[二十三]SpringBoot 之 redis

 

本文章牵涉到的技术点比较多：spring Data JPA、Redis、Spring MVC,Spirng Cache，所以在看这篇文章的时候，需要对以上这些技术点有一定的了解或者也可以先看看这篇文章，针对文章中实际的技术点在进一步了解（注意，您需要自己下载Redis Server到您的本地，所以确保您本地的Redis可用，这里还使用了MySQL数据库，当然你也可以内存数据库进行测试）。这篇文章会提供对应的Eclipse代码示例，具体大体的分如下几个步骤：

（1）新建Java MavenProject;

（2）在pom.xml中添加相应的依赖包；

（3）编写Spring Boot启动类；

（4）配置application.properties;

（5）编写RedisCacheConfig配置类；

（6）编写DemoInfo测试实体类；

（7）编写DemoInfoRepository持久化类；

（8）编写DemoInfoService类；

（9）编写DemoInfoController类；

（10）测试代码是否正常运行了

（11）自定义缓存key;

（1）新建Java Maven Project;

（2）在pom.xml中添加相应的依赖包；

<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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>me.shijunjie</groupId>
    <artifactId>testspringbootredis</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>testspringbootredis</name>
    <url>http://maven.apache.org</url>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.3.3.RELEASE</version>
    </parent>

    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <scope>test</scope>
        </dependency>
        <!-- springboot web支持：mvc,aop... -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context-support</artifactId>
        </dependency>

        <!-- 添加redis支持 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-redis</artifactId>
        </dependency>

        <!-- JPA操作数据库. -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>

        <!-- mysql数据库驱动. -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>

        <!-- https://mvnrepository.com/artifact/commons-pool/commons-pool -->
        <!-- <dependency>
            <groupId>commons-pool</groupId>
            <artifactId>commons-pool</artifactId>
        </dependency> -->

        <!-- https://mvnrepository.com/artifact/org.apache.commons/commons-pool2 -->
        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-pool2</artifactId>
        </dependency>

        <!-- 单元测试. -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin </artifactId>
            </plugin>

            <!-- <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin 
                </artifactId> <dependencies> springloaded hotdeploy <dependency> <groupId>org.springframework</groupId> 
                <artifactId>springloaded</artifactId> <version>1.2.4.RELEASE</version> </dependency> 
                </dependencies> <executions> <execution> <goals> <goal>repackage</goal> </goals> 
                <configuration> <classifier>exec</classifier> </configuration> </execution> 
                </executions> </plugin> -->

            <!-- java编译插件 -->
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                    <encoding>UTF-8</encoding>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

（3）编写Spring Boot启动类（com.kfit.App）；

package me.shijunjie.testspringbootredis;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.orm.jpa.EntityScan;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;

@SpringBootApplication
@ComponentScan("me.shijunjie")
@EnableJpaRepositories("me.shijunjie.repository")
@EntityScan("me.shijunjie.bean")
public class App 
{
    public static void main( String[] args )
    {
        SpringApplication.run(App.class, args);
    }
}

（4）配置application.properties;

