查询参数

以下示例说明了如何从 Java 执行 Cypher 查询时使用参数。

有关参数的更多信息，请参阅 Neo4j Cypher 手册.

节点 ID

Map<String,Object> params = new HashMap<>();
params.put( "id", 0 );

String query =
    "MATCH (n)" + "\n" +
    "WHERE id(n) = $id" + "\n" +
    "RETURN n.name";

Result result = transaction.execute( query, params );

节点对象

Map<String,Object> params = new HashMap<>();
params.put( "node", bobNode );

String query =
    "MATCH (n:Person)" + "\n" +
    "WHERE n = $node" + "\n" +
    "RETURN n.name";

Result result = transaction.execute( query, params );

多个节点 ID

Map<String,Object> params = new HashMap<>();
params.put( "ids", asList( 0, 1, 2 ) );

String query =
    "MATCH (n)" + "\n" +
    "WHERE id(n) IN $ids" + "\n" +
    "RETURN n.name";

Result result = transaction.execute( query, params );

字符串文字

Map<String,Object> params = new HashMap<>();
params.put( "name", "Johan" );

String query =
    "MATCH (n:Person)" + "\n" +
    "WHERE n.name = $name" + "\n" +
    "RETURN n";

Result result = transaction.execute( query, params );

用于 SKIP 和 LIMIT 的数字参数

Map<String,Object> params = new HashMap<>();
params.put( "s", 1 );
params.put( "l", 1 );

String query =
    "MATCH (n:Person)" + "\n" +
    "RETURN n.name" + "\n" +
    "SKIP $s" + "\n" +
    "LIMIT $l";

Result result = transaction.execute( query, params );

正则表达式

Map<String,Object> params = new HashMap<>();
params.put( "regex", ".*h.*" );

String query =
    "MATCH (n:Person)" + "\n" +
    "WHERE n.name =~ $regex" + "\n" +
    "RETURN n.name";

Result result = transaction.execute( query, params );

创建具有属性的节点

Map<String,Object> props = new HashMap<>();
props.put( "name", "Andy" );
props.put( "position", "Developer" );

Map<String,Object> params = new HashMap<>();
params.put( "props", props );

String query = "CREATE ($props)";

transaction.execute( query, params );

创建具有属性的多个节点

Map<String,Object> n1 = new HashMap<>();
n1.put( "name", "Andy" );
n1.put( "position", "Developer" );
n1.put( "awesome", true );

Map<String,Object> n2 = new HashMap<>();
n2.put( "name", "Michael" );
n2.put( "position", "Developer" );
n2.put( "children", 3 );

Map<String,Object> params = new HashMap<>();
List<Map<String,Object>> maps = asList( n1, n2 );
params.put( "props", maps );

String query =
    "UNWIND $props AS properties" + "\n" +
    "CREATE (n:Person)" + "\n" +
    "SET n = properties" + "\n" +
    "RETURN n";

Result result = transaction.execute( query, params );

设置节点上的所有属性

Map<String, Object> n1 = new HashMap<>();
n1.put( "name", "Andy" );
n1.put( "position", "Developer" );

Map<String, Object> params = new HashMap<>();
params.put( "props", n1 );

String query =
    "MATCH (n:Person)" + "\n" +
    "WHERE n.name = 'Michaela'" + "\n" +
    "SET n = $props";

transaction.execute( query, params );