目录（不想看分析的可以直接到解决方案处找答案）

项目场景：

提示：黑马新版web最后一个项目，增删改查的删除操作

问题描述

难点：如何获取每一行的id传到servlet

在BrandMapper中使用Delete注解进行删除操作，需要返回id，大多数人都无法找到

    /**
     * 删除数据
     *
     * @param id
     */
    @Delete("delete from tb_brand where id=#{id}")
    void deleteId(int id);

错因分析：

提示：作为一个后端人员，后端代码都不难，所以附在后面，不详解。

只详细讲解前端获取id并返回的操作

axios({
                        method: "post",
                        url: "http://localhost:8080/brand-case/brand/deleteId",
                        data: this.brand.id
                    })

传入brand的id无法获取，在servlet打印params显示数据为null

解决方案：

（前端获取id方法，需要后端传递id的代码可留言获取）

1加入(scope.$index, scope.row)获取每行信息

<el-button type="primary" plain @click="handleEdit(scope.$index, scope.row)">修改</el-button>
<el-button type="danger" plain @click="deleteId(scope.$index, scope.row)">删除</el-button>

2.method的delete方法传参

deleteId(index, row)

3.在axios异步请求data处修改data: row.id（请求方式为post）

axios({
                        method: "post",
                        url: "http://localhost:8080/brand-case/brand/deleteId",
                        data: row.id
                    })

这样就可以把每行的id返回去了

此时再次在servlet打印params显示数据为所删除数据的id，id就获取到了

单独删除操作的所有html代码：

<el-row>
<el-button type="primary" plain @click="handleEdit(scope.$index, scope.row)">修改</el-button>
<el-button type="danger" plain @click="deleteId(scope.$index, scope.row)">删除</el-button>
</el-row>

// 删除数据
            deleteId(index, row) {
                var _this = this;
                //发送ajax异步请求，删除数据
                this.$confirm('此操作将永久删除该文件, 是否继续?', '提示', {
                    confirmButtonText: '确定',
                    cancelButtonText: '取消',
                    type: 'warning'
                }).then(() => {
                    axios({
                        method: "post",
                        url: "http://localhost:8080/brand-case/brand/deleteId",
                        data: row.id
                    }).then(function (resp) {
                        if (resp.data == "success") {
                            //查询一次
                            _this.selectAll();
                            _this.$message({
                                message: '恭喜你，删除数据成功',
                                type: 'success'
                            });
                        } else {
                            _this.$message.error('删除数据失败，别玩了退游吧，捏麻麻滴');
                        }
                    })
                }).catch(() => {
                    this.$message({
                        type: 'info',
                        message: '已取消删除'
                    });
                });
            },

附上项目完成后的全部html代码

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        .el-table .warning-row {
            background: oldlace;
        }

        .el-table .success-row {
            background: #f0f9eb;
        }
    </style>

</head>
<body>
<div id="app">

    <!--搜索表单-->
    <el-form :inline="true" :model="brand" class="demo-form-inline">

        <el-form-item label="当前状态">
            <el-select v-model="brand.status" placeholder="当前状态">
                <el-option label="启用" value="1"></el-option>
                <el-option label="禁用" value="0"></el-option>
            </el-select>
        </el-form-item>

        <el-form-item label="企业名称">
            <el-input v-model="brand.companyName" placeholder="企业名称"></el-input>
        </el-form-item>

        <el-form-item label="品牌名称">
            <el-input v-model="brand.brandName" placeholder="品牌名称"></el-input>
        </el-form-item>

        <el-form-item>
            <el-button type="primary" @click="onSubmit">查询</el-button>
        </el-form-item>
    </el-form>

    <!--按钮-->

    <el-row>

        <el-button type="danger" plain @click="deleteByIds">批量删除</el-button>
        <el-button type="primary" plain @click="dialogVisible = true">新增</el-button>

    </el-row>
    <!--添加数据对话框表单-->
    <el-dialog
            title="编辑品牌"
            :visible.sync="dialogVisible"
            width="30%"
    >

        <el-form ref="form" :model="brand" label-width="80px">
            <el-form-item label="品牌名称">
                <el-input v-model="brand.brandName"></el-input>
            </el-form-item>

            <el-form-item label="企业名称">
                <el-input v-model="brand.companyName"></el-input>
            </el-form-item>

            <el-form-item label="排序">
                <el-input v-model="brand.ordered"></el-input>
            </el-form-item>

            <el-form-item label="备注">
                <el-input type="textarea" v-model="brand.description"></el-input>
            </el-form-item>

            <el-form-item label="状态">
                <el-switch v-model="brand.status"
                           active-value="1"
                           inactive-value="0"
                ></el-switch>
            </el-form-item>


            <el-form-item>
                <el-button @click="addBrand" type="primary">提交</el-button>
                <el-button @click="dialogVisible = false">取消</el-button>
            </el-form-item>
        </el-form>

