来自字符串的数据源 [英] Data Source from string

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本文介绍了来自字符串的数据源的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

我想使用我传入Java的args字符串作为数据源来填充我的报告。我一直在尝试从字符串创建一个JRXmlDataSource以传递到fillreport。我已经尝试将字符串转换为Doc，将字符串转换为文件流，然后直接加载字符串。我甚至试图创建一个文件并以这种方式加载它但没有任何作用。任何帮助，将不胜感激。

I'm wanting to use a args string that I'm passing into Java as a data source to fill my report. I have been attempting to create a JRXmlDataSource from the string to pass into fillreport. I've tried converting the string to a Doc, convert the string into a filestream, and just loading the string directly. I have even attempted to just create a file and load it in that way but nothing works. Any help would be appreciated.

主要方法：

public class Testing {

    public static void main(String[] args) throws JRException {
        try {
            String xmlData = args[0];
            JasperReport jasperReport = null;
            String path = "C:/workspace/testProject/testing/sources/";
            JasperPrint jasperPrint = null;

            Document doc = convertStringToDocument(xmlData);
            JRXmlDataSource xmlDataSource = new JRXmlDataSource(doc);

            //Provide path for your JRXML template.
            String templateName = path + "report2.jrxml";

            //Provide path for your final pdf file.
            String destinationFile = path + "ReportSQL.pdf";

            //Compiling the template.
            jasperReport = JasperCompileManager.compileReport(templateName);

            //Sending a parameter with the logged in user name as value
            HashMap parameters = new HashMap();

            // Filling the report template with data
            jasperPrint = JasperFillManager.fillReport(jasperReport, parameters, xmlDataSource);

            //Sending a Complete print of the report.
            JasperPrintManager.printReport(jasperPrint, true);

            //Exporting it to an PDF
            JasperExportManager.exportReportToPdfFile(jasperPrint, destinationFile);

        } catch (Exception e) {
            System.out.println(e);
        }
    }

    private static Document convertStringToDocument(String xmlStr) {
        DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
        DocumentBuilder builder;
        try {
            builder = factory.newDocumentBuilder();
            Document doc = builder.parse(new InputSource(new StringReader(xmlStr)));
            return doc;
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }
}

来源字符串：

 <?xml version="1.0" encoding="UTF-8"?>
 <DATA>
  <ROW>
    <ID>1</ID>
    <firstName>Testname</firstName>
    <lastName>Testlast</lastName>
    <code>12345</code>
 </ROW>
 <ROW>
    <ID>2</ID>
    <firstName>John</firstName>
    <lastName>Doe</lastName>
    <code>54321</code>
 </ROW>
 <ROW>
    <ID>3</ID>
    <firstName>Jane</firstName>
    <lastName>Doe</lastName>
    <code>22222</code>
</ROW>
<ROW>
    <ID>4</ID>
    <firstName>George</firstName>
    <lastName>Washington</lastName>
    <code>33333</code>
</ROW>
<ROW>
    <ID>5</ID>
    <firstName>John</firstName>
    <lastName>Adams</lastName>
    <code>44444</code>
</ROW>
<ROW>
    <ID>6</ID>
    <firstName>Thomas </firstName>
    <lastName>Jefferson</lastName>
    <code>55555</code>
</ROW>
<ROW>
    <ID>7</ID>
    <firstName>James</firstName>
    <lastName>Madison</lastName>
    <code>66666</code>
</ROW>
<ROW>
    <ID>8</ID>
    <firstName>James</firstName>
    <lastName>Monroe</lastName>
    <code>77777</code>
</ROW>
<ROW>
    <ID>9</ID>
    <firstName>John Quency</firstName>
    <lastName>Adams</lastName>
    <code>88888</code>
 </ROW>
 <ROW>
    <ID>10</ID>
    <firstName>Andrew</firstName>
    <lastName>Jackson</lastName>
    <code>99999</code>
 </ROW>
 <ROW>
    <ID>11</ID>
    <firstName>Martin Van</firstName>
    <lastName>Burren</lastName>
    <code>0</code>
 </ROW>
  </DATA>

Jasper XML --- report2.jrxml：

Jasper XML---report2.jrxml: 

