更新购物车商品数量
用户点击商品数量加减按钮，向后端发送请求，更新购物车数据表
持久层
规划执行的SQL语句
本质是更新语句，更具cid跟新num字段值，在前面功能模块中已经实现
在执行更新操作之前，还需要判断当前购物车记录在数据库表中是否存在，本质是查询语句
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| select * from t_cart where cid=?;
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接口和抽象方法
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Cart findByCid(Integer cid);
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SQL映射文件配置
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| <select id="findByCid" resultMap="cartPojoMap">
select * from t_cart where cid=#{cid};
</select>
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单元测试
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| @Test
public void findByCid(){
Cart cart = cartMapper.findByCid(1);
System.out.println(cart);
}
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业务层
规划异常
1.数据更新过程中会发生异常，此异常类在此前的功能模块中已经定义
2.查询数据与登录用户不匹配引发的异常，此异常在此前功能模块中也已经定义
3.查询的购物车记录在数据库中不存在，创建对应的异常类CartNotFoundException
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| package com.bang.store.service.ex;
public class CartNotFoundException extends ServiceException{
public CartNotFoundException() {
super();
}
public CartNotFoundException(String message) {
super(message);
}
public CartNotFoundException(String message, Throwable cause) {
super(message, cause);
}
public CartNotFoundException(Throwable cause) {
super(cause);
}
protected CartNotFoundException(String message, Throwable cause, boolean enableSuppression, boolean writableStackTrace) {
super(message, cause, enableSuppression, writableStackTrace);
}
}
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接口和抽象方法
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Integer alterNum(Integer cid,Integer uid,String username,Integer changeNum);
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抽象方法实现
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| @Override
public Integer alterNum(Integer cid, Integer uid, String username, Integer changeNum) {
Cart result = cartMapper.findByCid(cid);
if(result==null){
throw new CartNotFoundException("数据库该数据不存在");
}
if(!result.getUid().equals(uid)){
throw new AccessDeniedException("非法数据访问");
}
Integer rows = cartMapper.updateNumByCid(cid, result.getNum() + changeNum, username, new Date());
if(rows!=1){
throw new UpdateException("数据更新过程发生未知错误");
}
return result.getNum()+changeNum;
}
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单元测试
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| @Test
public void alertNum(){
Integer num = cartService.alterNum(1, 1, "admin", -20);
System.out.println(num);
}
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控制层
处理异常
在控制层基类BaseController中添加购物车数据不存在异常CartNotFoundException
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| else if (e instanceof CartNotFoundException) {
result.setState(9000);
result.setMessage("购物车数据不存在");
}
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设计请求
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| request url: /cart/alter_num/{cid}/{opcode} //restful数据访问,cid代表购物车数据id,opcode:1代表增加商品数量，0代表较小商品数量
request method: GET
request params: Integer cid,Integr opcode,HttpSession session
response data: new JsonResult<Integer>
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处理请求
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| @RequestMapping("/alter_num/{cid}/{opcode}")
public JsonResult<Integer> alterNum(@PathVariable Integer cid,@PathVariable Integer opcode,HttpSession session){
Integer uid = getUidFromSession(session);
String username = getUsernameFromSession(session);
Integer num = -1;
if(opcode==0){
num = cartService.alterNum(cid,uid,username,-1);
} else if (opcode==1) {
num = cartService.alterNum(cid,uid,username,1);
}
return new JsonResult<>(OK,"商品数量改变成功",num);
}
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前端页面
在cart.html页面点击增加或者减少按钮，改变购物车中对应商品的数量
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| function showCartList(){
$.ajax({
url: "/cart/"
,type: "GET"
,success: function (data){
if(data.state == 200){
alert("购物车数据获取成功");
$("#cart-list").empty();
cartList = data.data;
for(let i=0;i<cartList.length;i++){
htmlContent = "<tr>\n" +
"<td>\n" +
"<input name=\"cids\" value='#{cid}' type=\"checkbox\" class=\"ckitem\" />\n" +
"</td>\n" +
"<td><img src=\"..#{image}collect.png\" class=\"img-responsive\" /></td>\n" +
"<td>#{title}</td>\n" +
"<td>¥<span id=\"goodsPrice#{cid}\">#{price}</span></td>\n" +
"<td>\n" +
'<input id=\"price-#{cid}\" type=\"button\" value=\"-\" class=\"num-btn\" onclick="chageNum(#{cid},0)"/>\n' +
"<input id=\"goodsCount#{cid}\" type=\"text\" size=\"2\" readonly=\"readonly\" class=\"num-text\" value=\"#{num}\">\n" +
"<input id=\"price+#{cid}\" class=\"num-btn\" type=\"button\" value=\"+\" onclick=\"chageNum(#{cid},1)\"/>\n" +
"</td>\n" +
"<td><span id=\"goodsCast#{cid}\">#{totalPrice}</span></td>\n" +
"<td>\n" +
"<input type=\"button\" class=\"cart-del btn btn-default btn-xs\" value=\"删除\" />\n" +
"</td>\n" +
"</tr>";
htmlContent = htmlContent.replaceAll("#{cid}",cartList[i].cid);
htmlContent = htmlContent.replace("#{image}",cartList[i].productImage);
htmlContent = htmlContent.replace("#{title}",cartList[i].productTitle+(cartList[i].cartPrice-cartList[i].productPrice));
htmlContent = htmlContent.replace("#{num}",cartList[i].cartNum);
htmlContent = htmlContent.replace("#{price}",cartList[i].cartPrice);
htmlContent = htmlContent.replace("#{totalPrice}",cartList[i].cartNum*cartList[i].cartPrice);
$("#cart-list").append(htmlContent);
}
}else{
alert("购物车获取数据失败 "+data.message);
}
}
,error:function (xmh){
alert("购物车获取数据发生未知异常"+xmh.status);
}
});
}
function chageNum(cid,opcode){
$.ajax({
url: "/cart/alter_num/"+cid+"/"+opcode
,type: "GET"
,dataType: "JSON"
,success: function (data){
if(data.state == 200){
$("#goodsCount"+cid).val(data.data);
let price = $("#goodsPrice"+cid).html();
let totalPrice = price*data.data;
$("#goodsCast"+cid).html(totalPrice);
alert("购物车商品数量修改成功");
}else{
alert("购物车商品数量修改失败 "+data.message);
}
}
,error:function (xmh){
alert("购物车商品数量修改发生未知异常"+xmh.status);
}
});
}
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