springboot 接口幂等

落日映苍穹つ 2022-09-08 00:15 104阅读 0赞

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## springboot 接口幂等 ##

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**接口幂等**

**幂等：多次操作与一次操作，产生的结果相同**

**应用：解决表单重复提交造成的数据重复、超时重试引发的重复操作等问题**

**数据插入幂等**

对数据记录中的字段做唯一性限制（如订单号），将字段设为主键、或者添加唯一索引

**数据更新幂等**

#使用乐观锁
    update t set value=new_value and version=version+1 
    where value=#{value} and version=#{version}
    重复提交，由于version值已经改变，后续更新操作不会执行
    
    
    #业务自带状态标识（如订单status)，处理方式类似乐观锁 
    status => 0:已下单、1:已支付、2已发货、3:确认收货、4:退款中、5:已退款
    update order set status=3 where order_id=#{orderId} and status=2
    重复提交时，由于status已经改变，后续更新操作不会执行

**token 标识**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_Q1NETiBAb1_nk5znlLDmnY7kuItfbw_size_12_color_FFFFFF_t_70_g_se_x_16][]

**客户端获取token，****将token设置为下次请求的header**

**请求到达接口前先进行检验，****如果没有token、或者token不等，则直接返回**

**如果token检验通过，执行接口，并返回操作结果**

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**示例：token实现接口幂等**

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**annotation 层**

**   **

**Idempotent**

@Documented
    @Target(ElementType.METHOD)
    @Retention(RetentionPolicy.RUNTIME)
    public @interface Idempotent {
    }

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**util 层**

**StoreUtil**

public class StoreUtil {
    
        private static final Map<String,String> map=new HashMap<>();
    
        public static void putValue(String key, String value){
            map.put(key, value);
        }
    
        public static String getValue(String key){
            return map.get(key);
        }
    
        public static void removeValue(String key){
            map.remove(key);
        }
    }

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**service 层**

**IdempotentService**

@Service
    public class IdempotentService {
    
        public Map<String,String> createToken(){
            Map<String,String> result = new HashMap<>();
    
            String tokenName = RandomStringUtils.randomAlphanumeric(6);
            String tokenValue = RandomStringUtils.randomNumeric(10);
            result.put("tokenName",tokenName);
            result.put("tokenValue",tokenValue);
    
            StoreUtil.putValue(tokenName,tokenValue);
    
            return result;
        }
    
        public boolean checkToken(String tokenName, String tokenValue){
            if (tokenName==null || tokenValue==null){
                return false;
            }
    
            synchronized (this){
                if (tokenValue.equals(StoreUtil.getValue(tokenName))){
                    StoreUtil.removeValue(tokenName);
    
                    return true;
                }
            }
    
            return false;
        }
    }

**\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\***

**interceptor 层**

**CustomInterceptor**

@Component
    public class CustomInterceptor implements HandlerInterceptor {
    
        @Resource
        private IdempotentService idempotentService;
    
        @Override
        public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
            if (handler instanceof HandlerMethod){
                Method method = ((HandlerMethod) handler).getMethod();
    
                if (method.isAnnotationPresent(Idempotent.class)){
                    String tokenName = request.getHeader("tokenName");
                    String tokenValue = request.getHeader("tokenValue");
                    System.out.println(tokenName+"  "+tokenValue);
    
                    if (!idempotentService.checkToken(tokenName, tokenValue)){
                        JSONObject object=new JSONObject();
                        object.put("code","111111");
                        object.put("status","error");
                        object.put("msg","token 检验失败");
                        response.setContentType("application/json;charset=UTF-8");
                        response.getWriter().println(object);
    
                        return false;
                    }
                }
            }
    
            return true;
        }
    }

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**config 层**

**WebConfig**

@Configuration
    public class WebConfig implements WebMvcConfigurer {
    
        @Resource
        private CustomInterceptor customInterceptor;
    
        @Override
        public void addInterceptors(InterceptorRegistry registry) {
            registry.addInterceptor(customInterceptor);
        }
    
        @Override
        public void addViewControllers(ViewControllerRegistry registry) {
            registry.addViewController("/index").setViewName("index");
        }
    }

**\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\***

**controller 层**

**HelloController**

@RestController
    public class HelloController {
    
        @Resource
        private IdempotentService idempotentService;
    
        @RequestMapping("/token")
        public Map<String, String> getToken(){
            return idempotentService.createToken();
        }
    
        @Idempotent
        @RequestMapping("/hello")
        public Map<String,Object> hello(String name, Integer age){
            System.out.println(name+"  "+age);
    
