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系统实现缓存有多种方式，如redis，ehcache，Memcached，在项目开发中，使用另外一种实现方式使用xml配置文件和XStream方式实现缓存，原理是数据放在内存中。思路是：定义一个全局静态变量Map，将数据保存在map中即可。
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步骤一：配置xml文件
<?xml version="1.0" encoding="UTF-8" ?>
<webcache>
<cache>
<name>CACHE_DICT</name>
<descript>数据字典</descript>
<datasource></datasource>
<sql><![CDATA[]]></sql>
<mapperid>vc.cache.mapper.CACHE_DICT</mapperid>
<type>DICT</type>
</cache>
</webcache>
步骤二：建对应的实体类
@XStreamAlias("webcache") // XStream的别名注解，在xml文件对应标签名
public class WebCacheXmlBean {
@XStreamImplicit // 集合注解，只能用在集合属性上
List<CacheXmlBean> cacheList;
public List<CacheXmlBean> getCacheList() {
return cacheList;
}
public void setCacheList(List<CacheXmlBean> cacheList) {
this.cacheList = cacheList;
}
}
@XStreamAlias("cache")
public class CacheXmlBean {
public static final String CACHE_TYPE_DICT = "DICT";
public static final String CACHE_TYPE_DATA = "DATA";
private String name;
private String descript;
private String datasource;
private String sql;
private String mapperid;
private String type;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getDescript() {
return descript;
}
public void setDescript(String descript) {
this.descript = descript;
}
public String getDatasource() {
return datasource;
}
public void setDatasource(String datasource) {
this.datasource = datasource;
}
public String getSql() {
return sql;
}
public void setSql(String sql) {
this.sql = sql;
}
public String getMapperid() {
return mapperid;
}
public void setMapperid(String mapperid) {
this.mapperid = mapperid;
}
public String getType() {
return type;
}
public void setType(String type) {
this.type = type;
}
}
步骤三：将xml配置信息转化为bean
public static Map<String, List> DATA_CACHES = new HashMap<>(); public void dictCache(){ XStream xStream = new XStream(); xStream.autodetectAnnotations(true); //自动扫描注解
xStream.processAnnotations(new Class[]{WebCacheXmlBean.class, CacheXmlBean.class}); // 扫描实体类
File file = new File("f:/ETOM/pmms/pmms/src/test/resources/dict.xml"); WebCacheXmlBean webCacheXmlBean = (WebCacheXmlBean) xStream.fromXML(file); List<CacheXmlBean> cacheXmlList = webCacheXmlBean.getCacheList(); for (CacheXmlBean cacheXmlBean : cacheXmlList) { String cacheName = cacheXmlBean.getName(); String mapperid = cacheXmlBean.getMapperid(); String sql = cacheXmlBean.getSql(); List cacheList = null; if(StringUtil.isNotEmpty(mapperid)){ cacheList = dao.find(mapperid); }else if(StringUtil.isNotEmpty(sql)){ cacheList = dao.findBySQL(sql); } logger.info("load cache 【"+cacheName+"】"); if(cacheList != null){ DATA_CACHES.put(cacheName, cacheList); } } }
