在java中執行密碼查詢異常

Question

我想從使用事務處理程序的neo4j DB中檢索數據。我已經添加了以下jar文件

import java.io.File; 
import java.io.IOException; 
import java.util.Iterator; 
import java.util.List; 
import java.util.Map; 
import java.util.Map.Entry; 
import java.util.HashMap; 
import org.neo4j.cypher.javacompat.ExecutionEngine; 
import org.neo4j.cypher.javacompat.ExecutionResult; 
import org.neo4j.graphdb.GraphDatabaseService; 
import org.neo4j.graphdb.Node; 
import org.neo4j.graphdb.Transaction; 
import org.neo4j.graphdb.factory.GraphDatabaseFactory; 
import org.neo4j.helpers.collection.IteratorUtil; 
import org.neo4j.kernel.EmbeddedGraphDatabase; 
import org.neo4j.kernel.impl.util.FileUtils; 

public class SampleNeo4j { 
    private static final String DB_PATH = "C:\\Users\\amritak\\neo4jTest"; 
    ExecutionResult result; 
    ExecutionResult resultString; 
    String columnsString; 
    String nodeResult; 
    String nodeResultAge; 
    String rows = ""; 
    CypherParser parser = new CypherParser(); 
    Query query; 

    void run() { 

     GraphDatabaseService db = new EmbeddedGraphDatabase(DB_PATH); 
     db.registerTransactionEventHandler(new WarehouseTransactionEventHandler()); 
     query = parser.parse("start n=node(*) return n"); 
     ExecutionEngine engine = new ExecutionEngine(db); 
     result = engine.execute(query); 
     System.out.println("col string"); 
     System.out.println(result); 
     resultString = engine.execute(query); 
     System.out.println("With Out Dump : "+resultString); 
     List<String> columns = resultString.columns(); 
     System.out.println(columns); 

     Iterator<Node> n_column = resultString.columnAs("n"); 
     for (Node nodes : IteratorUtil.asIterable(n_column)) { 
      // note: we're grabbing the name property from the node, 
      // not from the n.name in this case. 
      nodeResult = nodes + ": " + nodes.getProperty("name"); 
      nodeResultAge = nodes + ": " + nodes.getProperty("age"); 
      System.out.println(nodeResult); 
      System.out.println(nodeResultAge); 
     } 

     for (Map<String, Object> row : resultString) { 
      for (Entry<String, Object> column : row.entrySet()) { 
       rows += column.getKey() + ": " + column.getValue() + "; "; 
      } 
      rows += "\n"; 
     } 
     System.out.println(rows); 
     db.shutdown(); 
    } 

    public static void main(String args[]) { 
     SampleNeo4j javaQuery = new SampleNeo4j(); 
     javaQuery.run();  
    } 
} 

雖然我經常收到同樣的錯誤

Exception in thread "main" java.lang.NoSuchMethodError: scala.Predef$.augmentString(Ljava/lang/String;)Lscala/collection/immutable/StringOps; 
    at org.neo4j.cypher.parser.CypherParser.parse(CypherParser.scala:62) 
    at com.graphaware.tx.event.batch.api.SampleNeo4j.run(SampleNeo4j.java:45) 
    at com.graphaware.tx.event.batch.api.SampleNeo4j.main(SampleNeo4j.java:81) 

這表明此錯誤是

query = parser.parse("start n=node(*) return n"); 

u能告訴我該怎麼做線刪除此錯誤？

Answer 1

public static void main(final String[] args) { 
    GraphDatabaseService graphDb = new GraphDatabaseFactory().newEmbeddedDatabase(DB_PATH); 

    ExecutionEngine e=new ExecutionEngine(graphDb); 
    ExecutionResult rs=e.execute("match n return n limit 25"); 
    System.out.println(rs.columns().size()); 

    Iterator<Map<String, Object>> i= rs.iterator(); 

    Iterator<Node> n_column = rs.columnAs("n"); 

    while(n_column.hasNext()) { 
     System.out.println(n_column.next().getProperty("name")); 
    } 
} 

此代碼適用於我。這裏DB_Path是一個包含graphdb文件位置的字符串。