目录
一.Ajax
二.Axios
三.Vue
四.Element
五.增删改查案例
一.依赖：数据库，mybatis，servlet，json-对象转换器
二.资源：element+vue+axios
三.pojo
四.mapper.xml与mapper接口
五.service
六.servlet
七.html页面
建立web工程
需要的依赖：
<dependency><groupId>javax.servlet</groupId><artifactId>javax.servlet-api</artifactId><version>3.1.0</version></dependency><dependency><groupId>com.alibaba</groupId><artifactId>fastjson</artifactId><version>1.2.62</version></dependency>一.Ajax
AJAX(Asynchronous JavaScript And XML)：异步的js和xml 异步交互：与服务器交换数据并且更新部分网页的技术（局部刷新），操作无需等待服务器响应，直到数据响应回来才改变html页面 本案例使用ajax请求数据与处理响应数据，发送路径需要使用全路径
01ajax.html:
<!DOCTYPE html>
<html lang="en">
<head><meta charset="UTF-8"><title>Title</title>
</head>
<body>
</body>
<script>xhttp = new XMLHttpRequest();xhttp.open("GET", " http://localhost/web_demo5_ajax_war/ajaxServlet");xhttp.send();xhttp.onreadystatechange = function() {if (this.readyState == 4 && this.status == 200) {alert(this.responseText);}};
</script>
</html>@WebServlet("/ajaxServlet")
public class AJAXServlet extends HttpServlet {@Overrideprotected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {response.getWriter().write("Hello,AJAX!");}@Overrideprotected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {this.doGet(request, response);}
} 
二.Axios
Axios对原生的ajax封装，简化书写 使用准备：导入js文件，放到js文件里面，在本文件中引入js 本案例为使用axios用不同请求方式请求数据并处理响应数据
02axios.html:
<!DOCTYPE html>
<html lang="en">
<head><meta charset="UTF-8"><title>Title</title>
</head>
<body></body>
<script src="js/axios-0.18.0.js"></script>
<script>axios.get("http://localhost/web_demo5_ajax_war/axiosServlet?username=zhangsan").then(resp=>{alert(resp.data)})axios.post("http://localhost/web_demo5_ajax_war/axiosServlet","username=zhangsan").then(resp=>{alert(resp.data)})
</script>
</html>@WebServlet("/axiosServlet")
public class AxiosServlet extends HttpServlet {@Overrideprotected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {response.getWriter().write(request.getMethod());}@Overrideprotected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {this.doGet(request, response);}
}浏览器弹窗为两种不同的请求方式
三.Vue
Vue是一套前端的框架，在js中简化Dom操作 使用需要：导入vue.js1.改变框里面的值，对应的路径也改变1.绑定表单中的输入使用:v-model="url"2.绑定超链接跳转路径属性使用:v-bind:href="url"或:href="url"3.展示绑定模型的内容使用:{{}}} 2.点击按钮调用不同方法1.绑定事件元素使用:v-on:click="show()或者@click="show()"2.引入方法:在js的Vue模块中使用methods 3.通过输入展示不同标签1.if else：使用v-if="条件"属性2.展示内容与否:使用v-show标签 4.遍历模型：使用v-for=""属性在此案例中addr为局部变量名称，根据情况选择是否使用索引
<!DOCTYPE html>
<html lang="en">
<head><meta charset="UTF-8"><title>Title</title>
</head>
<body>
<div id="app"><input v-model="url"><br><a v-bind:href="url">{{url}}</a><br><a :href="url">{{url}}</a><br><br><br><input type="button" value="按钮1" v-on:click="show()"><br><input type="button" value="按钮2" @click="show()"><br><br><br><div v-if="count==1">div1</div><div v-else-if="count==2">div2</div><div v-else>div3</div><div v-show="count==4">div4</div><input v-model="count"><br><br><br><div v-for="addr in addrs">{{addr}}<br></div><div v-for="(addr,i) in addrs">{{i+1}}--{{addr}}<br></div>
</div>
<script src="js/vue.js"></script>
<script>new Vue({//创建vue核心对象el:"#app",//作用范围methods:{//方法show(){alert("按钮被点击")}},data(){//模型数据return {url:"https://www.baidu.com",count:1,addrs:["北京","上海","西安"]}},mounted(){//页面加载完成后的方法alert("加载完成")}})
</script>
</body>
</html> 
四.Element
1.复制粘贴element-ui文件 2.引文件使用：然后去官网复制粘贴即可
<!DOCTYPE html>
<html lang="en">
<head><meta charset="UTF-8"><title>Title</title></head>
<body>
<div id="app"><el-row><el-button>默认按钮</el-button><el-button type="primary">主要按钮</el-button><el-button type="success">成功按钮</el-button><el-button type="info">信息按钮</el-button><el-button type="warning">警告按钮</el-button><el-button type="danger">危险按钮</el-button></el-row>
</div>
</body>
<link rel="stylesheet" href="element-ui/lib/theme-chalk/index.css">
<script src="js/vue.js"></script>
<script src="element-ui/lib/index.js"></script>
<script>new Vue({el:"#app"})
</script>
</html>
五.增删改查案例
新建Web项目
一.依赖：数据库，mybatis，servlet，json-对象转换器
<dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>5.1.32</version></dependency><dependency><groupId>org.mybatis</groupId><artifactId>mybatis</artifactId><version>3.5.5</version></dependency><dependency><groupId>javax.servlet</groupId><artifactId>javax.servlet-api</artifactId><version>3.1.0</version><scope>provided</scope></dependency><dependency><groupId>com.alibaba</groupId><artifactId>fastjson</artifactId><version>1.2.62</version></dependency>二.资源：element+vue+axios
