TIBCO JasperReports® is great for creating custom PDF templates, compiling them and then filling them with data (CSV, Query, etc).
However often the developer has a requirement to create dynamic PDF with any number of columns and data size and making it look well formatted too.
I have faced this same requirement at two different companies and this post is sharing my approach to solving this problem.
If you look at XML source of JasperReports template you will see a pattern there:
<?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="PDF Report"
pageWidth="940" pageHeight="842"
columnWidth="900"
leftMargin="20" rightMargin="20"
topMargin="20" bottomMargin="20"
uuid="0a409d27-e584-406c-9358-429837f98f4c">
<property name="com.jaspersoft.studio.data.defaultdataadapter"
value="CSV Adapter"/>
<queryString><![CDATA[]]></queryString>
<field name="Column Name 1" class="java.lang.String"/>
<field name="Column Name 2" class="java.lang.String"/>
...
<background>
<band splitType="Stretch"/>
</background>
<title>
<band height="79" splitType="Stretch"/>
</title>
<pageHeader>
<band height="35" splitType="Stretch"/>
</pageHeader>
<columnHeader>
<band height="35" splitType="Stretch">
<staticText>
<reportElement x="0" y="0" width="60" height="20"
uuid="ad347294-52c2-4aaf-b08b-859ff13fde71">
<property name="com.jaspersoft.studio.spreadsheet.connectionID"
value="48369fd4-1575-4e1a-a998-0d5e583d6232"/>
</reportElement>
<text><![CDATA[Column Name 1]></text>
</staticText>
<staticText>
<reportElement x="70" y="0" width="70" height="20"
uuid="c36b238b-1879-4272-9f4a-20d62cdf72d3">
<property name="com.jaspersoft.studio.spreadsheet.connectionID"
value="09356d5f-9603-402b-93b3-2805cbc5ce6f"/>
</reportElement>
<text><![CDATA[Column Name 2]]></text>
</staticText>
...
</band>
</columnHeader>
<detail>
<band height="47" splitType="Stretch">
<textField>
<reportElement x="0" y="0" width="60" height="20"
uuid="7004bb57-f42f-438f-9da2-fb9613e8a86b">
<property name="com.jaspersoft.studio.spreadsheet.connectionID"
value="48369fd4-1575-4e1a-a998-0d5e583d6232"/>
</reportElement>
<textFieldExpression>
<![CDATA[$F{Column Name 1}]]>
</textFieldExpression>
</textField>
<textField>
<reportElement x="70" y="0" width="70" height="20"
uuid="e1330b87-e5aa-4202-bdf5-9972555f8c20">
<property name="com.jaspersoft.studio.spreadsheet.connectionID"
value="09356d5f-9603-402b-93b3-2805cbc5ce6f"/>
</reportElement>
<textFieldExpression>
<![CDATA[$F{Column Name 2}]]>
</textFieldExpression>
</textField>
...
</band>
</detail>
<pageFooter>
<band height="54" splitType="Stretch"/>
</pageFooter>
<summary>
<band height="42" splitType="Stretch"/>
</summary>
</jasperReport>You have staticText tag for each column and textField for a value for that corresponding column
Also notice that property/@value attribute shares the same UUID value.
Then next column x attribute is incremented by width of first column + some padding value.
Once you understand how XML is formed - it’s easy to write a logic for dynamically generating similar looking XML template dynamically based on any data provided.
I am just posting the end result in Java that generates, compiles and fills the PDF report from CSV data also taking into account resizing columns width based on data size provided (just inspecting first 10 rows for performance reasons). Feel free to use this example, extend it and modify to fit your needs:
package com.jasper.generator;
import net.sf.jasperreports.engine.*;
import net.sf.jasperreports.engine.data.JRCsvDataSource;
import org.apache.log4j.Logger;
import java.io.*;
import java.nio.charset.Charset;
import java.util.HashMap;
import java.util.Map;
import java.util.UUID;
/**
* Generates PDF report using JasperReports lib
*
* @author Eugene Luzgin, August 2019
*/
public class JasperReportGenerator {
static final Logger logger = Logger.getLogger(JasperReportGenerator.class);
private static final int min_page_width = 555;
private static final int col_width = 80;
private static final int col_pad = 10;
private static final int col_height = 20;
/** copy the file to the output stream */
public void writePDF(OutputStream pdfOut, File csvFile) throws IOException {
try {
// Read first line from CSV file as columns:
BufferedReader csvReader = new BufferedReader(new FileReader(csvFile));
