Google Guava Cache 示列

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google guava cache

引用maven依赖

<!-- https://mvnrepository.com/artifact/com.google.guava/guava --><dependency>    <groupId>com.google.guava</groupId>    <artifactId>guava</artifactId>    <version>18.0</version></dependency>

java代码

import com.google.common.cache.CacheBuilder;import com.google.common.cache.CacheLoader;import com.google.common.cache.LoadingCache;import java.util.concurrent.ExecutionException;import java.util.concurrent.TimeUnit;/** * Created by zhengyong on 16/10/9. */public class GuavaCacheTest {    private static LoadingCache<String, String> graphs = null;    public static void main(String[] args) {        loadDataToCache();        // 第一次从数据源获取,并缓存        String value1 = getValue("mykey");        // 第二次从缓存获取        String value2 = getValue("mykey");        // 过期重新从数据源加载进缓存        try {            Thread.sleep(10);        } catch (InterruptedException e) {            e.printStackTrace();        }        String value3 = getValue("mykey");        String value4 = getValue("mykey");        String value5 = getValue("mykey2");        String value6 = getValue("mykey2");    }    /**     * 根据key获取值     *      * @param key 查询条件key     * @return 返回value值     */    private static String getValue(String key) {        String resultVal = null;        try {            resultVal = graphs.get(key);        } catch (ExecutionException e) {            e.printStackTrace();        }        System.out.println(String.format("get key=%s return value=%s", key, resultVal));        return resultVal;    }    /**     * 声明加载数据源方式     */    private static void loadDataToCache() {        graphs = CacheBuilder.newBuilder().maximumSize(1000).expireAfterWrite(10, TimeUnit.MILLISECONDS).build(new CacheLoader<String, String>() {          public String load(String key) {              // 这里是key根据实际去取值的方法              System.out.println(String.format("load '%s' from database...",                                               key));              return "value_" + key;          }      });    }}

运行结果

load 'mykey' from database...get key=mykey return value=value_mykeyget key=mykey return value=value_mykeyload 'mykey' from database...get key=mykey return value=value_mykeyget key=mykey return value=value_mykeyload 'mykey2' from database...get key=mykey2 return value=value_mykey2get key=mykey2 return value=value_mykey2

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