Question

当我使用json填充子报表时，我遇到了JsonDataSource问题。这个问题已经被问到，但这些解决方案对我没有用，所以我需要帮助。我的json： { “JSON”：{ “人民”：[{ “名称”： “约瑟夫”}，{ “名称”： “ILDA”}]}}

我的JAVA代码：

 Map<String, Object> parameters = new HashMap<String, Object>();

    JasperDesign design = JRXmlLoader.load("C:\\tmp\\master.jrxml");
    JasperReport compiled = JasperCompileManager.compileReport(design);
    List<Map<String, String>> mappaPersone = new ArrayList<Map<String, String>>();
    Map<String, String> persona = new LinkedHashMap<String, String>();
    persona.put("name", "Joseph");
    Map<String, String> persona1 = new LinkedHashMap<String, String>();
    persona1.put("name", "Ilda");
    mappaPersone.add(persona);
    mappaPersone.add(persona1);
    Map<String, List<Map<String, String>>> mappaGen = new HashMap<String, List<Map<String, String>>>();
        mappaGen.put("Peoples", mappaPersone);
        Map<String, Map<String, List<Map<String, String>>>> jsonMap = new HashMap<String, Map<String, List<Map<String, String>>>>();
        jsonMap.put("json", mappaGen);
        Gson gson = new Gson();
        String json = gson.toJson(jsonMap);

        showMessage(json);

        InputStream is = new ByteArrayInputStream(json.getBytes("UTF-8"));
        JsonDataSource js = new JsonDataSource(is);
        parameters.put("REP_DS", js);

        JasperPrint report = JasperFillManager.fillReport(compiled, parameters,
                new JREmptyDataSource());


        SimplePdfExporterConfiguration configuration = new SimplePdfExporterConfiguration();
        JRPdfExporter exporter = new JRPdfExporter();
        exporter.setConfiguration(configuration);

        ExporterInput exporterInput = new SimpleExporterInput(report);
        exporter.setExporterInput(exporterInput);
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        OutputStreamExporterOutput exporterOutput = new SimpleOutputStreamExporterOutput(
                baos);
        exporter.setExporterOutput(exporterOutput);


        exporter.exportReport();



Exception in thread "main" net.sf.jasperreports.engine.fill.JRExpressionEvalException: Error evaluating expression for source text: ((net.sf.jasperreports.engine.data.JsonDataSource)$P{REP_DS}).subDataSource("json.Peoples")
    at net.sf.jasperreports.engine.fill.JREvaluator.evaluate(JREvaluator.java:264)
    at net.sf.jasperreport`enter code here`s.engine.fill.JRCalculator.evaluate(JRCalculator.java:610)
    at net.sf.jasperreports.engine.fill.JRCalculator.evaluate(JRCalculator.java:578)
    at net.sf.jasperreports.engine.fill.JRFillElement.evaluateExpression(JRFillElement.java:1015)
    at net.sf.jasperreports.engine.fill.JRFillSubreport.evaluateSubreport(JRFillSubreport.java:454)
    at net.sf.jasperreports.engine.fill.JRFillSubreport.evaluate(JRFillSubreport.java:345)
    at net.sf.jasperreports.engine.fill.JRFillElementContainer.evaluate(JRFillElementContainer.java:258)
    at net.sf.jasperreports.engine.fill.JRFillBand.evaluate(JRFillBand.java:454)
    at net.sf.jasperreports.engine.fill.JRVerticalFiller.fillColumnBand(JRVerticalFiller.java:2029)
    at net.sf.jasperreports.engine.fill.JRVerticalFiller.fillDetail(JRVerticalFiller.java:755)
    at net.sf.jasperreports.engine.fill.JRVerticalFiller.fillReportStart(JRVerticalFiller.java:262)
    at net.sf.jasperreports.engine.fill.JRVerticalFiller.fillReport(JRVerticalFiller.java:122)
    at net.sf.jasperreports.engine.fill.JRBaseFiller.fill(JRBaseFiller.java:551)
    at net.sf.jasperreports.engine.fill.BaseReportFiller.fill(BaseReportFiller.java:411)
    at net.sf.jasperreports.engine.fill.JRFiller.fill(JRFiller.java:122)
    at net.sf.jasperreports.engine.JasperFillManager.fill(JasperFillManager.java:667)
    at net.sf.jasperreports.engine.JasperFillManager.fillReport(JasperFillManager.java:983)
    at report.services.JSONTEST.generateReport(JSONTEST.java:105)
    at report.services.JSONTEST.main(JSONTEST.java:33)
Caused by: net.sf.jasperreports.engine.JRException: No node available. Iterate or rewind the data source.
    at net.sf.jasperreports.engine.data.JsonDataSource.subDataSource(JsonDataSource.java:455)
    at master_1437312305950_565620.evaluate(master_1437312305950_565620:173)
    at net.sf.jasperreports.engine.fill.JREvaluator.evaluate(JREvaluator.java:251)
    ... 18 more

我无法理解有什么问题...请帮助！

在我的主要报告jrxml中我有：

<parameter name="REP_DS" class="java.lang.Object"/>

和

<subreport>
            <reportElement positionType="Float" x="0" y="0" width="555" height="100" uuid="3f4dece2-5563-4df9-9cda-15623e0f6127"/>
            <dataSourceExpression><![CDATA[((net.sf.jasperreports.engine.data.JsonDataSource)$P{REP_DS}).subDataSource("json.Peoples")]]></dataSourceExpression>
            <subreportExpression><![CDATA["C:\\tmp\\slave.jasper"]]></subreportExpression>
        </subreport>

在子报告中：

<queryString language="json">
    <![CDATA[Peoples]]>
</queryString>
<field name="name" class="java.lang.String"/>
<title>
    <band height="79" splitType="Stretch">
        <textField>
            <reportElement x="35" y="33" width="100" height="20" uuid="32f70169-032d-4408-b84d-90ac06bbcad5"/>
            <textFieldExpression><![CDATA[$F{name}]]></textFieldExpression>
        </textField>
    </band>
</title>

不知道错误在哪里。

更新1：我通过将JsonDataSource传递给fillReport方法解决了异常问题：

JasperPrint report = JasperFillManager.fillReport(compiled, parameters,
            js);

现在进入.jrxml，我正在使用REPORT_DATA_SOURCE参数，所以我删除了REP_DS。

<dataSourceExpression><![CDATA[((net.sf.jasperreports.engine.data.JsonDataSource)$P{REPORT_DATA_SOURCE}).subDataSource("json.Peoples")]]></dataSourceExpression>

现在没有例外......但我有另一个问题。执行操作仅打印json列表的1个元素。它只打印约瑟夫而不是伊尔达。为什么？布局问题？如何制作可迭代的子报表？不要失败......

Answer 1

好的，现在我可以从json打印列表了。我不得不将字段放入细节带中，它的工作原理！

jasperreport / subreport

1 个答案: