Java @SentinelResource example code analysis

Limit flow by resource name and add subsequent processing

Module:cloudalibaba-sentinel-service8401

Pom new dependency

  <dependency><!-- 引入自己定义的api通用包，可以使用Payment支付Entity -->
            <groupId>com.atguigu.springcloud</groupId>
            <artifactId>cloud-api-common</artifactId>
            <version>${project.version}</version>
        </dependency>

This dependency comes from your own template, here This dependency is part of the business processing of database query

New Controller

@RestController
public class RateLimitController
{
    @GetMapping("/byResource")
    @SentinelResource(value = "byResource",blockHandler = "handleException")
    public CommonResult byResource()
    {
        return new CommonResult(200,"按资源名称限流测试OK",new Payment(2020L,"serial001"));
    }
    public CommonResult handleException(BlockException exception)
    {
        return new CommonResult(444,exception.getClass().getCanonicalName()+"\t 服务不可用");
    }
}

##Graphic configuration and code relationship

means that the number of queries within 1 second is greater than 1, then it will go to our custom flow and limit the flow

Test 1

Click 1 time in 1 second, OK

Exceeded the above, clicked like crazy, returned self-defined current limiting processing information, current limiting occurred

According to the Url address current limiting and subsequent processing

Limiting the current through the accessed URL will return the default current limiting processing information provided by Sentinel

Controller is modified to:

@RestController
public class RateLimitController
{
    @GetMapping("/byResource")
    @SentinelResource(value = "byResource",blockHandler = "handleException")
    public CommonResult byResource()
    {
        return new CommonResult(200,"按资源名称限流测试OK",new Payment(2020L,"serial001"));
    }
    public CommonResult handleException(BlockException exception)
    {
        return new CommonResult(444,exception.getClass().getCanonicalName()+"\t 服务不可用");
    }
    @GetMapping("/rateLimit/byUrl")
    @SentinelResource(value = "byUrl")
    public CommonResult byUrl()
    {
        return new CommonResult(200,"按url限流测试OK",new Payment(2020L,"serial002"));
    }
}

Test 2

Visit once

http://localhost:8401/rateLimit/byUrl

Normal

Crazy click http://localhost:8401/rateLimit/ byUrl

will return Sentinel’s own current limiting processing results

Problems faced by the above solution

1 The system defaults, no Reflect our own business requirements.

2 According to the existing conditions, our customized processing method is coupled with the business code, which is not intuitive.

3 If a caveat is added to each business method, the code bloat will increase.

4 The global unified processing method is not reflected.

Customer-defined current-limiting processing logic

Create the CustomerBlockHandler class for customizing current-limiting processing logic

After testing, we customized it

Add new business to the control class

  @GetMapping("/rateLimit/customerBlockHandler")
    @SentinelResource(value = "customerBlockHandler",
            blockHandlerClass = CustomerBlockHandler.class, blockHandler = "handleException2")
    public CommonResult customerBlockHandler()
    {
        return new CommonResult(200,"按客户自定义限流处理逻辑");
    }

Customize general current limiting processing logic

blockHandlerClass = CustomerBlockHandler.class

blockHandler = handleException2

The above configuration: Find the handleException2 method in the CustomerBlockHandler class for back-up processing and define general current limiting processing logic

Test 3

After testing, we customized it

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