① 批量插入4个文档到user集合:
db.user.insertMany([ { name: "Alice", age: 25, email: "alice@example.com", hobbies: ["reading", "writing", "music"] }, { name: "John", age: 30, email: "John@qq.com", hobbies: ["reading", "gaming", "traveling"] }, { name: "Jane", age: 25, email: "Jane@qq.com", hobbies: ["sports", "music", "cooking"] }, { name: "Mike", age: 35, email: "Mike@qq.com", hobbies: ["reading", "writing", "painting"] } ]); ② SpringBoot整合MongoDB实现批量插入文档:
org.springframework.boot spring-boot-starter-data-mongodb @AllArgsConstructor @NoArgsConstructor @Data @Document(collection = "user") public class User { @Id private String id; private String name; private Integer age; private String email; private List hobbies; public User(String name,Integer age,String email,List hobbies){ this.name = name; this.age = age; this.email = email; this.hobbies = hobbies; } } @SpringBootTest @RunWith(SpringRunner.class) public class BeanLoadServiceTest { @Autowired private MongoTemplate mongoTemplate; @Test public void insertUser() { List users = Arrays.asList( new User("Alice", 25, "alice@example.com",Arrays.asList("reading", "writing", "music")), new User("John", 30, "John@qq.com", Arrays.asList("reading", "gaming", "traveling")), new User("Jane", 25, "Jane@qq.com", Arrays.asList("sports", "music", "cooking")), new User("Mike", 35, "Mike@qq.com", Arrays.asList("reading", "writing", "painting")) ); mongoTemplate.insertAll(users); } } 
比较操作符根据数值比较返回数据。MongoDB提供了一些比较查询操作符,用于在查询中进行条件比较。以下是一些常用的比较查询操作符:
$eq:等于,用于匹配字段值等于指定值的文档。
例如:db.collection.find({ field: { $eq: value } })
$ne:不等于,用于匹配字段值不等于指定值的文档。
例如:db.collection.find({ field: { $ne: value } })
$gt:大于,用于匹配字段值大于指定值的文档。
例如:db.collection.find({ field: { $gt: value } })
$gte:大于等于,用于匹配字段值大于等于指定值的文档。
例如:db.collection.find({ field: { $gte: value } })
$lt:小于,用于匹配字段值小于指定值的文档。
例如:db.collection.find({ field: { $lt: value } })
$lte:小于等于,用于匹配字段值小于等于指定值的文档。
例如:db.collection.find({ field: { $lte: value } })
$in:在指定值数组中,用于匹配字段值在指定值数组中的文档。
例如:db.collection.find({ field: { $in: [value1, value2, …] } })
$nin:不在指定值数组中,用于匹配字段值不在指定值数组中的文档。
例如:db.collection.find({ field: { $nin: [value1, value2, …] } })
这些比较查询操作符可以与逻辑操作符(如 a n d 、 and、 and、or、$not等)结合使用,以构建更复杂的查询条件。
用于匹配字段值等于指定值的文档:
db.collection.find({ field: { $eq: value } }) # 相当于 db.collection.find({ field : value}) 查询user集合中name等于Alice的文档:
db.user.find({ name: { $eq: "Alice" } }) @Test public void findUser1() { // 创建查询条件 Criteria criteria = Criteria.where("name").is("Alice"); // 创建查询对象 Query query = new Query(criteria); // 执行查询 List users = mongoTemplate.find(query, User.class); users.forEach(System.out::println); // User(id=668f53342e9dde5bccea0096, name=Alice, age=25, email=alice@example.com, hobbies=[reading, writing, music]) } db.inventory.insertMany( [ { _id: 1, item: { name: "ab", code: "123" }, qty: 15, tags: [ "A", "B", "C" ] }, { _id: 2, item: { name: "cd", code: "123" }, qty: 20, tags: [ "B" ] }, { _id: 3, item: { name: "ij", code: "456" }, qty: 25, tags: [ "A", "B" ] }, { _id: 4, item: { name: "xy", code: "456" }, qty: 30, tags: [ "B", "A" ] }, { _id: 5, item: { name: "mn", code: "000" }, qty: 20, tags: [ [ "A", "B" ], "C" ] } ] ) 查询 inventory 集合中 item 文档的 name 等于 "ab" 的所有文档。要对嵌入式文档中的字段指定条件,使用点符号:
db.inventory.find( { "item.name": { $eq: "ab" } } ) @Data @Document(collection = "inventory") public class Inventory { @Id private String id; private Item item; private int qty; private List 查询 inventory 集合中 tags 数组包含值为 "C" 的元素的所有文档:
