未整理的杂项

<form id="form1" action="${pageContext.request.contextPath}/ProductUpd">
    <input type="hidden" name="id" id="id1">
    <div class="input-group offset-1 col-10">
        <div class="input-group-prepend">
            <span class="input-group-text">编号</span>
        </div>
        <input type="number" class="form-control" name="product_no" id="bianhao">
        <div class="input-group-prepend">
            <span class="input-group-text">名称</span>
        </div>
        <input type="text" class="form-control" name="product_name" id="mingcheng">
    </div>
    <div class="input-group offset-1 col-10">
        <div class="input-group-prepend">
            <span class="input-group-text">类型</span>
        </div>
        <input type="text" class="form-control" name="product_type" id="leixing">
        <div class="input-group-prepend">
            <span class="input-group-text">状态</span>
        </div>
        <select class="form-control" name="status" id="zhuantai">
            <option value="1">有效</option>
            <option value="2">无效</option>
        </select>
    </div>
</form>

$(function(){
    $("#submit1").click(function(){
        $.ajax({
            url: "${pageContext.request.contextPath}/ProductUpd",
            type: "post",
            data: $("#form1").serialize(),　　//为了记录这个
            success: function(result){
                if(result==1){
                    alert("产品信息修改成功！");
                }
            },
            error: function(){
                alert("异常！");
            }
        });
    });
});

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    int id = Integer.parseInt(request.getParameter("id"));
    try {
        ObjectMapper mapper = new ObjectMapper();
        Product product = productService.selectById(id);
        String jsonString  = mapper.writeValueAsString(product);
        response.setCharacterEncoding("utf-8");
        response.getWriter().print(jsonString);
        //response.getWriter().write(jsonString);
    } catch (Exception e) {
        e.printStackTrace();
    }
}

<style type="text/css">
    .father{
        width: 300px;
        height: 300px;
        background-color: black;
        position: absolute;
        top:50%;
        left:50%;
        margin-top: -150px;
        margin-left: -150px;
    }
    .son{
        /* 相对于父级元素相对后的位置进行定位，父级元素需要relative(通常)或absolute或fixed*/
        width: 100px;
        height: 100px;
        background-color: pink;
        position: absolute;
        left:0;
        top:0;
    }

</style>


<div class="father">
   <div class="son"></div>
</div>

<!-- 添加图标，另外font-awesome使用的时候，不能只用font-awesom，需要带着所有文件 -->

<style type="text/css">    /* 用font-awesome添加图标，4.3后好像就不用这样了，改成自带 */
    .valid-feedback.feedback-icon,
.invalid-feedback.feedback-icon {
    position: absolute;
    width: auto;
    bottom: 10px;
    right: 10px;
    margin-top: 0;
}
</style>

<div class="container">
    <div class="form-group position-relative">
        <label for="input2">Valid with icon</label>
        <input type="text" class="form-control is-valid" id="input2">
        <div class="valid-feedback feedback-icon">
            <i class="fa fa-check"></i>
        </div>
    </div>
    <div class="form-group position-relative">  
        <label for="input3">inValid with icon</label>
        <input type="text" class="form-control is-invalid" id="input3">
　　　　　<!-- 一个icon对应于一个父级的position-relative，
　　　　　是relative在起作用不是form-control -->
        <div class="invalid-feedback feedback-icon">
            <i class="fa fa-times"></i>
        </div>
    </div>
</div>

<tbody>
    <c:forEach var="product" items="${requestScope.list}">
        <tr>
            <td
                style="max-width: 100px; overflow: hidden; text-overflow: ellipsis; white-space: nowrap">${product.product_no}</td>
            <td>${product.product_name}</td>
            <td>${product.product_type}</td>
            <td id="${product.id}">${product.status==1?"有效":"无效"}</td>
            <td><button class="btn btn-primary pb-1 pt-1" onclick="shanchu(${product.id})">删除</button></td>
            <td><button type="button" class="btn btn-primary" onclick="xiugai(${product.id})">修改</button></td>
        </tr>
    </c:forEach>
</tbody>

