在网上看了很多资料，发现例子都是千篇一律的相互复制。而且，使用的都是jedis的客户端。。我这里使用的是redistemplate类实现。
缓存的原理。。实现cache类接口，当哪个类需要缓存的时候，就直接将cache标签引入，并且制定我们的缓存类就可以了。
上代码：
1、引入spring-data-redis
1 <!-- redis服务 start--> 2 <dependency> 3 <groupId>org.springframework.data</groupId> 4 <artifactId>spring-data-redis</artifactId> 5 <version>1.6.2.RELEASE</version> 6 </dependency>
2、java缓存类，至于里面如何获取bean，ApplicationUtil.getBean("redisTemplate")，请查看我上篇文章：普通java类获取springbean的方法
1 package com.iafclub.demo.cache;
2
3 import java.io.Serializable;
4 import java.util.Set;
5 import java.util.concurrent.TimeUnit;
6 import java.util.concurrent.locks.ReadWriteLock;
7 import java.util.concurrent.locks.ReentrantReadWriteLock;
8
9 import org.apache.commons.codec.digest.DigestUtils;
10 import org.apache.ibatis.cache.Cache;
11 import org.apache.log4j.Logger;
12 import org.springframework.dao.DataAccessException;
13 import org.springframework.data.redis.connection.RedisConnection;
14 import org.springframework.data.redis.core.RedisCallback;
15 import org.springframework.data.redis.core.RedisTemplate;
16 import org.springframework.data.redis.serializer.JdkSerializationRedisSerializer;
17
18 import com.iafclub.demo.util.ApplicationUtil;
19
20 /**
21 * 使用第三方缓存服务器，处理二级缓存
22 * 缓存时间在putObject中设置
23 *
24 * @author chenweixian
25 *
26 */
27 public class RedisCache implements Cache {
28 private static final Logger logger = Logger.getLogger(RedisCache.class);
29
30 private final ReadWriteLock readWriteLock = new ReentrantReadWriteLock(true);
31
32 private final String COMMON_CACHE_KEY = "demo:MYBATIS:";
33
34 private String id;
35
36 private JdkSerializationRedisSerializer jdkSerializer = new JdkSerializationRedisSerializer();
37 /**所有key*/
38 private String getKeys() {
39 return COMMON_CACHE_KEY + this.id + ":*";
40 }
41 /**
42 * 按照一定规则标识key
43 */
44 private String getKey(Object key) {
45 return COMMON_CACHE_KEY + this.id + ":"+DigestUtils.md5Hex(String.valueOf(key));
46 }
47
48 public RedisTemplate<String, Serializable> getRedisTemplate(){
49 return (RedisTemplate<String, Serializable>) ApplicationUtil.getBean("redisTemplate");
50 }
51
52 public RedisCache(final String id) {
53 if (id == null) {
54 throw new IllegalArgumentException("必须传入ID");
55 }
56 logger.debug("MybatisRedisCache:id=" + id);
57 this.id = id;
58 }
59
60 @Override
61 public String getId() {
62 return this.id;
63 }
64
65 @Override
66 public void putObject(Object key, Object value) {
67 if (getRedisTemplate()==null){
68 return ;
69 }
70 if (value != null) {
71 getRedisTemplate().opsForValue().set(getKey(key),
72 jdkSerializer.serialize(value), 20, TimeUnit.SECONDS);
73 }
74 }
75
76 @Override
77 public Object getObject(Object key) {
78 if (getRedisTemplate()==null){
79 return null;
80 }
81 try {
82 if (key != null) {
83 Object obj = getRedisTemplate().opsForValue().get(getKey(key));
84 return jdkSerializer.deserialize((byte[]) obj);
85 }
86 } catch (Exception e) {
87 logger.error("redis ");
88 }
89 return null;
90 }
91
92 @Override
93 public Object removeObject(Object key) {
94 if (getRedisTemplate()==null){
95 return null;
96 }
97 try {
98 if (key != null) {
99 getRedisTemplate().delete(getKey(key));
100 logger.debug("从缓存中移除-----"+this.id);
101 }
102 } catch (Exception e) {
103 }
104 return null;
105 }
106
107 @Override
108 public void clear() {
109 if (getRedisTemplate()==null){
110 return ;
111 }
112 try {
113 Set<String> keys = getRedisTemplate().keys(getKeys());
114 getRedisTemplate().delete(keys);
115 logger.debug("出现新增、修改、删除操作，清空对应Mapper缓存======>"+keys.size());
