将MySQL一张表的数据迁移到MongoDB数据库的Java代码示例

Java代码:

package com.zifeiy.snowflake.handle.etl.mongodb;

import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List; import org.bson.Document; import com.mongodb.MongoClient;
import com.mongodb.client.FindIterable;
import com.mongodb.client.MongoCollection;
import com.mongodb.client.MongoCursor;
import com.mongodb.client.MongoDatabase;
import com.zifeiy.snowflake.handle.etl.dbconnection.DatabaseConnectionFactory; /*
* 这个类用于将MySQL中的一张表的数据原模原样地传输到MongoDB中
*/
public class MySQLtoMongoDBDataTransfer { public boolean transfer(String databaseName, String tableName) {
try {
// mysql connection
Connection connection = DatabaseConnectionFactory.createConnection(databaseName);
Statement statement = connection.createStatement();
ResultSet resultSet = statement.executeQuery("select * from " + tableName);
// mongo connect
MongoClient mongoClient = new MongoClient();
MongoDatabase mongoDatabase = mongoClient.getDatabase(databaseName);
MongoCollection<Document> collection = mongoDatabase.getCollection(tableName);
// 首先清空collection
FindIterable<Document> deleteDocuments = collection.find();
MongoCursor<Document> deleteIterator = deleteDocuments.iterator();
while (deleteIterator.hasNext()) {
collection.deleteOne(deleteIterator.next());
}
// begin transfer
int columnCount = -1, count = 0;
List<Document> documents = new ArrayList<Document>();
while (resultSet.next()) {
if (columnCount == -1) {
columnCount = resultSet.getMetaData().getColumnCount();
}
Document document = new Document();
for (int i = 1; i <= columnCount; i ++) {
String columnName = resultSet.getMetaData().getColumnName(i);
Object value = resultSet.getObject(i);
document.append(columnName, value);
}
documents.add(document);
count ++;
if (count % 1000 == 0) { // 每1000条数据执行一次插入
collection.insertMany(documents);
documents = new ArrayList<Document>();
System.out.println("transfer " + count + " lines from mysql to mongodb ...");
}
}
System.out.println("total transfer " + count + " lines!"); DatabaseConnectionFactory.closeConnection(connection);
return true;
} catch (Exception e) {
e.printStackTrace();
return false;
}
} // main for test
public static void main(String[] args) {
new MySQLtoMongoDBDataTransfer().transfer("naturaldb", "NAT_IMBS_T_SIGN");
}
}

其中:

  • databaseName对应MySQL数据库的database,对应MongoDB的database;

    tableName`对应MySQL数据库的表,对应MongoDB的collection。
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