    </el-dialog>


    <!--表格-->
    <template>
        <el-table
                :data="tableData"
                style="width: 100%"
                :row-class-name="tableRowClassName"
                @selection-change="handleSelectionChange"
        >
            <el-table-column
                    type="selection"
                    width="55">
            </el-table-column>
            <el-table-column
                    type="index"
                    width="50">
            </el-table-column>

            <el-table-column
                    prop="brandName"
                    label="品牌名称"
                    align="center"
            >
            </el-table-column>
            <el-table-column
                    prop="companyName"
                    label="企业名称"
                    align="center"
            >
            </el-table-column>
            <el-table-column
                    prop="ordered"
                    align="center"
                    label="排序">
            </el-table-column>
            <el-table-column
                    prop="status"
                    align="center"
                    label="当前状态">
            </el-table-column>

            <el-table-column
                    align="center"
                    label="操作">

                <!--
                                <el-row>
                                    <el-button type="primary">修改</el-button>
                                    <el-button type="danger" plain @click="deleteId">删除</el-button>
                                </el-row>
                -->
                <!--size="mini"-->
                <template slot-scope="scope">
                    <el-button type="primary" plain @click="handleEdit(scope.$index, scope.row)">修改</el-button>
                    <el-button type="danger" plain @click="deleteId(scope.$index, scope.row)">删除</el-button>


                    <!--                &lt;!&ndash;修改数据对话框表单&ndash;&gt;-->
                    <el-dialog

                            title="修改品牌信息"
                            :visible.sync="centerVisible"
                            width="30%">

                        <el-form ref="form" :model="brand" label-width="80px">

                            <el-form-item label="品牌名称">
                                <el-input v-model="brand.brandName"></el-input>
                            </el-form-item>

                            <el-form-item label="企业名称">
                                <el-input v-model="brand.companyName"></el-input>
                            </el-form-item>

                            <el-form-item label="排序">
                                <el-input v-model="brand.ordered"></el-input>
                            </el-form-item>

                            <el-form-item label="备注">
                                <el-input type="textarea" v-model="brand.description"></el-input>
                            </el-form-item>

                            <el-form-item label="状态">
                                <el-switch v-model="brand.status"
                                           active-value="1"
                                           inactive-value="0"
                                ></el-switch>
                            </el-form-item>


                            <el-form-item>
                                <el-button @click="edit()" type="primary">提交</el-button>
                                <el-button @click="centerVisible = false">取消</el-button>
                            </el-form-item>
                        </el-form>

                    </el-dialog>
                </template>

            </el-table-column>

        </el-table>
    </template>

    <!--分页工具条-->
    <el-pagination
            @size-change="handleSizeChange"
            @current-change="handleCurrentChange"
            :current-page="currentPage"
            :page-sizes="[5, 10, 15, 20]"
            :page-size="5"
            layout="total, sizes, prev, pager, next, jumper"
            :total="totalCount">
    </el-pagination>

</div>


<script src="js/vue.js"></script>
<script src="element-ui/lib/index.js"></script>
<link rel="stylesheet" href="element-ui/lib/theme-chalk/index.css">
<script src="js/axios-0.18.0.js"></script>

<script>
    new Vue({
        el: "#app",
        mounted() {
            this.selectAll();
        },
        methods: {
            //查询分页数据
            selectAll() {
                axios({
                    method: "post",
                    url: "http://localhost:8080/brand-case/brand/selectByPageAndCondition?currentPage=" + this.currentPage + "&pageSize=" + this.pageSize,
                    data: this.brand
                }).then(resp=>{
                    //设置表格数据
                    this.tableData = resp.data.rows;
                    //表格总数
                    this.totalCount = resp.data.totalCount;
                    }
                )
                /*var _this = this;
                axios({
                    method: "post",
                    url: "http://localhost:8080/brand-case/brand/selectByPageAndCondition?currentPage=" + this.currentPage + "&pageSize=" + this.pageSize,
                    data: this.brand
                }).then(function (resp) {
                    //设置表格数据
                    _this.tableData = resp.data.rows;
                    //表格总数
                    _this.totalCount = resp.data.totalCount;
                })*/
            },
            tableRowClassName({row, rowIndex}) {
                if (rowIndex === 1) {
                    return 'warning-row';
                } else if (rowIndex === 3) {
                    return 'success-row';
                }
                return '';
            },
            // 复选框选中后执行的方法
            handleSelectionChange(val) {
                this.multipleSelection = val;
                console.log(this.multipleSelection);
                //console.log(this.multipleSelection)
            },
            // 查询方法
            onSubmit() {
                //console.log(this.brand);
                this.selectAll();

