小编use*_*858的帖子

我正在尝试使用follwing命令将以下graphSon格式转换为图形实例

    graph.io(IoCore.graphson()).reader().create().readGraph(stream, graph);

但是在运行时将GRaphSON转换为下面给出的图形实例

{"id":0,
"label":"buyer",
"outE":
    {"email_is":
        [{"id":0,"inV":1,
            "properties":{"weight":1}
            }
        ]}
,"properties":
    {"buyer":
        [{
            "id":0,"value":"buyer0"
        }]
    ,"age":
        [{
            "id":1,"value":10}]
        }}              
{"id":1,
"label":"email",
"inE":
    { "email_is":
        [{"id":1,"outV":0,
        "properties":{"weight":1}}
        ]}

,"properties":
    {"email":
    [{"id":2,
    "value":"email0"
    }]
    }}

我收到以下错误

java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:497)
at org.codehaus.mojo.exec.ExecJavaMojo$1.run(ExecJavaMojo.java:293)
at java.lang.Thread.run(Thread.java:745)Caused by: java.lang.IllegalArgumentException: Invalid vertex provided: null
at com.google.common.base.Preconditions.checkArgument(Preconditions.java:145)
at com.thinkaurelius.titan.graphdb.vertices.AbstractVertex.addEdge(AbstractVertex.java:149)
at com.thinkaurelius.titan.graphdb.vertices.AbstractVertex.addEdge(AbstractVertex.java:23)
at org.apache.tinkerpop.gremlin.structure.io.graphson.GraphSONReader.lambda$null$57(GraphSONReader.java:114)
at java.util.Iterator.forEachRemaining(Iterator.java:116)
at org.apache.tinkerpop.gremlin.structure.io.graphson.GraphSONReader.lambda$readGraph$58(GraphSONReader.java:108)
at java.util.HashMap$EntrySet.forEach(HashMap.java:1035)
at org.apache.tinkerpop.gremlin.structure.io.graphson.GraphSONReader.readGraph(GraphSONReader.java:108)
at pluradj.titan.tinkerpop3.example.JavaExample2.main(JavaExample2.java:50)
... 6 more

任何人都可以告诉我一个更简单的方法来制作GRAPHSON文件,因为使用StringWriter和JSONWRiter类是一项非常繁琐的任务.

使用以下命令使用索引以获得更好的性能来查询titan db中的节点.

TitanManagement mgmt = graph.openManagement();
PropertyKey buyer = mgmt.makePropertyKey("buyer").dataType(String.class).cardinality(Cardinality.SINGLE).make();
TitanGraphIndex buyeri = mgmt.buildIndex("buyer", Vertex.class).addKey(buyer).buildCompositeIndex();
mgmt.setConsistency(buyeri, ConsistencyModifier.LOCK);
g.V().has("buyer","buyer", "buyer10").out("order_is").values("order").fill(list);     

使用titan 1.0.0,gremlin查询语言,在运行此查询时会抛出错误:

java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:497)
at org.codehaus.mojo.exec.ExecJavaMojo$1.run(ExecJavaMojo.java:293)
at java.lang.Thread.run(Thread.java:745)Caused by: com.thinkaurelius.titan.core.SchemaViolationException: Adding this property for key [~T$SchemaName] and value [rtbuyer] violates a uniqueness constraint [SystemIndex#~T$SchemaName]
at com.thinkaurelius.titan.graphdb.transaction.StandardTitanTx.addProperty(StandardTitanTx.java:780)
at com.thinkaurelius.titan.graphdb.transaction.StandardTitanTx.addProperty(StandardTitanTx.java:706)
at com.thinkaurelius.titan.graphdb.transaction.StandardTitanTx.makeSchemaVertex(StandardTitanTx.java:836)
at com.thinkaurelius.titan.graphdb.transaction.StandardTitanTx.makePropertyKey(StandardTitanTx.java:856)
at com.thinkaurelius.titan.graphdb.types.StandardPropertyKeyMaker.make(StandardPropertyKeyMaker.java:86)
at pluradj.titan.tinkerpop3.example.JavaExample2.main(JavaExample2.java:56)

更新如下所述@jason Plurad回答

我用过

 PropertyKey buyer = (!mgmt.containsPropertyKey("buyer")) ?
        mgmt.makePropertyKey("buyer").dataType(String.class).cardinality(Cardinality.SINGLE).make() :
        mgmt.getPropertyKey("buyer");
    TitanGraphIndex buyeri = mgmt.getGraphIndex("buyeri");
    if (buyeri …