三.pojo
brand类中使用到了getStatusStr方法：由status返回字符串，交给别的类调用
public class Brand {private Integer id;private String brandName;private String companyName;private Integer ordered;private String description;private Integer status;public Brand() {}public Brand(Integer id, String brandName, String companyName, Integer ordered, String description, Integer status) {this.id = id;this.brandName = brandName;this.companyName = companyName;this.ordered = ordered;this.description = description;this.status = status;}public Integer getId() {return id;}public void setId(Integer id) {this.id = id;}public String getBrandName() {return brandName;}public void setBrandName(String brandName) {this.brandName = brandName;}public String getCompanyName() {return companyName;}public void setCompanyName(String companyName) {this.companyName = companyName;}public Integer getOrdered() {return ordered;}public void setOrdered(Integer ordered) {this.ordered = ordered;}public String getDescription() {return description;}public void setDescription(String description) {this.description = description;}public Integer getStatus() {return status;}public String getStatusStr(){if(this.status==1){ return "启用"; }return "禁用";}public void setStatus(Integer status) {this.status = status;}@Overridepublic String toString() {return "Brand{" +"id=" + id +", brandName='" + brandName + '\'' +", companyName='" + companyName + '\'' +", ordered=" + ordered +", description='" + description + '\'' +", status=" + status +'}';}
}
pagebean类用于存放一页的数据与总数量
public class PageBean<T> {private int totalCount;private List<T> rows;public PageBean() {}public PageBean(int totalCount, List<T> rows) {this.totalCount = totalCount;this.rows = rows;}public int getTotalCount() {return totalCount;}public void setTotalCount(int totalCount) {this.totalCount = totalCount;}public List<T> getRows() {return rows;}public void setRows(List<T> rows) {this.rows = rows;}
}
四.mapper.xml与mapper接口
使用到了批量删除、模糊查询、分页查询
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapperPUBLIC "-//mybatis.org//DTD Mapper 3.0//EN""http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="org.example.mapper.BrandMapper"><resultMap id="brandResultMap" type="Brand"><id column="id" property="id"/><result column="brand_name" property="brandName"/><result column="company_name" property="companyName"/></resultMap><delete id="deleteByIds">delete from tb_brand where id in<foreach collection="array" item="id" separator="," open="(" close=")">#{id}</foreach>;</delete><select id="selectByPageAndCondition" resultMap="brandResultMap">select *from tb_brand<where><if test="brand.status!=null">and status=#{brand.status}</if><if test="brand.companyName!=null and brand.companyName!=''">and company_name like #{brand.companyName}</if><if test="brand.brandName!=null and brand.brandName!=''">and brand_name like #{brand.brandName}</if></where>limit #{begin},#{size}</select><select id="selectCountByCondition" resultType="java.lang.Integer">select count(*) from tb_brand<where><if test="status!=null">and status=#{status}</if><if test="companyName!=null and companyName!=''">and company_name like #{companyName}</if><if test="brandName!=null and brandName!=''">and brand_name like #{brandName}</if></where></select>
</mapper>
public interface BrandMapper {//添加数据@Insert("insert into tb_brand values(null,#{brandName},#{companyName},#{ordered},#{description},#{status})")void add(Brand brand);//删除数据@Delete("delete from tb_brand where id=#{id}")void deleteById(int id);//更新数据@Update("update tb_brand set brand_name=#{brandName}," +"company_name=#{companyName}," +"ordered=#{ordered}," +"description=#{description}," +"status=#{status} " +"where id=#{id}")void update(Brand brand);//删除选中数据void deleteByIds(int[] ids);//条件分页查询int selectCountByCondition(Brand brand);List<Brand> selectByPageAndCondition(@Param("begin") int begin, @Param("size") int size, @Param("brand") Brand brand);}
五.service
