Question

解释一下是编译时出现错误？我实在找不出是什么错误了，谁能帮帮我。

at com.tree.ArticleTree.main(ArticleTree.java:12)
java.sql.SQLException: Operation not allowed after ResultSet closed
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1074)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:988)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:974)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:919)
at com.mysql.jdbc.ResultSetImpl.checkClosed(ResultSetImpl.java:803)
at com.mysql.jdbc.ResultSetImpl.next(ResultSetImpl.java:6985)
at com.tree.ArticleTree.show(ArticleTree.java:23)
at com.tree.ArticleTree.main(ArticleTree.java:12)
请看上面源码

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Answer 1

貌似你关闭rs之后，也就是rs.close()之后不用在声明rs=null了,你把这儿的rs=null,stmt=null,conn=null删了，试试，剩下的两个同理，，，