昨天把拼了一半的注解+Elasticsearch积木放下了,因为东西太多了拼不好,还容易乱。休息了一晚上接着来。
接着昨天,创建elasticsearch文档注解(相当于数据表的注解):
/** * elastic文档注解,定义每个elasticsearch文档上的属性 * * @author xiangwang */@Inherited@Retention(RetentionPolicy.RUNTIME)@Target({ ElementType.TYPE })public @interface Document { String index(); String type() default "_doc"; boolean useServerConfiguration() default false; short shards() default 1; short replicas() default 0; String refreshInterval() default "1s"; String indexStoreType() default "fs";}
然后再创建elasticsearch文档(相当于数据表):
/** * elastic文档对象 * * @author xiangwang */@Document(index = "document", type = "_doc", shards = 1, replicas = 0)public class ElasticDocument { private static final long serialVersionUID = 2879048112350101009L; // 文档编码 @DocField(name = "guid", type = FieldType.Keyword) protected String guid = ""; // 标题 @DocField(name = "title", type = FieldType.Text, analyzer = "ik_max_word", searchAnalyzer = "ik_max_word") protected String title = ""; // 文档创建时间(资源实际创建时间) @DocField(name = "createtime", type = FieldType.Long) protected long createtime; // 文档更新时间(资源实际更新时间) @DocField(name = "updatetime", type = FieldType.Long) protected long updatetime; public ElasticDocument() { } public String getGuid() { return guid; } public void setGuid(String guid) { this.guid = guid; } public String getTitle() { return title; } public void setTitle(String title) { this.title = title; } public long getCreatetime() { return createtime; } public void setCreatetime(long createtime) { this.createtime = createtime; } public long getUpdatetime() { return updatetime; } public void setUpdatetime(long updatetime) { this.updatetime = updatetime; } @Override public String toString() { return String.format("{\"guid\":\"%s\", \"title\":\"%s\", \"createtime\":%d, " + "\"updatetime\":%d}", guid, title, createtime, updatetime); }}
这里面的@Document就是刚才创建的文档注解。
最后,创建一个真正的执行者,就由它来完成所有材料的拼装:
/** * ElasticDao * * @author xiangwang */@Componentpublic class ElasticDao { // ElasticConfiguration中定义的Bean对象 @Autowired private RestHighLevelClient client; /** * 索引是否存在 * */ public boolean indexExist(final String index) { try { return client.indices().exists(new GetIndexRequest(index), RequestOptions.DEFAULT); } catch (IOException e) { System.out.println("index exist exception"); } return false; } /** * 解析类注解,获取包括父类字段在内的所有字段 * 因为解析的时候,会把父类及自身的一些额外字段给解析进去 * 如logger、serialVersionUID等 * 所以需要把这些无用的字段排除掉 * 这里不存在继承,所以直接调用clazz.getDeclaredFields() * 另外,如果存在继承关系,该怎么处理呢?(可以思考一下) * */ public static List getAllDeclaredFields(Class clazz) { return new ArrayList(Arrays.asList(clazz.getDeclaredFields())); } /** * 创建索引,前面都是为了实现它作准备 * 这里会通过注解,一路解析文档的字段,拼接成可执行的脚本交给elasticsearch的api去执行 * */ public boolean createIndex(final String index, final Class clazz) { try { Document document = (Document) clazz.getAnnotation(Document.class); int shards = document.shards(); int replicas = document.replicas(); if (indexExist(index)) { return false; } CreateIndexRequest request = new CreateIndexRequest(index); request.settings(Settings.builder() .put("index.number_of_shards", shards) .put("index.number_of_replicas", replicas) ); StringBuilder builder = new StringBuilder(); builder.append("{\n"); builder.append(" \"properties\": {\n"); List list = getAllDeclaredFields(clazz); int length = list.size(); for (int i = 0; i < length; i++) { DocField docField = list.get(i).getAnnotation(DocField.class); if (null == docField) { continue; } builder.append(" \"").append(docField.name()).append("\" : {\n"); builder.append(" \"type\" : \"").append(docField.type().value).append("\""); if (docField.index()) { builder.append(", \n"); builder.append(" \"index\" : ").append(docField.index()); } if (docField.fielddata()) { builder.append(", \n"); builder.append(" \"fielddata\" : ").append(docField.fielddata()); } if (docField.store()) { builder.append(", \n"); builder.append(" \"store\" : ").append(docField.store()); } if (StringUtils.isNotBlank(docField.analyzer())) { builder.append(", \n"); builder.append(" \"analyzer\" : \"").append(docField.analyzer()).append("\""); } if (StringUtils.isNotBlank(docField.format())) { builder.append(", \n"); builder.append(" \"format\" : \"").append(docField.format()).append("\""); } if (StringUtils.isNotBlank(docField.searchAnalyzer())) { builder.append(", \n"); builder.append(" \"search_analyzer\" : \"").append(docField.searchAnalyzer()).append("\""); } if (StringUtils.isNotBlank(docField.pattern())) { builder.append(", \n"); builder.append(" \"pattern\" : \"").append(docField.pattern()).append("\""); } if (StringUtils.isNotBlank(docField.normalizer())) { builder.append(", \n"); builder.append(" \"normalizer\" : \"").append(docField.normalizer()).append("\""); } if (i == length -1) { builder.append("\n }\n"); } else { builder.append("\n }, \n"); } } builder.append(" }\n"); builder.append("}\n"); request.mapping(JSON.parseObject(builder.toString()).toJSONString(), XContentType.JSON); CreateIndexResponse response = client.indices().create(request, RequestOptions.DEFAULT); boolean acknowledged = response.isAcknowledged(); return acknowledged; } catch (IOException e) { System.out.println("create index exception"); } return false; }}
好了,现在该搭个台子让这个执行者上台表演了:
/** * 索引Service实现 * * @author xiangwang */@Servicepublic class IndexService { @Resource private ElasticDao elasticDao; /** * 索引初始化 * * 这个方法可以在启动应用时调用,可以在接口中调用,也可以在main方法中调用 */ @PostConstruct private void initIndex() { boolean flag = false; // 创建一个名为Test的索引 if (!elasticDao.indexExist("Test")) { flag = elasticDao.createIndex("Test", ElasticDocument.class); if (flag) { System.out.println("create Test index success"); } else { System.out.println("create Test index failure"); } } else { System.out.println("Test index exist"); } }}
这就是整个注解结合Elasticsearch的真实案例。
其实这玩意一开始只是作为代码里面的小工具,但到后来随着需求越来越多,越来越变态,在我们后来的系统中它发展成了一个内部的小系统,可以通过管理后台的功能按钮来动态创建、修改、删除Elasticsearch的索引和文档,以及导出、导入数据等等功能,既非常强大,也非常方便。
我想,那些目前主流开发的框架也都是这么从小做起,一点点发展起来的吧。