前端代码部分：

右上方小铃铛组件

 

 

<template>
  <div>

    <el-popover placement="bottom" :width="280" trigger="click">
      <template #reference>
        <el-badge :is-dot="isDot" class="item" style="line-height: 40px">
          <!--      <svg-icon :icon-class="Bell" @click="toggle" />-->
          <el-icon  class="el-icon-bell" style="font-size: 20px;cursor:pointer;transform: translateY(0.6px);" @click="bellClick"></el-icon>
<!--          <svg-icon class-name="search-icon" icon-class="search" @click.stop="click" />-->
        </el-badge>
      </template>
      <div v-if="noticeList.length>0">
        <el-tabs>
          <el-tab-pane label="通知">
            <div v-for="(item,index) in noticeList.slice(0,5)">
              <table>
                <tr>
                  <td rowspan="2">
                    <el-avatar icon="message" style="width:20px;height:20px;margin-right: 20px;background-color: #4d88ff"/>
                  </td>
                  <td>
                    <el-tooltip
                      class="box-item"
                      effect="dark"
                      :content="item.messageTitle"
                      placement="bottom"
                    >
                      <el-link  type="primary" @click="handleRead(item)" style="font-size: 15px">
                        {{item.messageTitle}}
                      </el-link>
                    </el-tooltip>
                  </td>
                </tr>
                <tr>
                  <td>
                    <span>{{item.createTime}}</span>
                  </td>
                </tr>
              </table>
              <hr v-if="index<noticeList.length-1" color="#e6e6e6"/>
            </div>
            <div style="text-align: center;margin-top: 10px">
              <el-button v-show="showAllBtn" align="center" type="primary" @click="showAll()">查看更多</el-button>
            </div>
          </el-tab-pane>
        </el-tabs>


      </div>
      <div v-else>
        <div style="text-align: center">暂无未读消息</div>
      </div>
    </el-popover>
    <!-- 添加或修改我的消息对话框 -->
    <el-dialog title="我的消息" :visible.sync="open" width="500px" append-to-body>
      <el-form ref="form" :model="form" :rules="rules" label-width="80px">
        <el-form-item label="消息标题" prop="messageTitle">
          <el-input disabled v-model="form.messageTitle" placeholder="请输入消息标题" />
        </el-form-item>
        <!--        <el-form-item label="用户ID" prop="userId">-->
        <!--          <el-input disabled v-model="form.userId" placeholder="请输入用户ID" />-->
        <!--        </el-form-item>-->
        <el-form-item label="消息内容">
          <editor :readOnly="true" v-model="form.messageContent" :min-height="192"/>
        </el-form-item>
        <!--        <el-form-item label="备注" prop="remark">-->
        <!--          <el-input disabled v-model="form.remark" placeholder="请输入备注" />-->
        <!--        </el-form-item>-->
      </el-form>
      <div slot="footer" class="dialog-footer">
        <!--        <el-button type="primary" @click="submitForm">确 定</el-button>-->
        <el-button @click="cancel">关闭</el-button>
      </div>
    </el-dialog>
  </div>
</template>

<script>
  import {mapGetters} from "vuex";
  import  router from 'vue-router'
  import {listMyUnreadNotice,getSysmessage,listSysmessage} from "@/api/system/sysmessage";
  import events from '@/utils/events'
  export default {
    name: "index",
    components: {},
    data() {
      return {
        noticeList: [],
        showAllBtn: false,
        form:{},
        rules:{},
        open:false,
        queryParams:{
          id:null,
          status:'0',
        }
      }
    },
    computed: {
      ...mapGetters(["isDot",'id']),
    },
    created() {
      this.getUnRead(); //查询是否有未读消息通知
      events.$on('noticePush', this.getUnRead)
      events.$on('noticePushByMsg', this.getUnRead)
      this.$nextTick(()=>{
        events.$on('noticeCheckByMsg', this.getUnRead)
      })
    },
    mounted() {
    },
    methods: {
      /** 查询是否存在未读消息 根据当前用户匹配消息表中得ID*/
      getUnRead() {
        this.queryParams.id = this.id
        listSysmessage(this.queryParams).then(res => {
          if(res.code == 200){
            if (res.rows.length>0) {
              let object = res.rows
              this.noticeList = object
              if(object.length >5){
                this.showAllBtn=true
              }else{
                this.showAllBtn=false
              }
              this.$store.dispatch('app/setIsDot', true)
            } else {
              this.noticeList = []
              this.$store.dispatch('app/setIsDot', false)
            }
          }
        });
      },
      bellClick() {
        this.getUnRead()
      },
      cancel(){
        this.open = false
        this.getUnRead();
      },
      //查看更多
      showAll() {
        this.$router.push({path: "/monitor/myMessage"});
      },
      //查看消息 弹窗显示
      handleRead(data){
        const messageId = data.messageId
        getSysmessage(messageId).then(response => {
          this.form = response.data;
          // this.form.messageTitle = data.messageTitle
          // this.form.messageContent = data.messageContent
          this.open = true

        });

      }
    }
  }
</script>

<style scoped>

</style>

把是否有消息的状态通过vuex存到公共状态里来管理

 

 

this.$store.dispatch('app/setIsDot', true) //设置红点

this.$store.dispatch('app/setIsDot', false) //去掉红点

 首先新建通知公告 发布通知

 我的消息列表

JAVA部分

两个表 通知公告表和我的消息表 做关联

发布消息根据指定的用户类型去插入数据 通过userID分别插入到我的消息表中

全部设置已读 首先去查未读的消息根据userID,在遍历集合更新状态