<script type="text/javascript">
    function shanchu(id){
         let msg = "确定要删除本条产品信息吗？"; 
         if (confirm(msg)){ 
             location.href="${pageContext.request.contextPath}/del?id="+id;
         } 
    }
    
    function xiugai(id){
        $.ajax({
            url : "${pageContext.request.contextPath}/ProductJsonId",
            type : "post",
            data : {
                id : id
            },
            success : function(str) {
                let obj = JSON.parse(str);
                $("#id1").val(obj.id);
                $("#bianhao").val(obj.product_no);
                $("#mingcheng").val(obj.product_name);
                $("#leixing").val(obj.product_type);
                if(obj.status==1){
                    $("#zhuantai").val("1");
                }else{
                    $("#zhuantai").val("2");
                }
                $("#myModal").modal();　　//显示模态框
            }
        }); 
    }
</script>

<form action="${pageContext.request.contextPath}/sendtojsp" method="post" >
    <label for="comment">填写意见:</label>
    <textarea name="detail" required class="form-control" rows="3" id="comment" style="resize: none;"></textarea>
    <div class="btn-group d-flex">　　<!--需要先定义出弹性盒子-->
        <input name="" type="submit" class="btn btn-outline-success flex-fill m-2" value="提交">
        <input name="" type="reset" class="btn btn-outline-danger flex-fill m-2" value="重写">
    </div>
</form>

<ul class="pagination justify-content-center">
    <c:forEach var="i" begin="1" end ="${pages.num}">
        <li class="page-item"><a class="page-link" href="${省略}/result?page=${i}">第${i}页</a></li>
    </c:forEach>
</ul>

public void doFilter(ServletRequest req, ServletResponse resp,
        FilterChain chain) throws IOException, ServletException {
    HttpServletRequest request = (HttpServletRequest) req;
    HttpServletResponse response = (HttpServletResponse) resp;
    String encoding = config.getInitParameter("encoding");
    
    if (encoding != null) {
        response.setContentType("text/html ;charset=" + encoding);
        request.setCharacterEncoding(encoding);
        response.setCharacterEncoding(encoding);
        //response的设值一定要在doFilter之前，否则，当后台
        //resp.getWriter().write("abc");时，这一段abc是不受utf-8的管制的，
        //相当于先传值后设置字符集，对于一开始传的值无效，对后边的应该有效
    }
    chain.doFilter(request, response);
}

<div class="row align-content-center justify-content-center" style="height:100vh">

<div class="container">
    <h1 align="center">XX</h1>
    <div class="row">　　　　<!--行-->
        <div class="col-10" style="border: 1px solid #000">　　<!--列-->
            <form>
                <div class="form-row">　　<!--内部在分行-->
                    <div class="col-6">
                        <input type="text" class="form-control">
                    </div>
                    <div class="col-6">
                        <input type="text" class="form-control">
                    </div>
                </div>
                <div class="form-row mt-3">
                    <div class="col-6">
                        <input type="text" class="form-control">
                    </div>
                    <div class="col-6">
                        <input type="text" class="form-control">
                    </div>
                </div>
            </form>
        </div>
        <!--列，这里上面的列一共占据两行，使得最外层的行变粗，变成了两行，这里col-2自然也占据一个变粗后的行的两列-->
        <div class="col-2 d-flex justify-content-center flex-wrap align-content-center" style="border: 1px solid #f00">
                <button id="sub" type="button" class="btn btn-outline-success"> 预 定 </button>
        </div>
        
    </div>
</div>

body{
      background:#fff url("images/login.jpg") no-repeat left top;
      background-size:cover;
}

<script type="text/javascript">

    $.validator.setDefaults( {
        submitHandler: function (form) {
            alert( "submitted!" );
            form.submit();
        }
    } );

    $(function(){
            $("#form").validate({
            rules: {
                reachDate: { //对应的是表单元素的name属性的值，即name="reacheDate"
                    required: true
                },
                leaveDate: {
                    required: true
                },
                roomRateId: {
                    required: true
                },
                roomCount: {
                    required: true
                }
            },
            messages: {
                reachDate: "请选择入住日期",
                leaveDate: "请选择离开日期",
                roomRateId: "请选择房间类型",
                roomCount: "请选择房间数目"
            },
            errorElement: "em",
            errorPlacement: function ( error, element ) {
                // Add the `invalid-feedback` class to the error element
                error.addClass( "invalid-feedback" );

                if ( element.prop( "type" ) === "checkbox" ) {
                    error.insertAfter( element.next( "label" ) );
                } else {
                    error.insertAfter( element );
                }
　　　　　　　　　　//error为校验失败创建的信息提示标签，element为当前被校验的控件
            },
            highlight: function ( element, errorClass, validClass ) {
                $( element ).addClass( "is-invalid rounded-right" ).removeClass( "is-valid" );
　　　　　　　　　　//rounded-right，让右边的框角变成圆的，看情况加
            },
            unhighlight: function (element, errorClass, validClass) {
                $( element ).addClass( "is-valid" ).removeClass( "is-invalid" );
            }
        });
    });

