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4 Java注解：一个真实的Elasticsearch案例

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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;}@Overridepublic 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@Autowiredprivate 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<Field> 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<Field> 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;}}

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