JDBC DatabaseMetaData说我的mysql服务器不支持namedParameters，因此抛出空指针异常

Question

Im back on java recently, and i am struggling making the following method work:

@Override
public T createEntity(T entity) throws SQLException{
    DatabaseMetaData dbMeta  = connection.getMetaData();
    boolean okay = dbMeta.supportsNamedParameters();
    if(okay) {
        System.out.println("Supports named arguments");
    } else {
        System.out.println("Does not support named arguments");
    }
    CallableStatement cstmt = connection.prepareCall("create_" + table.getName() + "(" + columns.stream().map( column -> "?").collect(Collectors.joining(","))  + ")");

    final ThrowingConsumer<DatabaseColumn> throwingConsumer = column -> {
       try {
        String alright = "herpderp";
        cstmt.setObject(column.getName(), entity.getClass().getDeclaredField(column.getName()).get(entity) /**, SQLType targetSqlType ?? */ );
           ParameterMetaData meta =   cstmt.getParameterMetaData();
       } catch(Exception e) {
           e.printStackTrace();
       }
    };
    columns.stream().forEach(throwingConsumer);

    cstmt.execute();
    return null;
}

The call:

cstmt.setObject(column.getName(), entity.getClass().getDeclaredField(column.getName()).get(entity) /**, SQLType targetSqlType ?? */ );

Fails with a nullpointer exception, i have checked that both of the values goes in are just fine, but eventually it just does a null pointer. The prepared statement also looks just fine. I am trying to use namedParameters so that is what i think is the culprit, i tried to check if my setup was even compatible with namedParameters, and it turns out that DatabaseMetaData doesn't think so, in the following code:

DatabaseMetaData dbMeta  = connection.getMetaData();
boolean okay = dbMeta.supportsNamedParameters();
if(okay) {
    System.out.println("Supports named arguments");
} else {
    System.out.println("Does not support named arguments");
}

. The following is my versions:

    compile group: 'mysql', name: 'mysql-connector-java', version: '6.0.3'

    mysql: mysql  Ver 14.14 Distrib 5.7.13, for Linux (x86_64) using  EditLine wrapper

so pretty much the newest of the newest.

If i run through it with the debugger, a scenario where this gives a nullpointer looks like this:

cstmt.setObject("email", "herpderp@gmail.com");

Where the orginalSql field in the callableStatement looks like this:

create_account(?, ?, ?, ?, ?)

The stored procedure looks like this:

CREATE DEFINER=`root`@`localhost` PROCEDURE `create_account`(email VARCHAR(45), username VARCHAR (45), pw VARCHAR (45), guid VARCHAR(45), verified tinyint(4))
BEGIN
insert into account (`email`, `username`, `password`, `guid`, `verified`) values (email, username, pw, guid, verified);
END

Thanks

Answer 1

When calling a stored procedure, it goes like this:

 CallableStatement cstmt = connection.prepareCall("{CALL create_" + table.getName() + "(" + columns.stream().map( column -> "?").collect(Collectors.joining(","))  + ")}");

Without the CALL, its no good, wouldve just wished the error messages was more helpful, obviously a complete brainfart :)