详解Spring Boot使用redis实现数据缓存

基于spring boot 1.5.2.release版本，一方面验证与redis的集成方法，另外了解使用方法。

集成方法

1、配置依赖

修改pom.xml，增加如下内容。

  <dependency> 
    <groupid>org.springframework.boot</groupid> 
    <artifactid>spring-boot-starter-data-redis</artifactid> 
  </dependency> 

2、配置redis

修改application.yml，增加如下内容。

spring:
  redis:
    host: localhost 
    port: 6379
    pool:
      max-idle: 8 
      min-idle: 0
      max-active: 8
      max-wait: -1

3、配置redis缓存

package net.jackieathome.cache;

import java.lang.reflect.method;

import org.springframework.cache.cachemanager;
import org.springframework.cache.annotation.cachingconfigurersupport;
import org.springframework.cache.annotation.enablecaching;
import org.springframework.cache.interceptor.keygenerator;
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;
import org.springframework.data.redis.core.stringredistemplate;
import org.springframework.data.redis.serializer.jackson2jsonredisserializer;

import com.fasterxml.jackson.annotation.jsonautodetect;
import com.fasterxml.jackson.annotation.propertyaccessor;
import com.fasterxml.jackson.databind.objectmapper;

@configuration
@enablecaching // 启用缓存特性
public class redisconfig extends cachingconfigurersupport {
  // 缓存数据时key的生成器，可以依据业务和技术场景自行定制
// @bean
// public keygenerator customizedkeygenerator() {
//   return new keygenerator() {
//     @override
//     public object generate(object target, method method, object... params) {
//       stringbuilder sb = new stringbuilder();
//       sb.append(target.getclass().getname());
//       sb.append(method.getname());
//       for (object obj : params) {
//         sb.append(obj.tostring());
//       }
//       return sb.tostring();
//     }
//   };
//
// }
  // 定制缓存管理器的属性，默认提供的cachemanager对象可能不能满足需要
  // 因此建议依赖业务和技术上的需求，自行做一些扩展和定制
  @bean
  public cachemanager cachemanager(@suppresswarnings("rawtypes") redistemplate redistemplate) {
    rediscachemanager rediscachemanager = new rediscachemanager(redistemplate);
    rediscachemanager.setdefaultexpiration(300);
    return rediscachemanager;
  }

  @bean
  public redistemplate<string, string> redistemplate(redisconnectionfactory factory) {
    stringredistemplate template = new stringredistemplate(factory);
    jackson2jsonredisserializer jackson2jsonredisserializer = new jackson2jsonredisserializer(object.class);
    objectmapper om = new objectmapper();
    om.setvisibility(propertyaccessor.all, jsonautodetect.visibility.any);
    om.enabledefaulttyping(objectmapper.defaulttyping.non_final);
    jackson2jsonredisserializer.setobjectmapper(om);
    template.setvalueserializer(jackson2jsonredisserializer);
    template.afterpropertiesset();
    return template;
  }
}

验证集成后的效果

考虑到未来参与的项目基于mybatis实现数据库访问，而利用缓存，可有效改善web页面的交互体验，因此设计了如下两个验证方案。

方案一

在访问数据库的数据对象上增加缓存注解，定义缓存策略。从测试效果看，缓存有效。

1、页面控制器

package net.jackieathome.controller;

import java.util.list;

import org.springframework.beans.factory.annotation.autowired;
import org.springframework.web.bind.annotation.pathvariable;
import org.springframework.web.bind.annotation.requestmapping;
import org.springframework.web.bind.annotation.requestmethod;
import org.springframework.web.bind.annotation.restcontroller;

import net.jackieathome.bean.user;
import net.jackieathome.dao.userdao;
import net.jackieathome.db.mapper.usermapper;

@restcontroller
public class usercontroller {

  @autowired
  private userdao userdao;

  @requestmapping(method = requestmethod.get, value = "/user/id/{id}")
  public user finduserbyid(@pathvariable("id") string id) {
    return userdao.finduserbyid(id);
  }