public class BrandService {SqlSessionFactory factory = SqlSessionFactoryUtil.getssf();public void add(Brand brand) {SqlSession sqlsession=factory.openSession(true);sqlsession.getMapper(BrandMapper.class).add(brand);sqlsession.close();}public void deleteById(int id) {SqlSession sqlsession=factory.openSession(true);sqlsession.getMapper(BrandMapper.class).deleteById(id);sqlsession.close();}public void update(Brand brand) {SqlSession sqlsession=factory.openSession(true);sqlsession.getMapper(BrandMapper.class).update(brand);sqlsession.close();}public void deleteByIds(int[] ids) {SqlSession sqlsession=factory.openSession(true);sqlsession.getMapper(BrandMapper.class).deleteByIds(ids);sqlsession.close();}public PageBean<Brand> selectByPageAndCondition(int currentPage, int pageSize, Brand brand) {SqlSession sqlsession=factory.openSession(true);BrandMapper mapper=sqlsession.getMapper(BrandMapper.class);String brandName=brand.getBrandName();if(brandName!=null && !brandName.isEmpty()) brand.setBrandName("%"+brandName+"%");String companyName=brand.getCompanyName();if(companyName!=null && !companyName.isEmpty()) brand.setCompanyName("%"+companyName+"%");PageBean<Brand> pageBean=new PageBean<>(mapper.selectCountByCondition(brand),mapper.selectByPageAndCondition((currentPage-1)*pageSize,pageSize,brand));sqlsession.close();return pageBean;}
}六.servlet
服务类中使用反射判别不同的请求路径去访问不同方法
public class BaseServlet extends HttpServlet {@Overrideprotected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {String uri=req.getRequestURI();String methodName=uri.substring(uri.lastIndexOf('/')+1);Class<? extends BaseServlet> cls=this.getClass();try{Method method=cls.getMethod(methodName,HttpServletRequest.class,HttpServletResponse.class);method.invoke(this,req,resp);}catch (Exception e){e.printStackTrace();}}
}分页+模糊查询同时使用到了post+get方法
@WebServlet("/brand/*")
public class BrandServlet extends BaseServlet{private final BrandService service =new BrandService();public void add(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {System.out.println("add...");service.add(JSON.parseObject(request.getReader().readLine(),Brand.class));response.getWriter().write("success");}public void deleteById(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException{System.out.println("deleteById...");service.deleteById(Integer.parseInt(request.getParameter("id")));response.getWriter().write("success");}public void update(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException{System.out.print("update...");service.update(JSON.parseObject(request.getReader().readLine(),Brand.class));response.getWriter().write("success");}public void deleteByIds(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException{System.out.print("deleteMany...");service.deleteByIds(JSON.parseObject(request.getReader().readLine(),int[].class));response.getWriter().write("success");}//post+get方式来实现分页查询+条件查询，条件查询可有可无public void selectByPageAndCondition(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {System.out.println("brand selectByPageAndCondition...");response.setContentType("text/json;charset=UTF-8");response.getWriter().write(JSON.toJSONString(service.selectByPageAndCondition(Integer.parseInt(request.getParameter("currentPage")),Integer.parseInt(request.getParameter("pageSize")),JSON.parseObject(request.getReader().readLine(),Brand.class))));}
}
七.html页面
<!DOCTYPE html>
<html lang="en">
<head><meta charset="UTF-8"><title>Title</title>
</head>
<body>
<div id="app"><!--查询表单--><el-form :inline="true" :model="brandSelect" class="demo-form-inline"><el-form-item label="当前状态"><el-select v-model="brandSelect.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="brandSelect.companyName" placeholder="企业名称"></el-input></el-form-item><el-form-item label="品牌名称"><el-input v-model="brandSelect.brandName" placeholder="企业名称"></el-input></el-form-item><el-form-item><el-button type="primary" @click="selectAll">查询</el-button></el-form-item></el-form><!--新增与批量删除按钮--><el-row><el-button type="danger" plain @click="deleteByIds">批量删除</el-button><el-button type="primary" plain @click="handleAdd">新增</el-button></el-row><!--添加数据与修改数据的对话框表单--><el-dialogtitle="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-color="#13ce66"inactive-color="#ff4949"active-value="1"inactive-value="0"></el-switch></el-form-item><!--点击事件设立一下--><el-form-item><template v-if="method=='修改'"><el-button type="primary" @click="updateBrand">提交修改</el-button></template><template v-else><el-button type="primary" @click="addBrand">提交添加</el-button></template><el-button @click=cancelUpdate>取消</el-button></el-form-item></el-form></el-dialog><!