引入依赖
<dependency> <groupId>org.mongodb</groupId> <artifactId>mongodb-driver</artifactId> <version>3.4.1</version> </dependency> <dependency> <groupId>org.mongodb</groupId> <artifactId>bson</artifactId> <version>3.4.1</version> </dependency>直接撸代码 创建注解类 Column，NotColumn两个
Column
import java.lang.annotation.ElementType; import java.lang.annotation.Retention; import java.lang.annotation.RetentionPolicy; import java.lang.annotation.Target; @Target(ElementType.FIELD) @Retention(RetentionPolicy.RUNTIME) public @interface Column { public String name(); public String text() default "这是一个属性映射"; }NotColumn
import java.lang.annotation.ElementType; import java.lang.annotation.Retention; import java.lang.annotation.RetentionPolicy; import java.lang.annotation.Target; @Target(ElementType.FIELD) @Retention(RetentionPolicy.RUNTIME) public @interface NotColumn { public String text() default "不是属性字段"; }创建BsonUtil类
import com.mongodb.client.MongoCollection; import com.mongodb.client.MongoCursor; import org.bson.Document; import java.lang.reflect.Field; import java.lang.reflect.InvocationTargetException; import java.lang.reflect.Method; import java.lang.reflect.ParameterizedType; import java.util.ArrayList; import java.util.List; /* * 将mongo的文档转化为对象将对象转化为mongo文档 * @author:zhoub */ public class BsonUtil { /** * 将Document列换转换JavaList * @param documents * @param clazz * @param <T> * @return * @throws IllegalArgumentException * @throws InstantiationException * @throws IllegalAccessException * @throws InvocationTargetException */ public static <T> List<T> toBeans(List<Document> documents, Class<T> clazz) throws IllegalArgumentException, InstantiationException, IllegalAccessException, InvocationTargetException { List<T> list = new ArrayList<T>(); for (int i = 0; null != documents && i < documents.size(); i++) { list.add(toBean(documents.get(i), clazz)); } return list; } /* * 将Bson 转化为对象 * * @param:Bson文档 * * @param:类pojo * * @param:返回对象 */ public static <T> T toBean(Document document, Class<T> clazz) throws InstantiationException, IllegalAccessException, IllegalArgumentException, InvocationTargetException { T obj = clazz.newInstance();// 声明一个对象 Field[] fields = clazz.getDeclaredFields();// 获取所有属性 Method[] methods = clazz.getMethods();// 获取所有的方法 /* * 查找所有的属性，并通过属性名和数据库字段名通过相等映射 */ for (int i = 0; i < fields.length; i++) { String fieldName = fields[i].getName(); Column column = fields[i].getAnnotation(Column.class); Object bson = null; if (null != column && null != column.name()) { bson = document.get(column.name()); } else if ("id".equals(fieldName)) { bson = document.get("_id"); } else { bson = document.get(fieldName); } if (null == bson) { continue; } else if (bson instanceof Document) {// 如果字段是文档了递归调用 bson = toBean((Document) bson, fields[i].getType()); } else if (bson instanceof MongoCollection) {// 如果字段是文档集了调用colTOList方法 bson = colToList(bson, fields[i]); } for (int j = 0; j < methods.length; j++) {// 为对象赋值 String metdName = methods[j].getName(); if (equalFieldAndSet(fieldName, metdName)) { methods[j].invoke(obj, bson); break; } } } return obj; } public static List<Document> toBsons(List<Object> objs) throws IllegalArgumentException, SecurityException, IllegalAccessException, InvocationTargetException, NoSuchFieldException { List<Document> documents = new ArrayList<Document>(); for (int i = 0; null != objs && i < objs.size(); i++) { documents.add(toBson(objs.get(i))); } return documents; } /* * 将对象转化为Bson文档 * @param:对象 * @param:类型 * @return:文档 */ public static Document toBson(Object obj) throws IllegalArgumentException, IllegalAccessException, InvocationTargetException, SecurityException, NoSuchFieldException { if (null == obj) { return null; } Class<? extends Object> clazz = obj.getClass(); Document document = new Document(); Method[] methods = clazz.getDeclaredMethods(); Field[] fields = clazz.getDeclaredFields(); for (int i = 0; null != fields && i < fields.length; i++) { Column column = fields[i].getAnnotation(Column.class);// 获取列注解内容 NotColumn notColumn = fields[i].getAnnotation(NotColumn.class);// 获取否列 String key = null;// 对应的文档键值 if (null != column && null != column.name()) {// 存在列映射取值 key = column.name(); } else if (null != notColumn) {// 不是列的情况 continue; } else { key = fields[i].getName();// 默认情况通过属性名映射 if ("id".equals(key)) {// 替换id为_id key = "_id"; } } String fieldName = fields[i].getName(); /* * 获取对象属性值并映射到Document中 */ for (int j = 0; null != methods && j < methods.length; j++) { String methdName = methods[j].getName(); if (null != fieldName && equalFieldAndGet(fieldName, methdName)) { Object val = methods[j].invoke(obj);// 得到值 if (null == val) { continue; } if (isJavaClass(methods[j].getReturnType())) { if (methods[j].getReturnType().getName() .equals("java.util.List")) {// 列表处理 @SuppressWarnings("unchecked") List<Object> list = (List<Object>) val; List<Document> documents = new ArrayList<Document>(); for (Object obj1 : list) { documents.add(toBson(obj1)); } document.append(key, documents); } else {// 其它对象处理，基本类型 document.append(key, val); } } else {// 自定义类型 document.append(key, toBson(val)); } } } } return document; } /* * 是否是自定义类型】 * * false:是自定义 */ private static boolean isJavaClass(Class<?> clz) { return clz != null && clz.getClassLoader() == null; } /* * 将文档集转化为列表 * * @param:文档集 * * @param:属性类型 * * @return:返回列表 */ private static List<Object> colToList(Object bson, Field field) throws InstantiationException, IllegalAccessException, IllegalArgumentException, InvocationTargetException { ParameterizedType pt = (ParameterizedType) field.getGenericType();// 获取列表的类型 List<Object> objs = new ArrayList<Object>(); @SuppressWarnings("unchecked") MongoCollection<Document> cols = (MongoCollection<Document>) bson; MongoCursor<Document> cursor = cols.find().iterator(); while (cursor.hasNext()) { Document child = cursor.next(); @SuppressWarnings("rawtypes") Class clz = (Class) pt.getActualTypeArguments()[0];// 获取元素类型 @SuppressWarnings("unchecked") Object obj = toBean(child, clz); System.out.println(child); objs.add(obj); } return objs; } /* * 比较setter方法和属性相等 */ private static boolean equalFieldAndSet(String field, String name) { if (name.toLowerCase().matches("set" + field.toLowerCase())) { return true; } else { return false; } } /* * 比较getter方法和属性相等 */ private static boolean equalFieldAndGet(String field, String name) { if (name.toLowerCase().matches("get" + field.toLowerCase())) { return true; } else { return false; } } }—————————————————————————————————————————————————————————————
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此处为Scala编写
object DataOutPutToDB { lazy val conn: MongoCollection[Document] = getConnection("127.0.0.1", 27017, "mytest", "track", "root", "root") def getConnection(host: String, port: Int, dbName: String, name: String, username: String, password: String): MongoCollection[Document] = { val adds: List[ServerAddress] = new util.ArrayList[ServerAddress] //ServerAddress()两个参数分别为 服务器地址 和 端口 val serverAddress: ServerAddress = new ServerAddress(host, port) adds.add(serverAddress) val credentials: List[MongoCredential] = new util.ArrayList[MongoCredential] //MongoCredential.createScramSha1Credential()三个参数分别为 用户名 数据库名称 密码 val mongoCredential: MongoCredential = MongoCredential.createScramSha1Credential(username, dbName, password.toCharArray) credentials.add(mongoCredential) //通过连接认证获取MongoDB连接 val mongoClient: MongoClient = new MongoClient(adds, credentials) //连接到数据库 val mongoDatabase: MongoDatabase = mongoClient.getDatabase(dbName) val value: MongoCollection[Document] = mongoDatabase.getCollection(name) value }