java Neo4j类型不匹配
我试图在eclipse中编写一个连接到neo4j的JDBC代码。我可以让它连接到数据库,但我在运行查询时遇到了问题。我已经导入了Neo4J驱动程序jar,以及所需的大多数驱动程序导入。尽管如此,我仍然在两个地方遇到了错误:
PreparedStatement statement = conn.prepareStatement(cypher);
给我一个错误:
这条线上有多个标记
- The method prepareStatement(String) is undefined for the type Connection
- Type mismatch: cannot convert from java.sql.PreparedStatement to org.neo4j.jdbc.PreparedStatement
我不明白为什么是java。之所以包含sql,是因为我没有将其导入此类
我的另一个错误在第行:
连接连接=驱动器管理器。getConnection(“jdbc:neo4j:bolt://localhost“,”,”)
我在这里遇到的错误是:无法解决DriverManager
我的代码(未完成)如下。我的问题是,我应该做些什么来帮助解决这些错误
private static void runCypher(Connection conn, String cypher) {
PreparedStatement statement = conn.prepareStatement(cypher);
}
public static void main (String[] args) {
try {
Connection conn = DriverManager.getConnection("jdbc:neo4j:bolt://localhost", "", "");
String cypher = "";
String option = "";
String instr = "Enter a: Show distinct sids and snames of suppliers who supply a red part or a green part." + "\n"
+ "Enter b: Show distinct sids and snames of suppliers who supply a red part and a green part."
+ "\n" + "Enter c: Insert a new supplier." + "\n"
+ "Enter d: Quit Program.";
while (true) {
option = JOptionPane.showInputDialog(instr);
if (option.equals("a")) {
cypher = "match (s:Suppliers)-[:supplies]->(p:Parts) where p.color = ‘red’ or p.color = ‘green’ return distinct s.sid, s.sname;";
runCypher(conn, cypher);
} else if (option.equalsIgnoreCase("b")) {
cypher = "match (p1:Parts)<-[:supplies]-(s:Suppliers)-[:supplies]->(p2:Parts) where p1.color = ‘red’ and p2.color = ‘green’ return distinct s.sid, s.sname;";
runCypher(conn, cypher);
} else if (option.equals("c")) {
cypher = "match (p:Parts)<-[sup:supplies]-(s:Suppliers) return p.pid, p.pname, max(toInteger(sup.cost)) order by p.pid;";
runCypher(conn, cypher);
} else {
break;
}
}}catch(Exception e ) {
System.out.println("Program terminates due to errors");
e.printStackTrace(); // for debugging
}
}
我的进口:
import org.neo4j.driver.internal.spi.Connection;
import org.neo4j.driver.v1.StatementResult;
import org.neo4j.jdbc.PreparedStatement;
import org.neo4j.jdbc.ResultSet;
import org.neo4j.jdbc.ResultSetMetaData;
# 1 楼答案
错误消息
DriverManager cannot be resolved
表示编译器不知道该类/字段/。。。因此,它可能缺少相应的导入:错误
The method prepareStatement(String) is undefined for the type Connection
意味着找不到该方法,因为您正在导入并使用错误的Connection
类。我不记得曾经使用过驱动程序JAR中的类,尽管驱动程序本身需要加载(不久前…)。基于给定给DriverManager
的URL,Java使用了正确的类。您只需要使用java.sql
包中的类这里有一个非常简单的例子:
实际上,使用never Java,您只需要
DriverManager
,编译器在这方面做得很好: