希望这对您有用，并且您可以从中获得帮助。我执行了数据库操作（插入、删除、更新、获取、getall）并使用 Person 对象在 MongoDB 中使用 java 进行操作以进行演示。
- 数据库连接类
连接.java
package test;
import org.bson.codecs.configuration.CodecRegistry;
import org.bson.codecs.pojo.PojoCodecProvider;
import static org.bson.codecs.configuration.CodecRegistries.fromProviders;
import static org.bson.codecs.configuration.CodecRegistries.fromRegistries;
import com.mongodb.MongoClient;
import com.mongodb.MongoClientOptions;
import com.mongodb.client.MongoDatabase;
public class Connection {
public MongoClient mongo;
private String db;
public MongoDatabase database;
private static Connection instance;
private Connection() {
db = "chatsystem";
CodecRegistry pojoCodecRegistry = fromRegistries(MongoClient.getDefaultCodecRegistry(),
fromProviders(PojoCodecProvider.builder().automatic(true).build()));
mongo = new MongoClient("localhost", MongoClientOptions.builder().codecRegistry(pojoCodecRegistry).build());
database = mongo.getDatabase(db);
}
public static Connection getInstance() {
if (instance == null) {
instance = new Connection();
return instance;
} else {
return instance;
}
}
}
- 模型类
人.java
package test;
import org.bson.types.ObjectId;
public class Person {
public Person() {
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public String getFname() {
return fname;
}
public void setFname(String fname) {
this.fname = fname;
}
public String getLname() {
return lname;
}
public void setLname(String lname) {
this.lname = lname;
}
private ObjectId id;
public Person(String username, String email, String password, String fname, String lname) {
super();
this.username = username;
this.email = email;
this.password = password;
this.fname = fname;
this.lname = lname;
}
public ObjectId getId() {
return id;
}
public void setId(ObjectId id) {
this.id = id;
}
private String username;
private String email;
private String password;
private String fname;
private String lname;
}
- 主班
测试.java
package test;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import static com.mongodb.client.model.Filters.*;
import com.mongodb.client.FindIterable;
import com.mongodb.client.MongoCollection;
public class test {
private MongoCollection<Person> person;
Connection conn;
public void getCollection() {
conn = Connection.getInstance();
person = conn.database.getCollection("person", Person.class);
}
public static void main(String[] args) throws Exception {
test t = new test();
t.getCollection();
Person p = new Person();
p.setEmail("test@test.com");
p.setFname("ftest");
p.setLname("ltest");
p.setPassword("testtest");
p.setUsername("test123");
// insert person type objects in database
t.insertPerson(p);
// get all persons from database
List<Person> pp = t.getAllPersons();
Person pt = pp.get(0);
System.out.println(pt.getEmail());
System.out.println(pt.getId());
// get one person from database by username filter
// pass username of person in method argument
Person ph = t.getOnePerson("test123");
System.out.println(ph.getEmail());
System.out.println(ph.getId());
// update/edit person by username filter
// pass username of person in method argument
t.updatePerson("test123");
// delete person by username filter
// pass username of person in method argument
t.removePerson("updatetest123");
}
public void insertPerson(Person p) {
person.insertOne(p);
}
public List<Person> getAllPersons() {
FindIterable<Person> iterable = person.find();
Iterator it = iterable.iterator();
List<Person> allPersons = new ArrayList<>();
while (it.hasNext()) {
Person per = (Person) it.next();
allPersons.add(per);
}
return allPersons;
}
public Person getOnePerson(String username) {
return person.find(eq("username", username)).first();
}
public void updatePerson(String username) {
Person p = new Person();
p.setEmail("update@test.com");
p.setFname("updateftest");
p.setLname("updateltest");
p.setPassword("updatetesttest");
p.setUsername("updatetest123");
person.replaceOne(eq("username", username), p);
}
public void removePerson(String username) {
person.deleteOne(eq("username", username));
}
}