Java 11 中使用 JDBC 4 访问 H2 数据库时,通过预准备语句运行简单查询失败。
运行此行时:
try ( ResultSet rs = pstmt.executeQuery( sql ) ; ) {
。我收到此错误:
org.h2.jdbc.JdbcSQLException:预准备语句不允许使用此方法;请改用常规语句。[90130-197]
我尝试使用 H2 错误分析器,但没有帮助。
下面是单个.java文件中的完整示例应用。您可以复制粘贴并自行运行。
package com.basilbourque.example.work.basil.example.h2.pstmt_query;
import org.h2.jdbcx.JdbcDataSource;
import java.sql.*;
import java.util.ArrayList;
import java.util.List;
import java.util.UUID;
public class App {
public static void main ( String[] args ) {
App app = new App();
app.doIt();
}
private void doIt ( ) {
// Create database.
try {
Class.forName( "org.h2.Driver" );
} catch ( ClassNotFoundException e ) {
e.printStackTrace();
}
JdbcDataSource dataSource = new JdbcDataSource();
dataSource.setURL( "jdbc:h2:mem:pstmt_query_example_db;DB_CLOSE_DELAY=-1" ); // Set `DB_CLOSE_DELAY` to `-1` to keep in-memory database in existence after connection closes.
dataSource.setUser( "scott" );
dataSource.setPassword( "tiger" );
// Create table.
try (
Connection conn = dataSource.getConnection() ;
Statement stmt = conn.createStatement() ;
) {
String sql = "CREATE TABLE person_ ( n" +
" pkey_ UUID NOT NULL DEFAULT RANDOM_UUID() PRIMARY KEY , n" +
" name_ VARCHAR NOT NULL n" +
");";
System.out.println( sql );
stmt.execute( sql );
} catch ( SQLException e ) {
e.printStackTrace();
}
// Query table.
List < UUID > list = new ArrayList <>();
String sql = "SELECT * FROM person_ WHERE name_ = ? ;";
try (
Connection conn = dataSource.getConnection() ;
PreparedStatement pstmt = conn.prepareStatement( sql ) ;
) {
String name = "Wendy Melvoin";
pstmt.setString( 1 , name );
try ( ResultSet rs = pstmt.executeQuery( sql ) ; ) { // org.h2.jdbc.JdbcSQLException: This method is not allowed for a prepared statement; use a regular statement instead. [90130-197]
while ( rs.next() ) {
UUID pkey = rs.getObject( "pkey_" , UUID.class );
list.add( pkey );
}
}
} catch ( SQLException e ) {
e.printStackTrace();
}
}
}
报告异常:
org.h2.jdbc.JdbcSQLException: This method is not allowed for a prepared statement; use a regular statement instead. [90130-197]
at org.h2.message.DbException.getJdbcSQLException(DbException.java:357)
at org.h2.message.DbException.get(DbException.java:179)
at org.h2.message.DbException.get(DbException.java:155)
at org.h2.message.DbException.get(DbException.java:144)
at org.h2.jdbc.JdbcPreparedStatement.executeQuery(JdbcPreparedStatement.java:302)
at com.basilbourque.example.work.basil.example.h2.pstmt_query.App.doIt(App.java:53)
at com.basilbourque.example.work.basil.example.h2.pstmt_query.App.main(App.java:13)
传递 SQL 字符串两次
在PreparedStatement
,你永远不会将SQL字符串传递给executeQuery
方法。你这样做是在毫无准备的Statement
,但不是PreparedStatement
。请注意 JavaDoc for PreparedStatement::executeQuery
如何不进行任何争论。
所以你的行:
try ( ResultSet rs = pstmt.executeQuery( sql ) ; ) {
。应该是:
try ( ResultSet rs = pstmt.executeQuery() ; ) {
当您准备语句时,您已经在该行上方传递了名为 sql
的 SQL 字符串:
PreparedStatement pstmt = conn.prepareStatement( sql ) ;
由于名为 pstmt
的PreparedStatement
已经包含您的 SQL 语句,因此无需传递到 executeQuery
。
此错误可能是使用 Statement
复制粘贴某些代码以使用 PreparedStatement
在其他代码中重用的结果。