########################################################

###datasource \u914D\u7F6EMySQL\u6570\u636E\u6E90\uFF1B

########################################################

spring.datasource.url =jdbc:mysql://123.206.228.200:3306/test

spring.datasource.username = shijunjie

spring.datasource.password = ******

spring.datasource.driverClassName =com.mysql.jdbc.Driver

spring.datasource.max-active=20

spring.datasource.max-idle=8

spring.datasource.min-idle=8

spring.datasource.initial-size=10

########################################################

###REDIS (RedisProperties) redis\u57FA\u672C\u914D\u7F6E\uFF1B

########################################################

# database name

spring.redis.database=0

# server host1

spring.redis.host=123.206.228.200

# server password

spring.redis.password=******

#connection port

spring.redis.port=6379

# pool settings ...

spring.redis.pool.max-idle=8

spring.redis.pool.min-idle=0

spring.redis.pool.max-active=8

spring.redis.pool.max-wait=-1

# name of Redis server

#spring.redis.sentinel.master=

# comma-separated list of host:portpairs

#spring.redis.sentinel.nodes=

########################################################

### Java Persistence Api \u81EA\u52A8\u8FDB\u884C\u5EFA\u8868

########################################################

# Specify the DBMS

spring.jpa.database = MYSQL

# Show or not log for each sqlquery

spring.jpa.show-sql = true

# hibernate ddl auto (create,create-drop, update)

spring.jpa.hibernate.ddl-auto = update

# Naming strategy

spring.jpa.hibernate.naming-strategy =org.hibernate.cfg.ImprovedNamingStrategy

# stripped before adding them tothe entity manager)

spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.MySQL5Dialect

（5）编写RedisCacheConfig配置类；

缓存主要有几个要实现的类：其一就是CacheManager缓存管理器；其二就是具体操作实现类；其三就是CacheManager工厂类（这个可以使用配置文件配置的进行注入，也可以通过编码的方式进行实现）；其四就是缓存key生产策略（当然Spring自带生成策略，但是在Redis客户端进行查看的话是系列化的key,对于我们肉眼来说就是感觉是乱码了，这里我们先使用自带的缓存策略）。

package me.shijunjie.config;

import org.springframework.cache.CacheManager;
import org.springframework.cache.annotation.CachingConfigurerSupport;
import org.springframework.cache.annotation.EnableCaching;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.cache.RedisCacheManager;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.data.redis.core.RedisTemplate;

@Configuration
@EnableCaching //启用缓存，这个注解很重要；
public class RedisCacheConfig extends CachingConfigurerSupport {
     /**
     * 缓存管理器.
     * @param redisTemplate
     * @return
     */
    @Bean
    public CacheManager cacheManager(RedisTemplate<?,?> redisTemplate) {
           CacheManager cacheManager = new RedisCacheManager(redisTemplate);
           return cacheManager;
    }
    
    /**
     * redis模板操作类,类似于jdbcTemplate的一个类;
     * 虽然CacheManager也能获取到Cache对象，但是操作起来没有那么灵活；
     * 这里在扩展下：RedisTemplate这个类不见得很好操作，我们可以在进行扩展一个我们
     * 自己的缓存类，比如：RedisStorage类;
     * @param factory : 通过Spring进行注入，参数在application.properties进行配置；
     * @return
     */
    @Bean
    public RedisTemplate<String, String> redisTemplate(RedisConnectionFactory factory) {
           RedisTemplate<String,String> redisTemplate = new RedisTemplate<String, String>();
           redisTemplate.setConnectionFactory(factory);
           //key序列化方式;（不然会出现乱码;）,但是如果方法上有Long等非String类型的话，会报类型转换错误；
           //所以在没有自己定义key生成策略的时候，以下这个代码建议不要这么写，可以不配置或者自己实现ObjectRedisSerializer
           //或者JdkSerializationRedisSerializer序列化方式;
//        RedisSerializer<String>redisSerializer = new StringRedisSerializer();//Long类型不可以会出现异常信息;
//        redisTemplate.setKeySerializer(redisSerializer);
//        redisTemplate.setHashKeySerializer(redisSerializer);
           return redisTemplate;
    }
}

（6）编写DemoInfo测试实体类；

package me.shijunjie.bean;

import java.io.Serializable;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;

@Entity
public class DemoInfo  implements Serializable{
    private static final long serialVersionUID = 1L;

    @Id @GeneratedValue
    private long id;
    private String name;
    private String pwd;
    public long getId() {
        return id;
    }
    public void setId(long id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getPwd() {
        return pwd;
    }
    public void setPwd(String pwd) {
        this.pwd = pwd;
    }
    @Override
    public String toString() {
        return "DemoInfo [id=" + id + ", name=" + name + ", pwd=" + pwd + "]";
    }

}

（7）编写DemoInfoRepository持久化类；

package me.shijunjie.repository;

import java.io.Serializable;

import org.springframework.data.repository.CrudRepository;
import org.springframework.stereotype.Repository;

import me.shijunjie.bean.DemoInfo;

@Repository
public interface DemoInfoRepository extends CrudRepository<DemoInfo, Serializable> {