  @requestmapping(method = requestmethod.get, value = "/user/create")
  public user createuser() {
    long time = system.currenttimemillis() / 1000;

    string id = "id" + time;
    user user = new user();
    user.setid(id);
    userdao.createuser(user);

    return userdao.finduserbyid(id);
  }
}

2、mapper定义

package net.jackieathome.db.mapper;

import java.util.list;

import org.apache.ibatis.annotations.mapper;
import org.apache.ibatis.annotations.param;
import org.springframework.cache.annotation.cacheconfig;
import org.springframework.cache.annotation.cacheput;
import org.springframework.cache.annotation.cacheable;

import net.jackieathome.bean.user;


@mapper
public interface usermapper {

  void createuser(user user);

  user finduserbyid(@param("id") string id);
}

3、数据访问对象

package net.jackieathome.dao;

import java.util.arraylist;
import java.util.list;

import org.apache.ibatis.annotations.param;
import org.slf4j.logger;
import org.slf4j.loggerfactory;
import org.springframework.beans.factory.annotation.autowired;
import org.springframework.cache.annotation.cacheconfig;
import org.springframework.cache.annotation.cacheput;
import org.springframework.cache.annotation.cacheable;
import org.springframework.stereotype.component;
import org.springframework.transaction.annotation.transactional;

import net.jackieathome.bean.user;
import net.jackieathome.db.mapper.usermapper;

@component
@cacheconfig(cachenames = "users")
@transactional
public class userdao {
  private static final logger log = loggerfactory.getlogger(userdao.class);
  @autowired
  private usermapper usermapper;

  @cacheput(key = "#p0.id")
  public void createuser(user user) {
    usermapper.createuser(user);
    log.debug("create user=" + user);
  }

  @cacheable(key = "#p0")
  public user finduserbyid(@param("id") string id) {
    log.debug("find user=" + id);
    return usermapper.finduserbyid(id);
  }
}

方案二

直接在mapper定义上增加缓存注解，控制缓存策略。从测试效果看，缓存有效，相比于方案一，测试代码更加简洁一些。

1、页面控制器

package net.jackieathome.controller;

import java.util.list;

import org.springframework.beans.factory.annotation.autowired;
import org.springframework.web.bind.annotation.pathvariable;
import org.springframework.web.bind.annotation.requestmapping;
import org.springframework.web.bind.annotation.requestmethod;
import org.springframework.web.bind.annotation.restcontroller;

import net.jackieathome.bean.user;
import net.jackieathome.dao.userdao;
import net.jackieathome.db.mapper.usermapper;

@restcontroller
public class usercontroller {

  @autowired
  private usermapper usermapper;

  @requestmapping(method = requestmethod.get, value = "/user/id/{id}")
  public user finduserbyid(@pathvariable("id") string id) {
    return usermapper.finduserbyid(id);
  }

  @requestmapping(method = requestmethod.get, value = "/user/create")
  public user createuser() {
    long time = system.currenttimemillis() / 1000;

    string id = "id" + time;
    user user = new user();
    user.setid(id);
    usermapper.createuser(user);

    return usermapper.finduserbyid(id);
  }
}

2、mapper定义

package net.jackieathome.db.mapper;

import java.util.list;

import org.apache.ibatis.annotations.mapper;
import org.apache.ibatis.annotations.param;
import org.springframework.cache.annotation.cacheconfig;
import org.springframework.cache.annotation.cacheput;
import org.springframework.cache.annotation.cacheable;

import net.jackieathome.bean.user;

@cacheconfig(cachenames = "users")
@mapper
public interface usermapper {

  @cacheput(key = "#p0.id")
  void createuser(user user);

  @cacheable(key = "#p0")
  user finduserbyid(@param("id") string id);
}

总结

上述两个测试方案并没有优劣之分，仅是为了验证缓存的使用方法，体现了不同的控制粒度，在实际的项目开发过程中，需要依据实际情况做不同的决断。

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