使用Java进行iReport时出错

我正在尝试用NetBeans中的iReport 5.5.0 Java发送一份报告。我遇到了一个错误，无法解决这个问题。下面是代码和错误

守则：

    try {
        Connection con = new ConnectionFactory().getConnection();

        ConectaBanco conecta = new ConectaBanco();
        conecta.conexao();
        PreparedStatement stmt = null;
        String sql = "SELECT l.codigo, l.nome_produto, l.composicao, DATE_FORMAT(l.data_aprovacao , '%d/%m/%Y'), co.nome as colecao, e.nome as estilista, DATE_FORMAT(l.data_inicio , '%d/%m/%Y'), DATE_FORMAT(l.data_termino , '%d/%m/%Y') from lote_producao as l INNER JOIN colecao as co INNER JOIN estilista as e ON co.codigo = l.colecao_codigo AND e.codigo = l.estilista_codigo AND l.codigo = "+codigo;
        stmt = con.prepareStatement(sql);
        ResultSet rs = stmt.executeQuery();
        JRResultSetDataSource relatResult = new JRResultSetDataSource(rs);
        JasperPrint jpPrint = JasperFillManager.fillReport("ireport/relLot.jasper", new HashMap(), relatResult);
        JasperViewer jv = new JasperViewer(jpPrint);
        jv.setVisible(true);
    } catch (SQLException ex) {
        Logger.getLogger(cadastro_lote_1.class.getName()).log(Level.SEVERE, null, ex);
    } catch (JRException ex) {
        Logger.getLogger(cadastro_lote_1.class.getName()).log(Level.SEVERE, null, ex);
    }

错误：

Exception in thread "AWT-EventQueue-0" java.lang.NoClassDefFoundError: javax/servlet/ServletOutputStream
at net.sf.jasperreports.web.util.WebResourceHandlersExtensionRegistryFactory.<clinit>(WebResourceHandlersExtensionRegistryFactory.java:47)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:270)
at net.sf.jasperreports.engine.util.JRClassLoader.loadClassForRealName(JRClassLoader.java:157)
at net.sf.jasperreports.engine.util.JRClassLoader.loadClassForName(JRClassLoader.java:115)

线程“AWT-EventQueue-0”java.lang.NoClassDefFoundError中的异常：javax/servlet/ServletOutputStream 位于net.sf.jasperreports.web.util.WebResourceHandlersExtensionRegistryFactory。（WebResourceHandlersExtensionRegistryFactory.java:47） 位于java.lang.Class.forName0（本机方法） 位于java.lang.Class.forName（Class.java:270） 位于net.sf.jasperreports.engine.util.JRClassLoader.loadClassForRealName（JRClassLoader.java:157） 位于net.sf.jasperreports.engine.util.JRClassLoader.loadClassForName（JRClassLoader.java:115）

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确保已导入此文件

import javax.servlet.ServletOutputStream;

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在类路径中找不到类javax.servlet.ServletOutputStream。您应该将其添加到项目中。@pL4Gu33添加到哪个库中？