            },
            // 添加数据
            addBrand() {

                //console.log(this.brand);
                var _this = this;
                //发送ajax异步请求，添加数据
                axios({
                    method: "post",
                    url: "http://localhost:8080/brand-case/brand/add",
                    data: _this.brand
                }).then(function (resp) {
                    if (resp.data == "success") {
                        //关闭窗口
                        _this.dialogVisible = false;
                        //查询一次
                        _this.selectAll();
                        _this.$message({
                            message: '恭喜你，添加数据成功',
                            type: 'success'
                        });
                    } else {
                        _this.$message.error('添加数据失败，请将排序改为数字，否则会受异次元力量的影响无法添加');
                    }
                })
            },
            handleEdit(index, row) {
                console.log(index, row);
                this.brand.id = row.id;
                this.centerVisible = true;
            },
            //修改数据的部分内容
            edit() {
                //console.log(this.brand);
                var _this = this;
                //发送ajax异步请求，添加数据
                axios({
                    method: "post",
                    url: "http://localhost:8080/brand-case/brand/edit",
                    data: _this.brand,
                }).then(function (resp) {
                    if (resp.data == "success") {
                        //关闭窗口
                        _this.centerVisible = false;
                        //查询一次
                        _this.selectAll();
                        _this.$message({
                            message: '恭喜你，修改数据成功',
                            type: 'success'
                        });
                    } else {
                        _this.$message.error('修改数据失败，请将排序改为数字，否则会受异次元力量的影响无法修改');
                    }
                })
            },

            // 删除数据
            deleteId(index, row) {
                var _this = this;
                //发送ajax异步请求，删除数据
                this.$confirm('此操作将永久删除该文件, 是否继续?', '提示', {
                    confirmButtonText: '确定',
                    cancelButtonText: '取消',
                    type: 'warning'
                }).then(() => {
                    axios({
                        method: "post",
                        url: "http://localhost:8080/brand-case/brand/deleteId",
                        data: row.id
                    }).then(function (resp) {
                        if (resp.data == "success") {
                            //查询一次
                            _this.selectAll();
                            _this.$message({
                                message: '恭喜你，删除数据成功',
                                type: 'success'
                            });
                        } else {
                            _this.$message.error('删除数据失败，别玩了退游吧，捏麻麻滴');
                        }
                    })
                }).catch(() => {
                    this.$message({
                        type: 'info',
                        message: '已取消删除'
                    });
                });
            },
            //批量删除
            deleteByIds() {
                //创建数组ID

                //从this.multipleSelection获取
                for (let i = 0; i < this.multipleSelection.length; i++) {
                    let selectionElement = this.multipleSelection[i];
                    this.selectedIds[i] = selectionElement.id;
                }

                //发送ajax请求
                var _this = this;
                //发送ajax异步请求，删除数据
                this.$confirm('此操作将永久删除该文件, 是否继续?', '提示', {
                    confirmButtonText: '确定',
                    cancelButtonText: '取消',
                    type: 'warning'
                }).then(() => {
                    axios({
                        method: "post",
                        url: "http://localhost:8080/brand-case/brand/deleteByIds",
                        data: _this.selectedIds
                    }).then(function (resp) {
                        if (resp.data == "success") {
                            //查询一次
                            _this.selectAll();
                            _this.$message({
                                message: '恭喜你，批量删除数据成功',
                                type: 'success'
                            });
                        } else {
                            _this.$message.error('批量删除数据失败，你干了啥奇怪的事，捏麻麻滴');
                        }
                    })
                }).catch(() => {
                    this.$message({
                        type: 'info',
                        message: '已取消删除'
                    });
                });

            },

            //分页
            handleSizeChange(val) {
                //每页显示条数
                this.pageSize = val;
                this.selectAll();
            },
            handleCurrentChange(val) {
                //console.log(`当前页: ${val}`);
                this.currentPage = val;
                this.selectAll();

            }

        },
        data() {
            return {
                //总记录数
                totalCount: 100,
                // 当前页码
                currentPage: 1,
                //每页显示的条数
                pageSize: 5,
                // 添加数据对话框是否展示的标记
                dialogVisible: false,
                centerVisible: false,
                // 品牌模型数据
                brand: {
                    id: "",
                    brandName: '',
                    companyName: '',
                    ordered: "",
                    description: "",
                    status: ''
                },
                //被选中的id数组
                selectedIds: [],
                // 复选框选中数据集合
                multipleSelection: [],
                // 表格数据
                tableData: [{
                    brandName: '华为',
                    companyName: '华为科技有限公司',
                    ordered: '100',
                    status: "1"
                }, {
                    brandName: '华为',
                    companyName: '华为科技有限公司',
                    ordered: '100',
                    status: "1"
                }, {
                    brandName: '华为',
                    companyName: '华为科技有限公司',
                    ordered: '100',
                    status: "1"
                }, {
                    brandName: '华为',
                    companyName: '华为科技有限公司',
                    ordered: '100',
                    status: "1"
                }]
            }
        },

    })

</script>

</body>
</html>

黑马Web项目的删除操作如何获取Id