我使用此代码从 mysql 数据库创建了公司节点
public class EnterCompaniesToNeo4j {
public static void main(String[] args) throws SQLException, ClassNotFoundException
{
ConnectionStrings c=new ConnectionStrings();
String CONN_STRING=c.getConnString();
String USERNAME=c.getUsername();
String PASSWORD=c.getPassword();
Connection conn=null;
PreparedStatement stmt=null;
int counter=0;
ResultSet rs=null;
Class.forName("com.mysql.jdbc.Driver");
conn=DriverManager.getConnection(CONN_STRING, USERNAME, PASSWORD);
GraphDatabaseService graphDB = new GraphDatabaseFactory().newEmbeddedDatabase("build\\web\\NEO4J databases\\db1");
Transaction tx = graphDB.beginTx();
Node n = null;
try
{
stmt=conn.prepareStatement("select * from companies where node_id IS NULL", ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_UPDATABLE);
// stmt.setString(1, "100641318");
rs=stmt.executeQuery();
while(rs.next())
{
// deo gde se kreira nod
counter=counter+1;
n = graphDB.createNode();
n.setProperty( "taxnumber", rs.getString("tax_number"));
n.setProperty( "name", rs.getString("name"));
n.setProperty( "email", rs.getString("email"));
long br;
br=n.getId();
rs.updateLong("node_id",br);
rs.updateRow();
//System.out.println(n.getProperty("taxnumber"));
//System.out.println(n.getId()+"");
System.out.println(rs.getString("name"));
}
tx.success();
}
catch ( Exception e )
{
tx.failure();
}
finally
{
tx.finish();
stmt.close();
rs.close();
conn.close();
}
//ExecutionEngine engine = new ExecutionEngine( graphDB );
//ExecutionResult result = engine.execute( "start n=node(2) return n, n.taxnumber,n.name" );//vracanje noda 1
//ExecutionResult result = engine.execute( "START n = node(*) DELETE n" ); //brisanje svih nodova
//System.out.println(result.toString());
System.out.println(""+counter);
graphDB.shutdown();
}
}
现在我想让用户在登录后插入关系，我从 servlet 这样做
public class InputDebtDataToNeo4j extends HttpServlet {
GraphDatabaseService graphDB = new GraphDatabaseFactory().newEmbeddedDatabase("build\\web\\NEO4J databases\\db1");
Transaction tx = graphDB.beginTx();
protected void processRequest(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=UTF-8");
PrintWriter out = response.getWriter();
ArrayList<InputData> l111 = new ArrayList<InputData>();
ArrayList<InputData> l222 = new ArrayList<InputData>();
HttpSession session=request.getSession(true);
l111= (ArrayList<InputData>) session.getAttribute("hasdata");
l222=(ArrayList<InputData>) session.getAttribute("hasnotdata");
//put ka Neo4j bazi
long mynodenumber;
mynodenumber = Long.parseLong(session.getAttribute("node_id").toString());
try {
for (InputData element : l111)
{
ExecutionEngine engine = new ExecutionEngine( graphDB );
ExecutionResult result = engine.execute( "START a=node("+mynodenumber+"), b=node("+element.getNodeidnumber()+") CREATE a-[r:OWE{amount:"+element.getDebtamount()+"}]->b RETURN r" );//vracanje noda 1
out.println("Relacija "+result.toString()+"</br>");
out.println("Taks broj "+element.getTaxnumberdata()+"</br>");
out.println("Node Broj "+element.getNodeidnumber()+"</br>");
out.println("Iznos duga "+String.valueOf(element.getDebtamount())+"</br>");
out.println("Moj node broj "+mynodenumber+"</br>");
}
//response.sendRedirect("DebtSolutions.jsp");
tx.success();
}
catch(Exception e )
{
tx.failure();
out.println(e.toString());
}
finally {
tx.finish();
graphDB.shutdown();
out.close();
}
}
结果我收到了这个错误信息
type Exception report
message Error instantiating servlet class servlets.InputDebtDataToNeo4j
description The server encountered an internal error that prevented it from fulfilling this request.
exception
javax.servlet.ServletException: Error instantiating servlet class servlets.InputDebtDataToNeo4j
org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:947)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1009)
org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoint.java:1852)
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
java.lang.Thread.run(Thread.java:722)
root cause
java.lang.IllegalStateException: Database locked.
org.neo4j.kernel.InternalAbstractGraphDatabase.create(InternalAbstractGraphDatabase.java:289)
org.neo4j.kernel.InternalAbstractGraphDatabase.run(InternalAbstractGraphDatabase.java:227)
org.neo4j.kernel.EmbeddedGraphDatabase.<init>(EmbeddedGraphDatabase.java:79)
org.neo4j.graphdb.factory.GraphDatabaseFactory$1.newDatabase(GraphDatabaseFactory.java:70)
org.neo4j.graphdb.factory.GraphDatabaseBuilder.newGraphDatabase(GraphDatabaseBuilder.java:205)
org.neo4j.graphdb.factory.GraphDatabaseFactory.newEmbeddedDatabase(GraphDatabaseFactory.java:56)
servlets.InputDebtDataToNeo4j.<init>(InputDebtDataToNeo4j.java:30)
sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
java.lang.reflect.Constructor.newInstance(Constructor.java:525)
java.lang.Class.newInstance0(Class.java:372)
java.lang.Class.newInstance(Class.java:325)
org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:947)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1009)
org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoint.java:1852)
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
java.lang.Thread.run(Thread.java:722)
我应该在我的 servlet 中做什么才能使其工作...