使用Redis进行简单的数据缓存

引入spring-data-redis包、jedis、connection-pool包

applicationContext.xml的配置

    <!-- redis Connection -->
    <bean id="redisConnection" class="org.springframework.data.redis.connection.jedis.JedisConnectionFactory">
    <property name="hostName" value="localhost"></property>
    <property name="port" value="6379"></property>
    </bean>
    <!-- redisTemplate -->
    <bean id="redisTemplate" class="org.springframework.data.redis.core.RedisTemplate">
    <property name="connectionFactory" ref="redisConnection"></property>
    </bean>

做一个简单的测试

@Test
    public void test1() {
        Jedis jd = new Jedis("localhost",6379);
        String ping = jd.ping();
        System.out.println(ping);
        Set<String> keys = jd.keys("*");
        for(String k:keys){
            System.out.println(k + ":"+ jd.type(k));
        }
        jd.close();
      
    }
    
    @Test
    public void test2(){
        Jedis j=new Jedis("localhost", 6379);
        System.out.println(j.ping());
        Set<String>  filed=  j.hkeys("dept");
        System.out.println(filed);
        for(String s:filed){
            System.out.println(j.hget("dept", s));
        }
        j.close();
    }

自己写一个工具类将,进行序列化与反序列化,

public class SerializableUtil {

    public static byte[] objectToBytes(Object obj) {// 将对象转换为byte数组
        ByteArrayOutputStream baos = null;
        ObjectOutputStream oos = null;
        try {
            baos = new ByteArrayOutputStream();
            oos = new ObjectOutputStream(baos);
            oos.writeObject(obj);// 将数据序列化后写入到baos中
            byte[] byte1 = baos.toByteArray();
            return byte1;
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
            return null;
        } finally {
            try {
                baos.close();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            try {
                oos.close();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }

    }

    public static Object byteToObject(byte[] bytes) {
        ByteArrayInputStream bais = null;
        ObjectInputStream ois = null;
        try {
            bais = new ByteArrayInputStream(bytes);
            ois = new ObjectInputStream(bais);
            Object obj = ois.readObject();
            return obj;

        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
            return null;
        } finally {

            try {
                bais.close();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            try {
                ois.close();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

        }

    }

测试:

@Test
    public void test4(){
        
        DeptBean bean=new DeptBean(124, "zhangsan1", "shanghai");
        Jedis j=new Jedis("localhost", 6379);
        j.set("dept".getBytes(), SerializableUtil.objectToBytes(bean));
        j.close();
    }
    
    @Test
    public void test5(){
        Jedis j=new Jedis("localhost", 6379);
        byte[] bean=j.get("dept".getBytes());//获取到的是byte数组
        //在将byte数组反序列化
        DeptBean byteToObject = (DeptBean) SerializableUtil.byteToObject(bean);
        System.out.println(byteToObject);
        j.close();
    }

上面只是简单的使用自己写的一个工具类进行序列化与反序列化,实际开发中还是使用工具进行的,

写一个控制器,对其进行单元测试

@RunWith(SpringJUnit4ClassRunner.class)//这里的意思是进行一个spring环境的配置
@ContextConfiguration(locations = "classpath:applicationContext.xml")//让其能不启动tomcat服务器的情况下进行测试
public class TestRedis_Data {

    @Autowired//自动装载
    public RedisTemplate<Object, Object> tem;

    @Test
    public void test1() {
        // tem.setConnectionFactory(connectionFactory);
        // RedisTemplate
        DeptBean dept = new DeptBean(10, "傻强", "上海");
        tem.opsForValue().set("mydeptsingle", dept);//直接可以设置对象,将其进行序列化
        DeptBean object = (DeptBean) tem.opsForValue().get("mydeptsingle");// 底层已经序列化了
        System.out.println(object.getDeptno() + " " + object.getDname() + "  " + object.getLoc());
    }

}

然后在对自己有缓存需求的方法进行开启Redis缓存,

//@Controller 
@RestController //相当于@Controller 和 @ResponseBody 相结合的功能 
public class DeptController {

    @Autowired //自动装载
    private DeptDao dao;

    //使用redis
    @Autowired
    private RedisTemplate<Object, Object> temp;

    @RequestMapping(value = "/dept/all", method = RequestMethod.GET) // @ResponseBody
    public List<DeptBean> selectAll() {
        List<DeptBean> Deptlist = (List<DeptBean>) temp.opsForValue().get("Deptlist");
        List<DeptBean> list = null;
        if (Deptlist.isEmpty()) {
            list = dao.findAll();
            temp.opsForValue().set("Deptlist", list);
            return list;
        }
        return Deptlist;
    }

    // 查询
    @RequestMapping(value = "/dept/get", method = RequestMethod.GET)
    public DeptBean selelctDeptById(@RequestParam("no") int id) {
        // 从Redis中取出来
        DeptBean bean = (DeptBean) temp.opsForValue().get("dept" + id);
        // 如果没有,从数据库中取出来并返回
        if (bean == null) {
            System.out.println("从数据库中取");
            DeptBean findbean = dao.findId(id);
            temp.opsForValue().set("dept" + id, findbean);
            return findbean;
        }
        System.out.println("从缓存中取的数据");
        return bean;
    }

    // 分页查询
    // 骑牛地址: http://localhost:8060/Spring_Mybatis02/dept/list?page=3&size=3
    @RequestMapping(value = "/dept/list", method = RequestMethod.GET)
    public PageBean pageSelect(
            @RequestParam(defaultValue = "1", required = false) int page,
            @RequestParam(defaultValue = "5", required = false) int size) {
        Page p = PageHelper.startPage(page, size);// 引入jar包中的jar文件,分页只对下一条查询代码有作用
        
        
        List<DeptBean> list = dao.findAll();
        System.out.println("当前页" + p.getPageNum() + "  总页数" + p.getPages() + "  总记录数" + p.getTotal());
        PageBean bean = new PageBean();
        bean.setList(list);
        bean.setPagesize(size);
        bean.setTotalpages(p.getPages());
        bean.setTotalRecords(p.getTotal());
        return bean;
    }

    // 删除
    @RequestMapping(value = "/dept/delete", method = RequestMethod.POST)
    public int deleteDeptById(int deptno) {
        //删除缓存
        temp.delete("dept" + deptno);
        //从数据库删除
        return dao.deleteDeptById(deptno);
    }
}

 当然如果你需要在项目启动时候就加载到内存中,则可以这样,另写一个专门加载需要缓存的数据

@Component
public class InitLoadData {
    @Resource //装载dao层
    private DeptDao dao;
    @Resource
    private RedisTemplate<Object,Object> temp;  //装载Redis中的bean配置
    
    @PostConstruct//项目启动时候就会启动该方法 的注解
    public void inint(){
        System.out.println("查询数据库将数据加载到Redis中");
        DeptBean dept=dao.findId(10);
        temp.opsForValue().set("dept10", dept);
        
    }
}