Guava------------Cache
简单从这几个方面描述一下如何使用Cache，对Cache的各种原理介绍此处不涉及.
1.使用场景
2.如何使用Cache
3.创建方式
4. 如何和Spring搭配使用
+------------------------------------------------------分割心吖-------------------------------------------------------+
1. Cache的使用场景
一般而言，对于那些频繁需要查询比对的热点数据，我们采用使用缓存，对于数据量较小的，几条，几十条数据，而且需要加缓存的接口较少，这时候我们会采用Cache,建议使用Google提供的guava Cache，它简单易用的同时，性能也好. 而且线程安全（原因看源码） .对于那些较大数据量的，或者需要加缓存的接口较多的项目，可以去考虑Redis，memcached等等
2. 如何使用Cache
和Map的使用方式差不多，也可以和Spring结合，使用@Cacheable注解使用.
3. 创建方式
1. Cache Callable
2. LoadingCache
方式一：
1 package info.sanaulla.cache;
2
3 import com.google.common.cache.Cache;
4 import com.google.common.cache.CacheBuilder;
5 import org.junit.Test;
6
7 import java.util.concurrent.Callable;
8 import java.util.concurrent.ExecutionException;
9 import java.util.concurrent.TimeUnit;
10
11 /**
12 * *********************************************************
13 * <p/>
14 * Author: XiJun.Gong
15 * Date: 2016-08-17 16:59
16 * Version: default 1.0.0
17 * Class description：
18 * <p/>
19 * *********************************************************
20 */
21 public class CacheDemo {
22 private static Cache<Object, Object> cache = CacheBuilder.newBuilder()
23 .maximumSize(100).expireAfterWrite(24, TimeUnit.HOURS)
24 .recordStats()
25 .build();
26
27 public static Object get(Object key) throws ExecutionException {
28
29 Object var = cache.get(key, new Callable<Object>() {
30 @Override
31 public Object call() throws Exception {
32 System.out.println("如果没有值,就执行其他方式去获取值");
33 String var = "Google.com.sg";
34 return var;
35 }
36 });
37 return var;
38 }
39
40 public static void put(Object key, Object value) {
41 cache.put(key, value);
42 }
43
44 class Person {
45 private String name;
46 private Integer age;
47
48 public Person() {
49 }
50
51 public Person(String name, Integer age) {
52 this.name = name;
53 this.age = age;
54 }
55
56 public String getName() {
57 return name;
58 }
59
60 public void setName(String name) {
61 this.name = name;
62 }
63
64 public Integer getAge() {
65 return age;
66 }
67
68 public void setAge(Integer age) {
69 this.age = age;
70 }
71
72 @Override
73 public String toString() {
74 return "Person{" +
75 "名字='" + name + '/'' +
76 ", 年纪=" + age +
77 '}';
78 }
79 }
80
81 @Test
82 public void CacheTest() throws ExecutionException {
83
84 Person person = new Person();
85 person.setAge(11);
86 person.setName("tSun");
87 System.out.println(CacheDemo.get("man"));
88 CacheDemo.put("man", new Person("hopg", 123));
89 System.out.println(CacheDemo.get("man"));
90 System.out.println(CacheDemo.get("man"));
91
92 System.out.println(CacheDemo.get("person").toString());
93 CacheDemo.put("person", person);
94 System.out.println(CacheDemo.get("person").toString());
95 System.out.println(CacheDemo.get("person").toString());
96
97 System.out.println(CacheDemo.get("woman"));
98 CacheDemo.put("women", new Person("google", 666));
99 System.out.println(CacheDemo.get("woman"));
100 System.out.println(CacheDemo.get("woman"));
101 System.out.println(CacheDemo.get("man"));
102 }
103 }
View Code
结果：
1 如果没有值,就执行其他方式去获取值
2 Google.com.sg
3 Person{名字='hopg', 年纪=123}
4 Person{名字='hopg', 年纪=123}
5 如果没有值,就执行其他方式去获取值
6 Google.com.sg
7 Person{名字='tSun', 年纪=11}
8 Person{名字='tSun', 年纪=11}
9 如果没有值,就执行其他方式去获取值
10 Google.com.sg
11 Google.com.sg
12 Google.com.sg
13 Person{名字='hopg', 年纪=123}
方式二：
1 package info.sanaulla.cache;
2
3 import com.google.common.cache.CacheBuilder;
4 import com.google.common.cache.CacheLoader;
5 import com.google.common.cache.LoadingCache;
6 import org.junit.Test;
7
8 import java.util.concurrent.ExecutionException;
9 import java.util.concurrent.TimeUnit;
10
11 /**
12 * *********************************************************
