Call Java methods in js

In JavaScript you want to call Java methods, I visited servlet via JavaScript, then Java method of a class by calling servlet.

HTML code

<table id="cartTable">
    <thead>
        <tr>
            <th class="product_remove">
                <label>
                    <input class="check-all check" type="checkbox"/>&nbsp;&nbsp;全选
                </label>
                <a class="fl delete" id="deleteAll" href="javascript:;"><i class="fa fa-trash-o"></i></a>
            </th>
            <th class="product_thumb">图片</th>
            <th class="product_name">名称</th>
            <th class="product-price">价格</th>
             <th class="product_quantity">款式</th>
       </tr>
    </thead>
    <tbody>
        <tr>
            <td class="product_remove">
                <input class="check-one check" type="checkbox"/>
            </td>
            <td class="product_thumb">
                <a href="ShopShoesDetails.jsp?shoes_id=<%=shoes.getShoes_id() %>">
                    <img src="${pageContext.request.contextPath}/ShopServlet?method=getShopsShoesImage&shoes_id=<%=shoes.getShoes_id() %>" alt="">
               </a>
            </td>
            <td class="product_name">
                <a href="ShopShoesDetails.jsp?shoes_id=<%=shoes.getShoes_id() %>"><%=shoes.getBrand() %>/<%=shoes.getSeries() %>/<%=shoes.getName() %>
                </a>
            </td>
            <td class="product-price"><%=shoes.getPrice() %></td>
            <td class="product_quantity"><%=shoes.getSex() %>/<%=shoes.getSize() %></td>
        </tr>
    </tbody>
</table> 

 

ShopShoesDao.java

public void deleteFromCart(String shoes_id) {
        System.out.println("ShopShoesDao.deleteFromCart");
        String[] shoes_ids = shoes_id.split(",");
        
        Connection connection = DBUtil.getConnection();
        PreparedStatement preparedStatement = null;
        
        try {
            for (String string : shoes_ids) {
                int id = Integer.parseInt(string);
                String sql = "delete from user_product_cart where shoes_id = ?";
                preparedStatement = connection.prepareStatement(sql);
                preparedStatement.setInt(1, id);
                preparedStatement.executeUpdate();
            }
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }finally {
            DBUtil.close(preparedStatement);
            DBUtil.close(connection);
        }
    }

 

ShopServlet.java

protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        System.out.println("service");
        request.setCharacterEncoding("UTF-8");
        String method=request.getParameter("method");
        System.out.println(method);
        if(method.equals("addProduct")) {
            addProduct(request,response);
        }else if(method.equals("getShopsShoesImage")) {
            try {
                getShopsShoesImage(request,response);
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }else if(method.equals("addToCart")) {
            try {
                addToCart(request, response);
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }else if(method.equals("deleteFromCart")) {
            try {
                deleteFromCart(request, response);
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }else if(method.equals("payFromCart")) {
            try {
                payFromCart(request, response);
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
    }
private void deleteFromCart(HttpServletRequest request, HttpServletResponse response) throws IOException, SQLException {
        // TODO Auto-generated method stub
        System.out.println("deleteFromCart");
        request.setCharacterEncoding("UTF-8");
        int user_id= Integer.parseInt(request.getParameter("user_id"));
        System.out.println(user_id);
        String shoes_id = request.getParameter("shoes_id");
        System.out.println(shoes_id);
        ShopShoesDao shopShoesDao = new ShopShoesDao();
        shopShoesDao.deleteFromCart(shoes_id);
        request.getSession().setAttribute("shoes_id", shoes_id);
        response.sendRedirect(request.getContextPath()+"/cart.jsp");
    }

 

javascrip Code 

// click Remove All 
    deleteAll.onclick = function () {
         IF (selectedTotal.innerHTML = 0! ) {
             Var CON = Confirm The ( 'OK to delete the selected merchandise it?'); // pop-up confirmation box 
            IF (CON) {
                 var = shoes_id '' ;
                 for ( var I = 0; I <tr.length; I ++ ) {
                     // if selected, delete the corresponding rows 
                    IF (TR [I] .getElementsByTagName ( 'INPUT') [0 ] .checked ) { 
                        shoes_id = shoes_id TR + [I] .Cells [0] + .innerHTML ',' ; 
                        
                        //tr [i] .parentNode.removeChild (tr [ i]); // delete the node 
                        // i--; // standard back-off location 
                    } 
                } 
                Alert (shoes_id); 
                window.location.href ? = "Method ShopServlet = & shoes_id deleteFromCart = "+ shoes_id +" & user_id = "+ 22 is ; 
                Alert ( " deleted successfully "! ); 
            } 
        } the else { 
            Alert ( 'Please select!' ); 
        } 
        getTotal (); // Number of update 
    }