MongoDB的3.x版本java驱动相对2.x做了全新的设计，类库和使用方法上有很大区别。例如用Document替换BasicDBObject、通过Builders类构建Bson替代直接输入$命令等，本文整理了基于3.2版本的常用增删改查操作的使用方法。为了避免冗长的篇幅，分为增删改、查询、聚合、地理索引等几部分。
创建一个maven项目，添加依赖
<dependencies>
<dependency>
<groupId>org.mongodb</groupId>
<artifactId>mongodb-driver</artifactId>
<version>3.2.2</version>
</dependency>
</dependencies>http://central.maven.org/maven2/org/mongodb/mongo-java-driver/3.2.2/mongo-java-driver-3.2.2.jar
创建基础代码测试连接
public class CudExamples {
public static void main(String[] args) throws ParseException {
//根据实际环境修改ip和端口
MongoClient mongoClient = new MongoClient("localhost", 27017);
MongoDatabase database = mongoClient.getDatabase("lesson");
MongoCollection<Document> mc = database.getCollection("language");
//插入一个文档
mc.insertOne(new Document("oop", "java"));
System.out.println(mc.findOneAndDelete(new Document("oop", "java")));
mongoClient.close();
}
}改造CudExamples类以方便演示每种操作对集合的影响
public class CudExamples {
public static void main(String[] args) throws ParseException {
MongoClient mongoClient = new MongoClient("localhost", 27017);
MongoDatabase database = mongoClient.getDatabase("lesson");
CudExamples client = new CudExamples(database);
client.show();
mongoClient.close();
}
private MongoDatabase database;
public CudExamples(MongoDatabase database) {
this.database = database;
}
public void show() {
MongoCollection<Document> mc = database.getCollection("language");
//每次执行前清空集合以方便重复运行
mc.drop();
mc.insertOne(new Document("oop", "java"));
printCollection("insert java", mc);
}
//打印查询的结果集
public void printCollection(String doing, MongoCollection<Document> mc) {
System.out.println(doing);
FindIterable<Document> iterable = mc.find();
iterable.forEach(new Block<Document>() {
public void apply(final Document document) {
System.out.println(document);
}
});
System.out.println("------------------------------------------------------");
System.out.println();
}
}如上面代码所示，把所有的操作集中在show()方法中演示，并且在执行后打印集合以观察对集合的影响。下面来填充show()方法，注意需要静态导入Updates.*
import static com.mongodb.client.model.Updates.*;
mc.insertOne(new Document("oop", "java"));
printCollection("insert java", mc);
//插入一个包含两个字段的文档
Document doc = new Document("oop", "csharp").append("copyright", "microsoft");
mc.insertOne(doc);
printCollection("insert csharp", mc);
//查找并修改一个文档
mc.findOneAndReplace(new Document("oop", "java"), new Document("oop", "java").append("copyright", "oracle"));
printCollection("findAndReplace java", mc);
//删除一个文档
mc.deleteOne(new Document("oop", "java"));
printCollection("delete java", mc);
//删除全部文档
mc.deleteMany(new Document());
printCollection("delete all", mc);
//重新插入测试文档
mc.insertOne(new Document("oop", "java").append("copyright", "oracle"));
mc.insertOne(new Document("oop", "csharp").append("copyright", "microsoft"));
printCollection("insert java,csharp and swift", mc);
//$set 文档中存在指定字段则修改,没有则添加
mc.updateMany(new Document(), set("rank", 100));
printCollection("$set all rank 100", mc);
//$unset 文档中存在指定字段则删除该字段
mc.updateOne(new Document("oop", "csharp"), unset("rank"));
printCollection("unset csharp rank", mc);
//$inc 文档中存在指定字段则相加,没有则添加
mc.updateOne(new Document("oop", "csharp"), inc("rank", 30));
printCollection("$inc csharp rank 30", mc);
mc.updateOne(new Document("oop", "csharp"), inc("rank", 31));
printCollection("$inc csharp rank 31", mc);
//$setOnInsert 在更新时指定upsert=true并实际触发了插入操作时生效
mc.updateOne(new Document("oop", "swift").append("copyright", "apple"), setOnInsert("rank", 100), new UpdateOptions().upsert(true));
printCollection("$setOnInsert rank 100 for swift", mc);
//$mul 相乘
mc.updateOne(new Document("oop", "java"), mul("rank", 0.2));
printCollection("$mul java rank: 0.2", mc);
//$rename 重命名
mc.updateMany(new Document(), rename("rank", "ranks"));
printCollection("$rename all rank to ranks", mc);
//$min 取当前值和指定值之间比较小的
mc.updateMany(new Document(), min("ranks", 50));
printCollection("$min all ranks: 50", mc);
//$max 取当前值和指定值之间比较大的
mc.updateMany(new Document(), max("ranks", 40));
printCollection("$max all ranks: 40", mc);
//$currentDate
mc.updateMany(new Document("oop", "java"), currentDate("add"));
printCollection("$currentDate java", mc);
//$currentTimestamp
mc.updateMany(new Document("oop", "java"), currentTimestamp("lastModified"));
printCollection("$currentTimestamp java", mc);
//$addToSet 添加一个元素到不重复集合
mc.updateMany(new Document("oop", "java"), addToSet("keywords", "for"));
mc.updateMany(new Document("oop", "java"), addToSet("keywords", "for"));
printCollection("$addToSet java keywords: for", mc);
//$addEachToSet 添加一组元素到不重复集合
mc.updateMany(new Document("oop", "java"), addEachToSet("keywords", Arrays.asList("while", "true", "do", "new", "override")));
mc.updateMany(new Document("oop", "java"), addEachToSet("keywords", Arrays.asList("while", "true", "do", "new", "override")));
printCollection("$addEachToSet java keywords: while,true,do,new,override", mc);
//$popFirst 删除第一个元素
mc.updateMany(new Document("oop", "java"), popFirst("keywords"));
printCollection("$popFirst java keywords", mc);
//$popLast 删除最后一个元素
mc.updateMany(new Document("oop", "java"), popLast("keywords"));
printCollection("$popLast java keywords", mc);
//$pull 删除指定元素
mc.updateMany(new Document("oop", "java"), pull("keywords", "new"));
printCollection("$pull java keywords: new", mc);
//$pullByFilter 根据Filters删除
mc.updateMany(new Document("oop", "java"), pullByFilter(Filters.gte("keywords", "true")));
printCollection("$pullByFilter java keywords: true", mc);
//$pullAll 删除一组元素
mc.updateMany(new Document("oop", "java"), pullAll("keywords", Arrays.asList("while", "true", "do", "new", "override")));
printCollection("$pullAll java keywords", mc);
//$push 添加一个元素到可重复集合
mc.updateMany(new Document("oop", "java"), push("scores", 89));
printCollection("$push java scores: 89", mc);
//$pushEach 添加一组元素到可重复集合
mc.updateMany(new Document("oop", "java"), pushEach("scores", Arrays.asList(89, 90, 92)));
printCollection("$pushEach java scores: 89,90,92", mc);
//在集合的指定位置插入一组元素
mc.updateMany(new Document("oop", "java"), pushEach("scores", Arrays.asList(11, 12, 13), new PushOptions().position(0)));
printCollection("$pushEach java scores: 11,12,13 at position 0", mc);
//在集合的指定位置插入一组元素并倒序排列
mc.updateMany(new Document("oop", "java"), pushEach("scores", Arrays.asList(40, 41), new PushOptions().sort(-1)));
printCollection("$pushEach java scores: 40,41 and sort(-1)", mc);
//在集合的指定位置插入一组元素, 倒序排列后保留前3个
mc.updateMany(new Document("oop", "java"), pushEach("scores", Arrays.asList(60, 61), new PushOptions().sort(-1).slice(3)));
printCollection("$pushEach java scores: 60,61 and sort(-1) and slice(3)", mc);
//插入一组内嵌文档
Bson bson = pushEach("experts",
Arrays.asList(new Document("first", "Rod").append("last", "Johnson"),
new Document("first", "Doug").append("last", "Cutting")));
mc.updateOne(new Document("oop", "java"), bson);
printCollection("$pushEach", mc);
//combine 组合Bson
bson = combine(set("author", "James Gosling"), set("version", "8.0"));
mc.updateOne(new Document("oop", "java"), bson);
printCollection("$combine", mc);