db.inventory.find( { tags: { $eq: "B" } } ) @Test public void findUser1() { // 创建查询条件 Criteria criteria = Criteria.where("tags").is("C"); // 创建查询对象 Query query = new Query(criteria); List inventoryList = mongoTemplate.find(query, Inventory.class); inventoryList.forEach(System.out::println); // Inventory(id=1.0, item=Inventory.Item(name=ab, code=123), qty=15, tags=[A, B, C]) // Inventory(id=5.0, item=Inventory.Item(name=mn, code=000), qty=20, tags=[[A, B], C]) } 查询 inventory 集合中 tags 数组与指定数组完全相同或 tags 数组包含数组 [ "A", "B" ] 的所有文档:
db.inventory.find( { tags: { $eq: [ "A", "B" ] } } ) db.inventory.find( { tags: [ "A", "B" ] } ) @Test public void findUser1() { // 创建查询条件 Criteria criteria = Criteria.where("tags").is(Arrays.asList("A","B")); // 创建查询对象 Query query = new Query(criteria); List inventoryList = mongoTemplate.find(query, Inventory.class); inventoryList.forEach(System.out::println); // Inventory(id=3.0, item=Inventory.Item(name=ij, code=456), qty=25, tags=[A, B]) // Inventory(id=5.0, item=Inventory.Item(name=mn, code=000), qty=20, tags=[[A, B], C]) } 用于匹配字段值不等于指定值的文档:
db.collection.find({ field: { $ne: value } }) 查询user集合中name不等于Alice的文档:
db.user.find({ name: { $ne: "Alice" } }) @Test public void findUser2() { // 创建查询条件 Criteria criteria = Criteria.where("name").ne("Alice"); // 创建查询对象 Query query = new Query(criteria); // 执行查询 List users = mongoTemplate.find(query, User.class); users.forEach(System.out::println); // User(id=668f53342e9dde5bccea0097, name=John, age=30, email=John@qq.com, hobbies=[reading, gaming, traveling]) // User(id=668f53342e9dde5bccea0098, name=Jane, age=25, email=Jane@qq.com, hobbies=[sports, music, cooking]) // User(id=668f53342e9dde5bccea0099, name=Mike, age=35, email=Mike@qq.com, hobbies=[reading, writing, painting]) } 用于匹配字段值大于指定值的文档:
db.collection.find({ field: { $gt: value } }) 查询user集合中age大于30的文档:
@Test public void findUser2() { // 创建查询条件 Criteria criteria = Criteria.where("age").gt(30); // 创建查询对象 Query query = new Query(criteria); // 执行查询 List users = mongoTemplate.find(query, User.class); users.forEach(System.out::println); // User(id=668f53342e9dde5bccea0099, name=Mike, age=35, email=Mike@qq.com, hobbies=[reading, writing, painting]) } db.inventory.insertMany( [ { "item": "nuts", "quantity": 30, "carrier": { "name": "Shipit", "fee": 3 } }, { "item": "bolts", "quantity": 50, "carrier": { "name": "Shipit", "fee": 4 } }, { "item": "washers", "quantity": 10, "carrier": { "name": "Shipit", "fee": 1 } } ] ) 查询 inventory 集合中 carrier 文档的 fee 大于 2 的第一个文档,并设置文档的price等于9.99:
db.inventory.updateOne( { "carrier.fee": { $gt: 2 } }, { $set: { "price": 9.99 } } ) @Data @Document(collection = "inventory") public class Inventory { @Id private String id; private String item; private int quantity; private Carrier carrier; @Data public static class Carrier { private String name; private int fee; } } @Test public void updateUser(){ // 创建查询条件 Criteria criteria = Criteria.where("carrier.fee").gt(2); // 创建更新对象 Update update = new Update(); update.set("price", 9.99); // 创建查询对象 Query query = new Query(criteria); // 执行更新操作 UpdateResult updateResult = mongoTemplate.updateFirst(query, update, Inventory.class); } 对应查询结果为:
{ _id: ObjectId("61ba3ec9fe687fce2f042417"), item: 'nuts', quantity: 30, carrier: { name: 'Shipit', fee: 3 }, price: 9.99 }, { _id: ObjectId("61ba3ec9fe687fce2f042418"), item: 'bolts', quantity: 50, carrier: { name: 'Shipit', fee: 4 } }, { _id: ObjectId("61ba3ec9fe687fce2f042419"), item: 'washers', quantity: 10, carrier: { name: 'Shipit', fee: 1 } } 要在carrier.fee 所有大于 2 的文档中设置 price 字段的值,请使用 updateMany()。
用于匹配字段值大于等于指定值的文档:
db.collection.find({ field: { $gte: value } }) 查询user集合中age大于等于30的文档:
@Test public void findUser2() { // 创建查询条件 Criteria criteria = Criteria.where("age").gte(30); // 创建查询对象 Query query = new Query(criteria); // 执行查询 List users = mongoTemplate.find(query, User.class); users.forEach(System.out::println); // User(id=668f53342e9dde5bccea0097, name=John, age=30, email=John@qq.com, hobbies=[reading, gaming, traveling]) // User(id=668f53342e9dde5bccea0099, name=Mike, age=35, email=Mike@qq.com, hobbies=[reading, writing, painting]) } 用于匹配字段值小于指定值的文档:
db.collection.find({ field: { $lt: value } }) 查询user集合中age小于30的文档:
@Test public void findUser1() { // 创建查询条件 Criteria criteria = Criteria.where("age").lt(30); // 创建查询对象 Query query = new Query(criteria); // 执行查询 List users = mongoTemplate.find(query, User.class); users.forEach(System.out::println); // User(id=668f53342e9dde5bccea0096, name=Alice, age=25, email=alice@example.com, hobbies=[reading, writing, music]) // User(id=668f53342e9dde5bccea0098, name=Jane, age=25, email=Jane@qq.com, hobbies=[sports, music, cooking]) } 用于匹配字段值小于等于指定值的文档:
db.collection.find({ field: { $lte: value } }) 查询user集合中age小于等于30的文档:
@Test public void findUser2() { // 创建查询条件 Criteria criteria = Criteria.where("age").lte(30); // 创建查询对象 Query query = new Query(criteria); // 执行查询 List users = mongoTemplate.find(query, User.class); users.forEach(System.out::println); // User(id=668f53342e9dde5bccea0096, name=Alice, age=25, email=alice@example.com, hobbies=[reading, writing, music]) // User(id=668f53342e9dde5bccea0097, name=John, age=30, email=John@qq.com, hobbies=[reading, gaming, traveling]) // User(id=668f53342e9dde5bccea0098, name=Jane, age=25, email=Jane@qq.com, hobbies=[sports, music, cooking]) } 在指定值数组中,用于匹配字段值在指定值数组中的文档:
db.collection.find({ field: { $in: [value1, value2, ...] } }) 查询user集合中name等于Alice或Jone或Jane的文档:
db.user.find({ name: { $in: ["Alice", "John", "Jane"] } }) @Test public void findUser2() { // 创建查询条件 Criteria criteria = Criteria.where("name").in(Arrays.asList("Alice","John","Jane")); // 创建查询对象 Query query = new Query(criteria); // 执行查询 List users = mongoTemplate.find(query, User.class); users.forEach(System.out::println); // User(id=668f53342e9dde5bccea0096, name=Alice, age=25, email=alice@example.com, hobbies=[reading, writing, music]) // User(id=668f53342e9dde5bccea0097, name=John, age=30, email=John@qq.com, hobbies=[reading, gaming, traveling]) // User(id=668f53342e9dde5bccea0098, name=Jane, age=25, email=Jane@qq.com, hobbies=[sports, music, cooking]) } 不在指定值数组中,用于匹配字段值不在指定值数组中的文档:
db.collection.find({ field: { $nin: [value1, value2, ...] } }) 查询user集合中name不等于Alice、Jone、Jane的文档:
db.user.find({ name: { $nin: ["Alice", "John", "Jane"] } }) @Test public void findUser2() { // 创建查询条件 Criteria criteria = Criteria.where("name").nin(Arrays.asList("Alice","John","Jane")); // 创建查询对象 Query query = new Query(criteria); // 执行查询 List users = mongoTemplate.find(query, User.class); users.forEach(System.out::println); // User(id=668f53342e9dde5bccea0099, name=Mike, age=35, email=Mike@qq.com, hobbies=[reading, writing, painting]) } 逻辑操作符根据计算结果为 ture 或 false 的表达式来返回数据。MongoDB提供了丰富的逻辑查询操作符,用于在查询中进行逻辑运算和条件判断。以下是一些常用的逻辑查询操作符:
$and:用于同时满足多个条件的查询。
例如:db.collection.find({ $and: [ { condition1 }, { condition2 } ] })
$or:用于满足多个条件中的任意一个的查询。
例如:db.collection.find({ $or: [ { condition1 }, { condition2 } ] })
$not:用于否定一个条件的查询。
例如:db.collection.find({ field: { $not: { condition } } })
$nor:用于满足多个条件都不成立的查询。
例如:db.collection.find({ $nor: [ { condition1 }, { condition2 } ] })
这些逻辑查询操作符可以与其他查询条件结合使用,以实现更复杂的查询逻辑。
用于同时满足多个条件的查询。
db.collection.find({ $and: [ { condition1 }, { condition2 } ] }) 查询user集合中age大于等于18,并且name等于Alice的文档:
db.user.find({ $and: [ { age: { $gte: 18 } }, { name: "Alice" } ] }) @Test public void findUser1() { // 创建查询条件:首先创建了一个Criteria对象,并使用andOperator方法来添加多个条件 Criteria criteria = new Criteria(); criteria.andOperator( Criteria.where("age").gte(18), Criteria.where("name").is("Alice") ); // 创建查询对象 Query query = new Query(criteria); // 执行查询 List users = mongoTemplate.find(query, User.class); users.forEach(System.out::println); // User(id=668f53342e9dde5bccea0096, name=Alice, age=25, email=alice@example.com, hobbies=[reading, writing, music]) } @Test public void findUser1() { // 查询条件 Criteria criteria = Criteria.where("age").gte(18).and("name").is("Alice"); // 查询对象 Query query = new Query(); query.addCriteria(criteria); // 执行查询 List users = mongoTemplate.find(query, User.class); users.forEach(System.out::println); // User(id=668f53342e9dde5bccea0096, name=Alice, age=25, email=alice@example.com, hobbies=[reading, writing, music]) } 用于满足多个条件中的任意一个的查询。
db.collection.find({ $or: [ { condition1 }, { condition2 } ] }) 查询user集合中age小于30,或者name等于Alice的文档:
db.user.find({ $or: [ { age: { gt: 30 } }, { name: "Alice" } ] }) @Test public void findUser1() { // 创建查询条件 Criteria criteria = new Criteria(); // 首先创建了一个Criteria对象,并使用orOperator方法来添加多个条件 criteria.orOperator( Criteria.where("age").gt(30), Criteria.where("name").is("Alice") ); // 创建查询对象 Query query = new Query(criteria); // 执行查询 List users = mongoTemplate.find(query, User.class); users.forEach(System.out::println); // User(id=668f53342e9dde5bccea0096, name=Alice, age=25, email=alice@example.com, hobbies=[reading, writing, music]) // User(id=668f53342e9dde5bccea0099, name=Mike, age=35, email=Mike@qq.com, hobbies=[reading, writing, painting]) } 用于否定一个条件的查询。
db.collection.find({ field: { $not: { condition } } }) 查询user集合中age小于30的文档:
db.user.find({ age: { $not: { $gte: 30 } } }) @Test public void findUser1() { // 创建查询对象 Query query = new Query(Criteria.where("age").not().gte(30)); // 执行查询 List users = mongoTemplate.find(query, User.class); users.forEach(System.out::println); // User(id=668f53342e9dde5bccea0096, name=Alice, age=25, email=alice@example.com, hobbies=[reading, writing, music]) // User(id=668f53342e9dde5bccea0098, name=Jane, age=25, email=Jane@qq.com, hobbies=[sports, music, cooking]) } 用于满足多个条件都不成立的查询。
db.collection.find({ $nor: [ { condition1 }, { condition2 } ] }) 查询user集合中age小于30,并且name不等于Alice的文档
db.users.find({ $nor: [ { age: { $gte: 30 } }, { name: "Alice" } ] }) @Test public void findUser1() { Criteria criteria = new Criteria(); criteria.norOperator( Criteria.where("age").gte(30), Criteria.where("name").is("Alice") ); // 创建查询对象 Query query = new Query(criteria); // 执行查询 List users = mongoTemplate.find(query, User.class); users.forEach(System.out::println); // User(id=668f53342e9dde5bccea0098, name=Jane, age=25, email=Jane@qq.com, hobbies=[sports, music, cooking]) } 元素操作符根据字段是否存在或数据类型返回数据。