}

（8）编写DemoInfoService类；

       编写DemoInfoService，这里有两个技术方面，第一就是使用Spring @Cacheable注解方式和RedisTemplate对象进行操作，具体代码如下：

package me.shijunjie.service;

import me.shijunjie.bean.DemoInfo;

public interface DemoInfoService {
     public DemoInfo findById(long id);
     public void deleteFromCache(long id);
     void test();
     void save(DemoInfo demoInfo);
}

package me.shijunjie.service.impl;

import javax.annotation.Resource;

import org.springframework.cache.annotation.CacheEvict;
import org.springframework.cache.annotation.Cacheable;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.core.ValueOperations;
import org.springframework.stereotype.Service;

import me.shijunjie.bean.DemoInfo;
import me.shijunjie.repository.DemoInfoRepository;
import me.shijunjie.service.DemoInfoService;

@Service
public class DemoInfoServiceImpl implements DemoInfoService {
    
    @Resource
    private DemoInfoRepository demoInfoDao;
    
    @Resource
    private RedisTemplate<String,String> redisTemplate;

    @Cacheable(value="demoInfo") //缓存,这里没有指定key.
    @Override
    public DemoInfo findById(long id) {
        System.err.println("DemoInfoServiceImpl.findById()=========从数据库中进行获取的....id="+id);
        DemoInfo demoInfo = demoInfoDao.findOne(id);
        return demoInfo;
    }

    @CacheEvict(value="demoInfo")
    @Override
    public void deleteFromCache(long id) {
        System.out.println("DemoInfoServiceImpl.delete().从缓存中删除.");
    }

    @Override
    public void test() {
         ValueOperations<String,String> valueOperations = redisTemplate.opsForValue();
         valueOperations.set("mykey4", "random1="+Math.random());
         System.out.println(valueOperations.get("mykey4"));
    }

    @Override
    public void save(DemoInfo demoInfo) {
        demoInfoDao.save(demoInfo);
    }

}

（9）编写DemoInfoController类；

package me.shijunjie.controller;

import javax.annotation.Resource;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

import me.shijunjie.bean.DemoInfo;
import me.shijunjie.service.DemoInfoService;

@Controller
public class DemoInfoController {
    @Resource
    DemoInfoService demoInfoService;

    @RequestMapping("/save")
    public @ResponseBody String save(){
        DemoInfo demoInfo = new DemoInfo();
        demoInfo.setName("aaa");
        demoInfo.setPwd("aaab");
        demoInfoService.save(demoInfo);
        return "ok";
    }
    
    @RequestMapping("/test")
    public @ResponseBody String test(){
        DemoInfo loaded = demoInfoService.findById(1);
        System.out.println("loaded="+loaded);
        DemoInfo cached = demoInfoService.findById(1);
        System.out.println("cached="+cached);
        loaded = demoInfoService.findById(2);
        System.out.println("loaded2="+loaded);
        return "ok";
    }

    @RequestMapping("/delete")
    public @ResponseBody String delete(long id){
        demoInfoService.deleteFromCache(id);
        return "ok";
    }

    @RequestMapping("/test1")
    public @ResponseBody String test1(){
        demoInfoService.test();
        System.out.println("DemoInfoController.test1()");
        return "ok";
    }
}

（10）测试代码是否正常运行了

启动应用程序，访问地址：http://127.0.0.1:8080/test

查看控制台可以查看：

（11）自定义缓存key;

在me.shijunjie.config.RedisCacheConfig类中重写CachingConfigurerSupport中的keyGenerator ,具体实现代码如下：

/**
     * 自定义key.
     * 此方法将会根据类名+方法名+所有参数的值生成唯一的一个key,即使@Cacheable中的value属性一样，key也会不一样。
     */
    @Override
    public KeyGenerator keyGenerator() {
        System.out.println("RedisCacheConfig.keyGenerator()");
        return new KeyGenerator() {
            
            @Override
            public Object generate(Object o, Method method, Object... args) {
                 StringBuilder sb = new StringBuilder();
                 sb.append(o.getClass().getName());
                 sb.append(method.getName());
                 for (Object obj : args) {
                        sb.append(obj.toString());
                 }
                 System.out.println("keyGenerator=" + sb.toString());
                 return sb.toString();
            }
        };
    }

具体参照http://blog.csdn.net/linxingliang/article/details/52263763