Lock4j -- distributed locking Middleware -- use / instance

Original website ：lock4j-- Distributed lock middleware -- Use / example _IT A blog with a sharp blade -CSDN Blog

brief introduction

explain

         This article introduces the distributed locking middleware with examples lock4j Usage of .

Related website

gitee：https://gitee.com/baomidou/lock4j

lock4j Reference items for ：https://gitee.com/kekingcn/spring-boot-klock-starter

summary

1. lock4j And @Transactional similar ： Write comments on Methods , Automatically control the lock and release lock .
2. lock4j Support Redis（RedisTemplate or Redisson）、Zookeeper As the bottom layer
   1. 2.0 Later support Redisson and Zookeeper
   2. Recommendations based on Redisson
      1. reason ： You can use redisson Characteristics of ： Automatic renewal, etc
      2. Method ： Introduce dependencies ：lock4j-redisson-spring-boot-starter
3. Support SPEL
4. Execution order
   1. If in service There are @Transactional and @lock4j, The execution sequence is as follows
      1. locked
      2. Open transaction
      3. Perform logical
      4. Submit / Roll back the transaction
      5. Release the lock
5. Realization principle
   1. AOP：Advisor + methodInterception

example

        This article takes Redisson Use... For the bottom layer lock4j.

rely on

<dependency>
	<groupId>com.baomidou</groupId>
	<artifactId>lock4j-redisson-spring-boot-starter</artifactId>
	<version>2.2.2</version>
</dependency>

Whole pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.4.13</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.knife.demo</groupId>
    <artifactId>demo_lock4j_SpringBoot</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>demo_lock4j_SpringBoot</name>
    <description>demo_lock4j_SpringBoot</description>
    <properties>
        <java.version>1.8</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <!-- https://mvnrepository.com/artifact/com.baomidou/lock4j-redisson-spring-boot-starter -->
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>lock4j-redisson-spring-boot-starter</artifactId>
            <version>2.2.2</version>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>

        <dependency>
            <groupId>com.github.xiaoymin</groupId>
            <artifactId>knife4j-spring-boot-starter</artifactId>
            <version>3.0.3</version>
        </dependency>

    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <excludes>
                        <exclude>
                            <groupId>org.projectlombok</groupId>
                            <artifactId>lombok</artifactId>
                        </exclude>
                    </excludes>
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>

To configure

application.yml

spring:
  redis:
    host: 192.168.5.193
    port: 6379
    password: 222333

#lock4j:
#  acquire-timeout: 3000 # The default value is 3s, Not set up 
#  expire: 30000 # The default value is 30s, Not set up 
#  primary-executor: com.baomidou.lock.executor.RedissonLockExecutor # Default redisson > redisTemplate > zookeeper, Not set up 
#  lock-key-prefix: lock4j # lock key Prefix ,  The default value is lock4j, Not set up 

Code

Controller

This office will directly @Lock4j writes Controller On the way , It should be written in the actual development Service On the method of the implementation class .

package com.knife.demo.controller;

import com.baomidou.lock.annotation.Lock4j;
import com.knife.demo.entity.User;
import io.swagger.annotations.Api;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.List;

@Api(tags = " user ")
@RestController
@RequestMapping("user")
public class UserController {
    @GetMapping("listAll")
    @Lock4j
    public List<User> listAllUser() {
        return null;
    }

    @GetMapping("find")
    @Lock4j(keys = {"#user.id", "#user.name"}, expire = 60000, acquireTimeout = 1000)
    public List<User> find(User user) {
        return null;
    }
}

Entity

package com.knife.demo.entity;

import lombok.Data;

@Data
public class User {
    private Long id;

    private String name;
}

test

Visit the test page ：http://localhost:8080/doc.html

test 1： No parameter 、 No options

Pre operational Redis：（ No data ）

Breaking point

Access interface

Enter the breakpoint

see Redis Information （ Write data ）

Let go of the breakpoint , Method execution ends （Redis Data is deleted ）

test 2： With parameters 、 With options

  Pre operational Redis：（ No data ）

Breaking point

Access interface （id The assignment is ：123,name The assignment is ：Tony）

Enter the breakpoint

see Redis Information （ Write data ）

Let go of the breakpoint , Method execution ends （Redis Data is deleted ）