116 } catch (Exception e) {
117 logger.error(e.getMessage(), e);
118 }
119 }
120
121 @Override
122 public int getSize() {
123 if (getRedisTemplate()==null){
124 return 0;
125 }
126 Long size = getRedisTemplate().execute(
127 new RedisCallback<Long>() {
128 @Override
129 public Long doInRedis(RedisConnection connection)
130 throws DataAccessException {
131 return connection.dbSize();
132 }
133 });
134 return size.intValue();
135 }
136
137 @Override
138 public ReadWriteLock getReadWriteLock() {
139 return this.readWriteLock;
140 }
141 }
3、mybatis配置：注意加粗标红，斜线部分:
21 <!-- redis缓存 --> 22 <cache type="com.iafclub.demo.cache.RedisCache" eviction="LRU" />
1 <?xml version="1.0" encoding="UTF-8" ?>
2 <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
3 <mapper namespace="com.iafclub.demo.dao.DictionaryMapper" >
4 <resultMap id="BaseResultMap" type="com.iafclub.demo.domain.Dictionary" >
5 <id column="auto_id" property="autoId" jdbcType="VARCHAR" />
6 <result column="type_id" property="typeId" jdbcType="VARCHAR" />
7 <result column="type_name" property="typeName" jdbcType="VARCHAR" />
8 <result column="field_key" property="fieldKey" jdbcType="VARCHAR" />
9 <result column="field_value" property="fieldValue" jdbcType="VARCHAR" />
10 <result column="field_back" property="fieldBack" jdbcType="VARCHAR" />
11 <result column="field_back2" property="fieldBack2" jdbcType="VARCHAR" />
12 <result column="field_back3" property="fieldBack3" jdbcType="VARCHAR" />
13 <result column="remark" property="remark" jdbcType="VARCHAR" />
14 <result column="editor" property="editor" jdbcType="VARCHAR" />
15 <result column="edittime" property="edittime" jdbcType="TIMESTAMP" />
16 </resultMap>
17 <sql id="Base_Column_List" >
18 auto_id, type_id, type_name, field_key, field_value, field_back, field_back2, field_back3,
19 remark, editor, edittime
20 </sql>
21 <!-- redis缓存 -->
22 <cache type="com.iafclub.demo.cache.RedisCache" eviction="LRU" />
23 <select id="selectByPrimaryKey" resultMap="BaseResultMap" parameterType="java.lang.String" >
24 select
25 <include refid="Base_Column_List" />
26 from t_dictionary
27 where auto_id = #{autoId}
28 </select>
29 <select id="selectAll" resultMap="BaseResultMap" parameterType="java.lang.String" >
30 select
31 <include refid="Base_Column_List" />
32 from t_dictionary limit 200
33 </select>
34 </mapper>
4、mybatis配置：
1 <?xml version="1.0" encoding="UTF-8" ?> 2 <!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd"> 3 <configuration> 4 <settings> 5 <!-- 开启缓存 --> 6 <setting name="cacheEnabled" value="true"/> 7 <!-- Java属性与数据库字段采用驼峰式对应 --> 8 <setting name="mapUnderscoreToCamelCase" value="true" /> 9 </settings> 10 <!-- 11 <settings> 12 <setting name="useColumnLabel" value="true"/> 13 <setting name="useGeneratedKeys" value="false"/> 14 <setting name="cacheEnabled" value="true" /> 这个配置使全局的映射器启用或禁用缓存 15 <setting name="multipleResultSetsEnabled" value="true"/>对于未知的SQL查询，允许返回不同的结果集以达到通用的效果 16 <setting name="defaultExecutorType" value="REUSE" />配置默认的执行器。SIMPLE 执行器没有什么特别之处。REUSE 执行器重用预处理语句。BATCH 执行器重用语句和批量更新 17 <setting name="lazyLoadingEnabled" value="false" />全局启用或禁用延迟加载。当禁用时，所有关联对象都会即时加载 18 <setting name="aggressiveLazyLoading" value="true" /> 19 <setting name="enhancementEnabled" value="true"/> 20 <setting name="defaultStatementTimeout" value="25000" /> 设置超时时间，它决定驱动等待一个数据库响应的时间。 21 </settings> 22 --> 23 </configuration>
5、其他页面实现，次要。。。
n、测试运行结果：只有第一次查询，发送了sql，第二次后，就不会发送sql，直接在redis中查询。如果进行增删改，都会清空，然后，再发sql
时间： 2024-12-10 22:12:49