            Map<String,Object> result = new HashMap<>();
            result.put("code","000000");
            result.put("status","success");
    
            return result;
        }
    }

**\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\***

**前端页面**

**index.html**

<!DOCTYPE html>
    <html lang="en" xmlns="http://www.w3.org/1999/xhtml"
          xmlns:th="http://www.thymeleaf.org" xmlns:sec="http://www.thymeleaf.org/thymeleaf-extras-springsecurity5">
    <head>
        <meta charset="UTF-8">
        <title>$Title$</title>
        <script src="/jquery/jquery-3.6.0.min.js"></script>
        <script src="/layui-v2.6.8/layui/layui.js"></script>
        <link rel="stylesheet" href="/layui-v2.6.8/layui/css/layui.css">
        <script>
            $(function (){
                let tokenName, tokenValue;
    
                $.get({
                    url: "/token",
                    success: function (result){
                        tokenName = result.tokenName;
                        tokenValue = result.tokenValue;
                        layer.msg(tokenName+"  "+tokenValue);
    
                        $("#btn").click(function (){
                            $.ajax({
                                type: "get",
                                url: "/hello",
                                headers: {
                                    tokenName: tokenName,
                                    tokenValue: tokenValue
                                },
                                data: {
                                    name: $("#name").val(),
                                    age: $("#age").val()
                                },
                                success: function (result){
                                    layer.msg(result.status.toString())
                                }
                            })
                        })
                    }
                })
            })
        </script>
    </head>
    <body>
        <div th:align="center">
            <div class="layui-form-item">
                <label class="layui-form-label">name</label>
                <div class="layui-input-block">
                    <input type="text" id="name" required  lay-verify="required" placeholder="请输入name" autocomplete="off" class="layui-input">
                </div>
            </div>
            <div class="layui-form-item">
                <label class="layui-form-label">age</label>
                <div class="layui-input-inline">
                    <input type="text" id="age" required lay-verify="required" placeholder="请输入age" autocomplete="off" class="layui-input">
                </div>
            </div>
            <div class="layui-form-item">
                <div class="layui-input-block">
                    <button id="btn" class="layui-btn">提交</button>
                </div>
            </div>
        </div>
    </body>
    </html>

## \*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\* ##

**使用测试**

**localhost:8080/index**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_Q1NETiBAb1_nk5znlLDmnY7kuItfbw_size_15_color_FFFFFF_t_70_g_se_x_16][]

**控制台输出**

2021-08-25 20:20:40.608  INFO 12508 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : Completed initialization in 1 ms
    2021-08-25 20:20:42.082  WARN 12508 --- [nio-8080-exec-9] o.a.c.util.SessionIdGeneratorBase        : Creation of SecureRandom instance for session ID generation using [SHA1PRNG] took [126] milliseconds.
    jkjBTq  4624310419
    瓜田李下  20

## \*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\* ##

**jmeter 测试**

**获取token**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_Q1NETiBAb1_nk5znlLDmnY7kuItfbw_size_12_color_FFFFFF_t_70_g_se_x_16 1][]

**添加线程组**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_Q1NETiBAb1_nk5znlLDmnY7kuItfbw_size_12_color_FFFFFF_t_70_g_se_x_16 2][]

**线程组下添加** **HTTP Request**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_Q1NETiBAb1_nk5znlLDmnY7kuItfbw_size_15_color_FFFFFF_t_70_g_se_x_16 1][]

**添加****HTTP Header Manager：****设置请求头**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_Q1NETiBAb1_nk5znlLDmnY7kuItfbw_size_15_color_FFFFFF_t_70_g_se_x_16 2][]

**添加 View Reqults Tree：查看请求结果**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_Q1NETiBAb1_nk5znlLDmnY7kuItfbw_size_15_color_FFFFFF_t_70_g_se_x_16 3][]

**点击运行，查看请求结果**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_Q1NETiBAb1_nk5znlLDmnY7kuItfbw_size_15_color_FFFFFF_t_70_g_se_x_16 4][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_Q1NETiBAb1_nk5znlLDmnY7kuItfbw_size_15_color_FFFFFF_t_70_g_se_x_16 5][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_Q1NETiBAb1_nk5znlLDmnY7kuItfbw_size_15_color_FFFFFF_t_70_g_se_x_16 6][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_Q1NETiBAb1_nk5znlLDmnY7kuItfbw_size_15_color_FFFFFF_t_70_g_se_x_16 7][]

**四次请求，只有一次请求执行成功**

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