    $(function(){
        $("#sub").click(function(){
            $("#form").submit();
        });
    });
        
</script>

$(document).ready(function () {
    $("#totop").hide();
    $(function () {
        $(window).scroll(function () {
            if ($(window).scrollTop() > 20) {
                $("#totop").fadeIn(500);
            } else {
                $("#totop").fadeOut(500);
            }
        });
        $("#totop").click(function () {
            $('body,html').animate({
                scrollTop: 0
            }, 500);
        });
    });
});

<p id="totop">
    <a href="#">
        <span class="glyphicon glyphicon-chevron-up"></span>
    </a>
</p>

p #totop {
    position: fixed;
    bottom: 18px;
    right: 12px;
}

p #totop a {
    text-align: center;
    text-decoration: none;
    color: #000;
    display: block;
    width: 30px;
    /*使用CSS3中的transition属性给跳转链接中的文字添加渐变效果*/
    -moz-transition: color1s;
    -webkit-transition: color1s;
    -o-transition: color1s;
}

p #totop a:hover {
    color: #000011;
}

p #totop a span {
    background-color: #d4bbbb;
    z-index: -100;
    border: 1px solid #cccccc;
    border-radius: 6px;
    display: block;
    height: 30px;
    width: 30px;
    padding-top: 5px;
    /*使用CSS3中的transition属性给<span>标签背景颜色添加渐变效果*/
    -moz-transition: background1s;
    -webkit-transition: background1s;
    -o-transition: background1s;
}

#totop a:hover span {
    background-color: #f0f0f0;
}

<!-- 假设request中type为'按钮'，id为1，name为jack -->
<input type="button" value="${type}" onclick="fn(${id}, '${name}')">

String msg = "hello";
response.getWriter().print("<script>alert('"+msg+"');location.href='productController';</script>");

public class asdf {
    
    public asdf(String str1, String str2) {
        System.out.println("str");
    }
    
    public asdf(String str) {
        this(str, null);    //正确，优先匹配子类？，null比较特殊
                    //如果把下面的构造改成Integer则不行，
                //改成Integer后，这一行会报靠上的一个构造函数的错误
            //例如这里报String String ambiguous，当然如果类型相同则直接找类型相同的
    }
    
    public asdf(String str1, Object str2) {
        System.out.println("obj");
    }
    
    public static void main(String[] args) {
        new asdf(null);
    }
}

public class asdf {
    
    public asdf(String str1, Test str2) {
        System.out.println("str");
    }
    
    public asdf(String str) {
        this(str, null);
    }
    
    public asdf(String str1, Test2 str2) {
        System.out.println("obj");
    }
    
    public static void main(String[] args) {
        Test test = new Test2();
        new asdf("123", test); //输出str，说明，函数中参数传递时，依靠引用（指针）的类型
                                //但getClass()获取的是实际堆中对象的类型
        System.out.println(test.getClass());
        System.out.println(test instanceof Test2);
    }
}

class Test{
    public Test() {
        
    }
}

class Test2 extends Test{
    public Test2() {
        
    }
}

class Test{
    public void print() {
        System.out.println("可以调用");
    }
}
//下面是main方法中
((Test)null).print();
上面的内容不会报错，但是运行时会报空指针异常java.lang.NullPointerException

<form  class="form-inline justify-content-center">
    <div class="form-group mr-2">
        <label for="exampleInputName2">Id：</label>
        <input type="text" class="form-control" name="id" id="exampleInputName2">
    </div>
    <div class="form-group mr-2">
        <label for="exampleInputEmail2">Name：</label>
        <input type="text" class="form-control" name="name" id="exampleInputEmail2">
    </div>
    <button type="button" class="btn btn-primary" @click="getAllList">搜索</button>
</form>

getAllList(){
    this.$http.get("Vue").then(result=>{      
        alert("zhixingle");
        alert(result.url);
        this.list = result.body;
        alert(result.body);
    })
}