org.springframework.jdbc。BadSqlGrammarException:StatementCallback;坏的SQL语法

HTTP Status 500 - Request processing failed; nested exception is org.springframework.jdbc.BadSqlGrammarException: StatementCallback; bad SQL grammar [select * from assignment where username=reza]; nested exception is com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Unknown column 'reza' in 'where clause'
HTTP Status 500 - Request processing failed; ne