$exists:用于检查字段是否存在的查询。
例如:db.collection.find({ field: { $exists: true } })
$type:用于检查字段类型的查询。
例如:db.collection.find({ field: { $type: “string” } })
数据构造:向user集合中name等于Alice的文档新增一个字段
db.user.updateOne( { name: "Alice" }, { $set: {city: "ShangHai"} } ) @Test public void updateUser(){ // 构建查询条件 Criteria criteria = Criteria.where("name").is("Alice"); Query query = Query.query(criteria); // 构建更新操作 Update update = new Update(); update.set("city", "ShangHai"); // 执行更新操作 mongoTemplate.updateMulti(query, update, "user"); } 
用于检查字段是否存在的查询
db.collection.find({ field: { $exists: true } }) 查询user集合中city字段是否存在:
db.user.find({ city: { $exists: true } }) @Test public void findUser1() { // 查询条件 Criteria criteria = Criteria.where("city").exists(true); // 查询对象 Query query = new Query(criteria); // 执行查询 List users = mongoTemplate.find(query, User.class); users.forEach(System.out::println); // User(id=668f53342e9dde5bccea0096, name=Alice, age=25, email=alice@example.com, hobbies=[reading, writing, music]) } 用于检查字段类型的查询
db.collection.find({ field: { $type: "string" } }) $type 运算符接受的字段类型:
| 类型 | 数值 | 别名 | 注意 |
|---|---|---|---|
| 双精度 | 1 | “double” | |
| 字符串 | 2 | “string” | |
| 对象 | 3 | “object” | |
| 阵列 | 4 | “array” | |
| 二进制数据 | 5 | “binData” | |
| ObjectId | 7 | “objectId” | |
| 布尔 | 8 | “bool” | |
| Date | 9 | “date” | |
| null | 10 | “null” | |
| 正则表达式 | 11 | “regex” | |
| JavaScript | 13 | “javascript” | |
| 32 位整数 | 16 | “int” | |
| 时间戳 | 17 | “timestamp” | |
| 64 位整型 | 18 | “long” | |
| Decimal128 | 19 | “decimal” | |
| Min key | -1 | “minKey” | |
| Max key | 127 | “maxKey” |
查询user集合中name的字段类型是否为string:
db.user.find({ name: { $type: "string" } }) db.user.find( { name : { $type : 2 } } ) @Test public void findUser1() { // 查询条件 Criteria criteria = Criteria.where("name").type(2); // 查询对象 Query query = new Query(criteria); // 执行查询 List users = mongoTemplate.find(query, User.class); users.forEach(System.out::println); // User(id=668f53342e9dde5bccea0096, name=Alice, age=25, email=alice@example.com, hobbies=[reading, writing, music]) // User(id=668f53342e9dde5bccea0097, name=John, age=30, email=John@qq.com, hobbies=[reading, gaming, traveling]) // User(id=668f53342e9dde5bccea0098, name=Jane, age=25, email=Jane@qq.com, hobbies=[sports, music, cooking]) // User(id=668f53342e9dde5bccea0099, name=Mike, age=35, email=Mike@qq.com, hobbies=[reading, writing, painting]) } 数组操作符根据数组条件返回数据。MongoDB提供了多种数组查询操作符,用于在查询中对数组字段进行操作和匹配。以下是一些常用的数组查询操作符:
$elemMatch:用于在数组字段中匹配满足多个条件的元素的查询。
db.collection.find({ field: { $elemMatch: { condition1, condition2 } } })
$size:用于匹配数组字段的长度的查询。
db.collection.find({ field: { $size: 3 } })
$all:用于匹配数组字段中包含所有指定元素的查询。
db.collection.find({ field: { $all: [ element1, element2 ] } })
$in:用于匹配数组字段中包含指定元素的查询。例如:
db.collection.find({ field: { $in: [ element1, element2 ] } })
$nin:用于匹配数组字段中不包含指定元素的查询。例如:
db.collection.find({ field: { $nin: [ element1, element2 ] } })
$slice:用于返回数组字段的子集。例如:
db.collection.find({ field: { $slice: 5 } })
$addToSet:用于向数组字段添加唯一的元素。例如:
db.collection.updateOne({ _id: ObjectId(“…”) }, { $addToSet: { field: element } })
这些数组查询操作符可以与其他查询条件结合使用,以实现更复杂的查询逻辑。请注意,以上示例中的"collection"和"field"应替换为实际的集合名和字段名。
用于在数组字段中匹配满足多个条件的元素的查询。
db.collection.find({ arrayField: { $elemMatch: { condition1, condition2 } } }) 查询user集合中age大于等于30并且hobbies包含reading的文档:
db.user.find({ age: { $gte: 30 }, hobbies: { $elemMatch: { $eq: "reading" } } }) @Test public void findUser1() { // 查询条件 Criteria criteria = Criteria.where("age").gte(30).and("hobbies").elemMatch(Criteria.where("$eq").is("reading")); // 查询对象 Query query = new Query(criteria); // 执行查询 List users = mongoTemplate.find(query, User.class); users.forEach(System.out::println); // User(id=668f53342e9dde5bccea0097, name=John, age=30, email=John@qq.com, hobbies=[reading, gaming, traveling]) // User(id=668f53342e9dde5bccea0099, name=Mike, age=35, email=Mike@qq.com, hobbies=[reading, writing, painting]) } @Test public void findUser1() { // 查询条件 Criteria criteria = new Criteria(); criteria.andOperator( Criteria.where("age").gte(30), Criteria.where("hobbies").elemMatch(Criteria.where("$eq").is("reading")) ); // 查询对象 Query query = new Query(); query.addCriteria(criteria); // 执行查询 List users = mongoTemplate.find(query, User.class); users.forEach(System.out::println); // User(id=668f53342e9dde5bccea0097, name=John, age=30, email=John@qq.com, hobbies=[reading, gaming, traveling]) // User(id=668f53342e9dde5bccea0099, name=Mike, age=35, email=Mike@qq.com, hobbies=[reading, writing, painting]) } 查询user集合中hobbies数组包含reading的文档:
db.user.find( hobbies: { $elemMatch: { $eq: "reading" } } }) @Test public void findUser1() { // 查询条件 Criteria criteria = Criteria.where("hobbies").elemMatch(Criteria.where("$eq").is("reading")); // 查询对象 Query query = new Query(); query.addCriteria(criteria); // 执行查询 List users = mongoTemplate.find(query, User.class); users.forEach(System.out::println); // User(id=668f53342e9dde5bccea0096, name=Alice, age=25, email=alice@example.com, hobbies=[reading, writing, music]) //User(id=668f53342e9dde5bccea0097, name=John, age=30, email=John@qq.com, hobbies=[reading, gaming, traveling]) //User(id=668f53342e9dde5bccea0099, name=Mike, age=35, email=Mike@qq.com, hobbies=[reading, writing, painting]) } ① 查询survey集合中product为"xyz"且score大于或等于8 的文档:
db.survey.insertMany( [ { "_id": 1, "results": [ { "product": "abc", "score": 10 },{ "product": "xyz", "score": 5 } ] }, { "_id": 2, "results": [ { "product": "abc", "score": 8 },{ "product": "xyz", "score": 7 } ] }, { "_id": 3, "results": [ { "product": "abc", "score": 7 },{ "product": "xyz", "score": 8 } ] }, { "_id": 4, "results": [ { "product": "abc", "score": 7 },{ "product": "def", "score": 8 } ] }, { "_id": 5, "results": { "product": "xyz", "score": 9 } } ] ) 注意,_id 为 5 的文档不包含数组。
db.survey.find( { results: { $elemMatch: { product: "xyz", score: { $gte: 8 } } } } ) @Data @Document(collection = "survey") public class Survey { @Id private int _id; private List results; } @Data public class Result { private String product; private int score; } @Test public void findUser1() { // 查询条件 Query query = new Query(); query.addCriteria(Criteria.where("results").elemMatch( Criteria.where("product").is("xyz").and("score").gte(8) )); List surveyList = mongoTemplate.find(query, Survey.class, "survey"); surveyList.forEach(System.out::println); // Survey(_id=3, results=[Result(product=abc, score=7), Result(product=xyz, score=8)]) } ② 使用$elemMatch进行单一查询条件:
db.survey.find( { results: { $elemMatch: { product: "xyz" } } } ) 此查询会返回 results 中的任一 product 为 "xyz" 的文档。
③ 不使用$elemMatch进行单一查询条件:
db.survey.find( { "results.product": "xyz" } ) 此查询结果还包括 _id 为 5 的文档(不包含数组)
④ 查询student集合中所有数学成绩高于90分的学生:
db.student.insertMany( [ {"_id": 1, "name": "Alice", "grades": [ { "subject": "Math", "score": 90 }, { "subject": "English", "score": 85 }, { "subject": "Science", "score": 95 } ] }, { "_id": 2, "name": "Bob", "grades": [ { "subject": "Math", "score": 80 }, { "subject": "English", "score": 75 }, { "subject": "Science", "score": 85 } ] }, { "_id": 3, "name": "Charlie", "grades": [ { "subject": "Math", "score": 95 }, { "subject": "English", "score": 90 }, { "subject": "Science", "score": 92 } ] } ] ) db.students.find({ grades: { $elemMatch: { subject: "Math", score: { $gt: 90 } } } }) @Data @Document(collection = "student") public class Student { @Id private int _id; private String name; private List grades; } @Data public class Grade { private String subject; private int score; } @Test public void findUser1() { // 查询条件 Query query = new Query(); query.addCriteria(Criteria.where("grades").elemMatch( Criteria.where("subject").is("Math").and("score").gte(90) )); List studentList = mongoTemplate.find(query, Student.class, "student"); studentList.forEach(System.out::println); // Student(_id=1, name=Alice, grades=[Grade(subject=Math, score=90), Grade(subject=English, score=85), Grade(subject=Science, score=95)]) // Student(_id=3, name=Charlie, grades=[Grade(subject=Math, score=95), Grade(subject=English, score=90), Grade(subject=Science, score=92)]) } 用于匹配数组字段的长度的查询。
db.collection.find({ arrayField: { $size: 3 } }) 查询user集合中hobbies数组包含2个元素的所有文档:
db.user.insertMany([ { name: "Alice", age: 25, email: "alice@example.com", hobbies: ["writing"] }, { name: "John", age: 30, email: "John@qq.com", hobbies: ["reading", "gaming",] }, { name: "Jane", age: 25, email: "Jane@qq.com", hobbies: ["sports", "music"] }, { name: "Mike", age: 35, email: "Mike@qq.com", hobbies: ["reading", "writing", "painting", "cooking"] } ]); db.user.find( { hobbies: { $size: 2 } } ); @Test public void findUser1() { // 查询条件 Query query = new Query(); Criteria criteria = Criteria.where("hobbies").size(2); query.addCriteria(criteria); List users = mongoTemplate.find(query, User.class, "user"); users.forEach(System.out::println); // User(id=66906798197700004d003dcd, name=John, age=30, email=John@qq.com, hobbies=[reading, gaming]) //User(id=66906798197700004d003dce, name=Jane, age=25, email=Jane@qq.com, hobbies=[sports, music]) } 此查询返回 collection 中 field 为包含 2 个元素的数组的所有文档。
用于匹配数组字段中包含所有指定元素的查询。
db.collection.find({ field: { $all: [ element1, element2 ] } }) db.user.insertMany([ { name: "Alice", age: 25, email: "alice@example.com", hobbies: ["reading", "writing", "music"] }, { name: "John", age: 30, email: "John@qq.com", hobbies: ["reading", "gaming", "traveling"] }, { name: "Jane", age: 25, email: "Jane@qq.com", hobbies: ["sports", "music", "cooking"] }, { name: "Mike", age: 35, email: "Mike@qq.com", hobbies: ["reading", "writing", "painting"] } ]); 查询user集合中hobbies数组包含 “writing” 和 “music” 的文档:
db.user.find({ hobbies: { $all: [ "writing" , "music" ] } }) # 相当于 db.user.find({ $and: [ { hobbies: "writing" }, { hobbies: "music" } ] }) @Test public void findUser1() { // 查询条件 Query query = new Query(); Criteria criteria = Criteria.where("hobbies").all("music","writing"); query.addCriteria(criteria); List users = mongoTemplate.find(query, User.class, "user"); users.forEach(System.out::println); // User(id=6690693d197700004d003dd0, name=Alice, age=25, email=alice@example.com, hobbies=[reading, writing, music]) }