     <?xml version="1.0" encoding="UTF-8"?>
    <jasperReport xmlns="http://jasperreports.sourceforge.net/jasperreports"      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://jasperreports.sourceforge.net/jasperreports http://jasperreports.sourceforge.net/xsd/jasperreport.xsd" name="report1" language="groovy" pageWidth="595" pageHeight="842" columnWidth="555" leftMargin="20" rightMargin="20" topMargin="20" bottomMargin="20" uuid="5263a626-fdd2-43a7-b67e-ced19b4c240b">
        <property name="ireport.zoom" value="1.0"/>
        <property name="ireport.x" value="0"/>
        <property name="ireport.y" value="0"/>
        <field name="firstName" class="java.lang.String">
            <fieldDescription><![CDATA[]]></fieldDescription>
        </field>
        <field name="lastName" class="java.lang.String">
              <fieldDescription><![CDATA[]]></fieldDescription>
        </field>
        <field name="code" class="java.lang.Integer">
             <fieldDescription><![CDATA[]]></fieldDescription>
        </field>
        <variable name="testout" class="java.lang.Integer">
              <variableExpression><![CDATA[$V{testout}.valueOf($V{testout}.intValue() + 1 )]]></variableExpression>
              <initialValueExpression><![CDATA[$V{testout}.intValue(0)]]></initialValueExpression>
        </variable>
        <variable name="variable1" class="java.lang.String"/>
        <background>
            <band splitType="Stretch"/>
        </background>
        <title>
          <band height="71" splitType="Stretch">
           <staticText>
             <reportElement mode="Opaque" x="0" y="2" width="555" height="55" forecolor="#000000" backcolor="#6699FF" uuid="d2f1857a-a53f-4b65-8960-ff56856000c4"/>
               <textElement textAlignment="Center">
                   <font fontName="SansSerif" size="40"/>
               </textElement>
                <text><![CDATA[People Test]]></text>
             </staticText>
          </band>
      </title>
    <pageHeader>
        <band height="16" splitType="Stretch"/>
    </pageHeader>
    <columnHeader>
        <band height="33" splitType="Stretch">
            <elementGroup>
                <staticText>
                    <reportElement mode="Opaque" x="360" y="0" width="195" height="20" backcolor="#999999" uuid="2311af72-d724-4003-b5e4-151bc23e41a8"/>
                    <textElement textAlignment="Center">
                        <font size="14" isBold="true"/>
                    </textElement>
                    <text><![CDATA[Code]]></text>
                 </staticText>
                 <staticText>
                    <reportElement mode="Opaque" x="168" y="0" width="192" height="20" backcolor="#999999" uuid="0fc99eec-a7c3-468f-ba64-30f3140131b2"/>
                    <textElement textAlignment="Center">
                        <font size="14" isBold="true"/>
                    </textElement>
                    <text><![CDATA[Last]]></text>
                </staticText>
                <staticText>
                    <reportElement mode="Opaque" x="0" y="0" width="168" height="20" backcolor="#999999" uuid="b0a4ccab-fff0-4a77-ad52-1e4132a627e2"/>
                    <textElement textAlignment="Center">
                        <font size="14" isBold="true"/>
                    </textElement>
                    <text><![CDATA[First ]]></text>
                </staticText>
            </elementGroup>
         </band>
     </columnHeader>
     <detail>
         <band height="36" splitType="Stretch">
            <textField>
                <reportElement x="0" y="0" width="168" height="20" uuid="ca9be109-f4d6-48d6-988f-a5d78352e578"/>
                <textElement textAlignment="Center"/>
                <textFieldExpression><![CDATA[$F{firstName}]]></textFieldExpression>
             </textField>
            <textField>
                <reportElement x="168" y="0" width="192" height="20" uuid="1255a5e6-59b1-4d49-92e0-c6b64a0cbf93"/>
                <textElement textAlignment="Center"/>
                <textFieldExpression><![CDATA[$F{lastName}]]></textFieldExpression>
            </textField>
            <textField>
                <reportElement x="360" y="0" width="195" height="20" uuid="1099096e-17b7-480c-8e9c-ffb50669326a"/>
                <textElement textAlignment="Center"/>
                <textFieldExpression><![CDATA[$F{code}]]></textFieldExpression>
            </textField>
         </band>
     </detail>
     <columnFooter>
        <band height="28" splitType="Stretch"/>
     </columnFooter>
     <pageFooter>
         <band height="214" splitType="Stretch">
            <image>
                <reportElement mode="Opaque" x="194" y="0" width="166" height="178" backcolor="#000000" uuid="4299a501-2792-4c76-bc6d-506a480fa1a6"/>
                <imageExpression><![CDATA["C:\\workspace\\testProject\\testing\\sources\\Turkish_Van_Cat.jpg"]]></imageExpression>
            </image>
             <textField>
                <reportElement x="197" y="198" width="163" height="16" uuid="801deb03-5452-4bc6-935e-2c15a8977721"/>
                <textElement textAlignment="Center"/>
                <textFieldExpression><![CDATA[$V{PAGE_NUMBER}]]></textFieldExpression>
            </textField>
        </band>
     </pageFooter>
     <summary>
        <band height="104" splitType="Stretch"/>
    </summary>
 </jasperReport>


推荐答案

您的字段元素不包含XML路径表达式。试试这个：

Your field elements do not contain XML path expressions. Try this:

<field name="firstName" class="java.lang.String">
    <fieldDescription><![CDATA[DATA/ROW/firstName]]></fieldDescription>
 </field>
 <field name="lastName" class="java.lang.String">
   <fieldDescription><![CDATA[DATA/ROW/lastName]]></fieldDescription>
 </field>
 <field name="code" class="java.lang.Integer">
   <fieldDescription><![CDATA[DATA/ROW/code]]></fieldDescription>
 </field>

此外，我有时会采用一些小技巧。在 JRXmlDataSource 周围创建一个包装器类，在Jasper检索它们时转储字段的内容：

Also, there's a little trick I employ sometimes. Create a wrapper class around JRXmlDataSource that dumps the contents of the fields as Jasper retrieves them:

package <your package here>;
import net.sf.jasperreports.engine.JRException;
import net.sf.jasperreports.engine.JRField;
import net.sf.jasperreports.engine.data.JRXmlDataSource;

public class MyXmlDataSource extends JRXmlDataSource {

    public MyXmlDataSource(String x, String y) throws JRException
    {
        super(x,y);
    }

    public Object getFieldValue(JRField jrField) throws JRException {
        Object ret = super.getFieldValue(jrField);
        System.out.println(ret);
        return ret;
    }
}

然后，而不是实例化 JRXmlDataSource ，实例化 MyXmlDataSource 。这将告诉您Jasper从您的XML中检索哪些元素。

Then, instead of instantiating JRXmlDataSource, instantiate MyXmlDataSource instead. This will let you know which elements are being retrieved by Jasper from your XML.

这篇关于来自字符串的数据源的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！

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