Web服务错误删除

Webservice error delete

您好,我正在尝试 运行 我的网络服务中的查询,但是查询所在的函数从无到有中断。

我的代码:

public boolean excluir(String usuario)
{
String sql = "DELETE * FROM listaproduto where uclogin=?";
Boolean retorno = false;
PreparedStatement pst = Conexao.getPreparedStatement(sql);
try {
    pst.setString(1, usuario); //He breaks that part.
    if(pst.executeUpdate()>0)
    {
        retorno = true;
    }
} catch (SQLException ex) {
    Logger.getLogger(ProdutoDAO.class.getName()).log(Level.SEVERE, null, ex);
    retorno = false;
}
return retorno;
} 

错误:

GET SolicitaçãoFailed RequestFailed --> Status: (500) Resposta: { HTTP Status 500 - Internal Server Error

type Exception report

messageInternal Server Error

descriptionThe server encountered an internal error that prevented it from fulfilling this request.

exception

javax.servlet.ServletException: java.lang.NullPointerException

root cause

java.lang.NullPointerException

注意 GlassFish Server Open Source Edition 4.1.1 日志中提供了异常的完整堆栈跟踪及其根本原因。 GlassFish Server 开源版 4.1.1

String sql = "DELETE FROM listaproduto where uclogin=?";

删除你的''然后再试一次..我认为删除方法不需要''.. 希望这可以帮助你:)