--表格--><el-table:data="tableData"style="width: 100%"stripe@selection-change="handleSelectionChange"><el-table-columntype="selection"></el-table-column><el-table-columnlabel="排序"type="index"></el-table-column><el-table-columnprop="brandName"label="品牌名称"align="center"></el-table-column><el-table-columnprop="companyName"label="企业名称"align="center"></el-table-column><el-table-columnprop="ordered"align="center"label="排序"></el-table-column><!--取值为statusStr，找到Brand里面的对应的get方法--><el-table-columnprop="statusStr"align="center"label="当前状态"></el-table-column><el-table-column label="操作" align="center"><template slot-scope="scope"><el-buttontype="primary"@click="handleEdit(scope.$index, scope.row)">编辑</el-button><el-buttontype="danger"@click="handleDelete(scope.$index, scope.row)">删除</el-button></template></el-table-column></el-table><!--分页--><el-pagination@size-change="handleSizeChange"@current-change="handleCurrentChange":current-page="currentPage":page-sizes="[5, 10, 15, 20]":page-size="100"layout="total, sizes, prev, pager, next, jumper":total="totalCount"></el-pagination>
</div>
<script src="js/axios-0.18.0.js"></script>
<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>new Vue({el: "#app",mounted() {this.selectAll();},data() {return {//表内数据与查询的数据tableData: [],brandSelect: {status: '',brandName: '',companyName: '',description: '',id: '',ordered: '',},//add与update表单显示开关，方法选择，使用的模型dialogVisible: false,method: '',brand: {},//复选框数据，选中的要删除的数据multipleSelection: [],selectedIds: [],//分页数据pageSize: 5,totalCount: 100,currentPage: 1,}},methods: {//添加功能与修改功能handleAdd() {this.method = '添加';this.brand = {status: '',brandName: '',companyName: '',description: '',id: '',ordered: '',};this.dialogVisible = true},handleEdit(index, row) {this.method = '修改'this.brand = this.tableData[index];this.brand.status = String(this.brand.status)this.dialogVisible = true;},addBrand() {axios.post("http://localhost/web_demo6_war/brand/add", this.brand).then(resp => {if (resp.data == "success") {this.dialogVisible = false;this.$message({message: '添加成功',type: 'success'});this.selectAll();}})},updateBrand() {axios.post("http://localhost/web_demo6_war/brand/update", this.brand).then(resp => {if (resp.data == "success") {this.dialogVisible = false;this.$message({message: '修改成功',type: 'success'});this.selectAll();}})},cancelUpdate() {this.dialogVisible = falsethis.$message({message: '已取消修改',});this.selectAll()},//删除功能handleDelete(index, row) {this.$confirm('此操作将永久删除改公司信息, 是否继续?', '提示', {confirmButtonText: '确定',cancelButtonText: '取消',type: 'warning'}).then(() => {axios.get("http://localhost/web_demo6_war/brand/deleteById?id=" + this.tableData[index].id).then(resp => {if (resp.data == "success") {this.$message({message: '删除成功',type: 'success'});this.selectAll();}})}).catch(() => {this.$message({type: 'info',message: '已取消删除'});});},//批量删除功能handleSelectionChange(val) {this.multipleSelection = val;console.log(this.multipleSelection);},deleteByIds() {for (let i = 0; i < this.multipleSelection.length; i++) {let selectedElement = this.multipleSelection[i];this.selectedIds[i] = selectedElement.id;}this.$confirm('此操作将永久删除改公司信息, 是否继续?', '提示', {confirmButtonText: '确定',cancelButtonText: '取消',type: 'warning'}).then(() => {if (this.selectedIds.length != 0) {axios.post("http://localhost/web_demo6_war/brand/deleteByIds", this.selectedIds).then(resp => {if (resp.data == "success") {this.$message({message: '删除成功',type: 'success'});this.selectAll();}})this.selectedIds = [];} else {this.$message({message: '需要选中几个数据',type: 'warning'});}}).catch(() => {this.$message({type: 'info',message: '已取消删除'});});},//分页工具条方法handleSizeChange(val) {console.log(`每页 ${val} 条`);this.pageSize = val;this.selectAll();},handleCurrentChange(val) {console.log(`当前页: ${val}`);this.currentPage = val;this.selectAll();},//查询分页：selectAll() {axios.post("http://localhost/web_demo6_war/brand/selectByPageAndCondition?currentPage=" + this.currentPage + "&pageSize=" + this.pageSize,this.brandSelect).then(resp => {this.tableData = resp.data.rows;this.totalCount = resp.data.totalCount;console.log(this.tableData);})},}})
</script>
</body>
</html> 
在本文的最后，说一些最近的感想：
学习这类技术似乎不能太认真，或许会浪费大把的时间
“作数”或许就行了！
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