-column
        prop="age"
        label="年龄"
        width="180">
      </el-table-column>
      <el-table-column
        prop="birthday"
        label="生日"
        width="180">
      </el-table-column>
      <el-table-column
        prop="gender"
        label="性别"
        width="180">
        <template slot-scope="scope">
          {{scope.row.gender == 1 ? '男': '女'}}
        </template>
      </el-table-column>
      <el-table-column
        prop="courseCount"
        label="选课数"
        width="180">
      </el-table-column>
      <el-table-column
        label="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-column
        width="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ajax
      let {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 = val
      this.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 = val
      this.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>