13 * <p/>
14 * Author: XiJun.Gong
15 * Date: 2016-08-17 15:00
16 * Version: default 1.0.0
17 * Class description：
18 * <p>Cache Demo</p>
19 * <p/>
20 * *********************************************************
21 */
22 public class CacheUtil {
23
24
25 private static LoadingCache<Object, Object> cache = CacheBuilder.newBuilder()
26 .maximumSize(2)
27 .expireAfterAccess(24, TimeUnit.HOURS)
28 .recordStats()
29 .build(new CacheLoader<Object, Object>() {
30
31 @Override
32 public Object load(Object key) throws Exception {
33 return key;
34 }
35 });
36
37 public static Object get(Object key) throws ExecutionException {
38 Object var = cache.get(key);
39
40 if (var.equals(key)) {
41
42 System.out.println("执行其他操作,查询该值");
43 /**执行其他操作，获取值**/
44 Object object = "Google.com.hk";
45 put(key, object);
46 } else {
47 System.out.println("从Cache中取值....");
48 }
49 return cache.get(key);
50 }
51
52 public static void put(Object key, Object value) {
53 cache.put(key, value);
54 }
55
56 class Person {
57 private String name;
58 private Integer age;
59
60 public Person() {
61 }
62
63 public Person(String name, Integer age) {
64 this.name = name;
65 this.age = age;
66 }
67
68 public String getName() {
69 return name;
70 }
71
72 public void setName(String name) {
73 this.name = name;
74 }
75
76 public Integer getAge() {
77 return age;
78 }
79
80 public void setAge(Integer age) {
81 this.age = age;
82 }
83
84 @Override
85 public String toString() {
86 return "Person{" +
87 "名字='" + name + '/'' +
88 ", 年纪=" + age +
89 '}';
90 }
91 }
92
93 @Test
94 public void TestCache() throws ExecutionException {
95
96 Person person = new Person();
97 person.setAge(11);
98 person.setName("tSun");
99 System.out.println(CacheUtil.get("man"));
100 CacheUtil.put("man", new Person("hopg", 123));
101 System.out.println(CacheUtil.get("man"));
102 System.out.println(CacheUtil.get("man"));
103
104 System.out.println(CacheUtil.get("person").toString());
105 CacheUtil.put("person", person);
106 System.out.println(CacheUtil.get("person").toString());
107 System.out.println(CacheUtil.get("person").toString());
108
109 System.out.println(CacheUtil.get("woman"));
110 CacheUtil.put("women", new Person("google", 666));
111 System.out.println(CacheUtil.get("woman"));
112 System.out.println(CacheUtil.get("woman"));
113 System.out.println(CacheUtil.get("man"));
114 }
115 }
View Code
结果：
1 执行其他操作,查询该值
2 Google.com.hk
3 从Cache中取值....
4 Person{名字='hopg', 年纪=123}
5 从Cache中取值....
6 Person{名字='hopg', 年纪=123}
7 执行其他操作,查询该值
8 Google.com.hk
9 从Cache中取值....
10 Person{名字='tSun', 年纪=11}
11 从Cache中取值....
12 Person{名字='tSun', 年纪=11}
13 执行其他操作,查询该值
14 Google.com.hk
15 从Cache中取值....
16 Google.com.hk
17 从Cache中取值....
18 Google.com.hk
19 执行其他操作,查询该值
20 Google.com.hk
4. 如何和Spring结合使用
4.1 首先简单了解一下@Cacheable,@CachePut,@CacheEvit
对于 cache sql
Cacheable --save/insert
CachePut --update/Insert
CacheEvit --delete
4.2 配置spring配置文件applicationContext.xml
1 <!-- cache --> 2 <bean id="cacheManager" class="com.data.cache.guava.GuavaCacheManager" 3 p:transactionAware="true"> 4 <property name="caches"> 5 <list> 6 <bean class="com.data.cache.guava.GuavaCacheFactoryBean" name="Person-cache"/> 7 <bean class="com.data.cache.guava.GuavaCacheFactoryBean" name="Modules-cache"/> 8 </list> 9 </property> 10 </bean>
部分代码：
1 @Override
2 @Cacheable(value = "Modules-cache")
3 public Collection<Module> getModule(String name) {
4 return module.get(checkNotNull(name));
5 }
6
7 @Override
8 @Transactional(readOnly = false)
9 @CacheEvict(value = "Modules-cache", key = "#modules.name")
10 public void createModule(Modules post) {
11 ModuleDao.create(checkNotNull(module));
12 }
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