String columnsLine = csvReader.readLine();
String[] columns = columnsLine.split(",");
Map<String, Integer> colAvgLen = new HashMap<>(columns.length);
for (String column : columns) {
colAvgLen.put(column, column.length());
}
String line;
int counter = 0;
while ((line = csvReader.readLine()) != null && counter < 10) {
String[] values = line.split(",");
for (int i = 0; i < columns.length; i++) {
String col = columns[i];
Integer len = (values[i] != null) ? values[i].length() : 0;
if (colAvgLen.get(col) < len) colAvgLen.put(col, len);
}
counter++;
}
csvReader.close();
Map<String, Float> colAvgPerWidth = convertAbsoluteAveragesToPercents(colAvgLen);
// construct and run JasperReports:
JasperPrint jprint = createJasperReport(csvFile, columns, colAvgPerWidth);
JasperExportManager.exportReportToPdfStream(jprint, pdfOut);
} catch (JRException jrex) {
logger.error("JasperReports error", jrex);
throw new IOException("Error generating PDF report", jrex);
}
}
private Map<String, Float> convertAbsoluteAveragesToPercents(Map<String, Integer> colAvgLen) {
Map<String, Float> colAvgPer = new HashMap<>(colAvgLen.size());
Integer total = 0;
for (String col : colAvgLen.keySet()) {
total += colAvgLen.get(col);
}
for (String col : colAvgLen.keySet()) {
Float percent = (100.0F * colAvgLen.get(col).floatValue()) / total;
colAvgPer.put(col, percent);
}
return colAvgPer;
}
private JasperPrint createJasperReport(
File csvFile, String[] columns, Map<String, Float> colAvgPerWidth)
throws JRException, IOException {
InputStream csvIn = new FileInputStream(csvFile);
JRCsvDataSource jrCsvDataSource = new JRCsvDataSource(csvIn);
jrCsvDataSource.setUseFirstRowAsHeader(true);
jrCsvDataSource.setColumnNames(columns);
String xmlReport = createJasperXMLReport(columns, colAvgPerWidth);
InputStream inputStream =
new ByteArrayInputStream(xmlReport.getBytes(Charset.forName("UTF-8")));
JasperReport report = JasperCompileManager.compileReport(inputStream);
Map<String, Object> parameters = new HashMap<>();
return JasperFillManager.fillReport(report, parameters, jrCsvDataSource);
}
private String createJasperXMLReport(String[] columns, Map<String, Float> colAvgPerWidth) {
Map<String, String> propUUIDMap = new HashMap<>(columns.length);
int columnsTotalWidth = (col_width + col_pad) * columns.length;
Map<String, Integer> columnWidthMap = new HashMap<>(columns.length);
for (String column : colAvgPerWidth.keySet()) {
Float ratio = colAvgPerWidth.get(column) / 100;
Integer colWidth = Math.round(columnsTotalWidth * ratio);
columnWidthMap.put(column, colWidth);
}
int pageWidth = columnsTotalWidth + 40;
if (pageWidth < min_page_width) pageWidth = min_page_width;
UUID reportUUID = UUID.randomUUID();
StringBuffer sb = new StringBuffer();
sb.append(
"<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n"
+ "<!-- Created with Jaspersoft Studio version 6.9.0.final using JasperReports Library version 6.9.0-cb8f9004be492ccc537180b49c026951f4220bf3 -->\n"
+ "<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=\"PDF Report\" "
+ "pageWidth=\""
+ pageWidth
+ "\" pageHeight=\"842\" columnWidth=\""
+ columnsTotalWidth
+ "\" leftMargin=\"20\" rightMargin=\"20\" topMargin=\"20\" bottomMargin=\"20\" uuid=\""
+ reportUUID
+ "\">\n"
+ "\t<property name=\"com.jaspersoft.studio.data.defaultdataadapter\" value=\"CSV Adapter\"/>\n"
+ "\t<queryString>\n"
+ "\t\t<![CDATA[]]>\n"
+ "\t</queryString>\n");
for (String column : columns) {
sb.append("<field name=\"");
sb.append(column);
sb.append("\" class=\"java.lang.String\"/>\n");
}
sb.append(
"\t<background>\n"
+ "\t\t<band splitType=\"Stretch\"/>\n"
+ "\t</background>\n"
+ "\t<title>\n"
+ "\t\t<band height=\"79\" splitType=\"Stretch\"/>\n"
+ "\t</title>\n"
+ "\t<pageHeader>\n"
+ "\t\t<band height=\"35\" splitType=\"Stretch\"/>\n"
+ "\t</pageHeader>\n"
+ "\t<columnHeader>\n"
+ "\t\t<band height=\"35\" splitType=\"Stretch\">\n");
int x = 0;
for (String column : columns) {
UUID elemUUID = UUID.randomUUID();
UUID propUUID = UUID.randomUUID();
propUUIDMap.put(column, propUUID.toString());
sb.append(
"\t\t\t<staticText>\n"
+ "\t\t\t\t<reportElement x=\""
+ x
+ "\" y=\"0\" width=\""
+ columnWidthMap.get(column)
+ "\" height=\""
+ col_height
+ "\" uuid=\"");
sb.append(elemUUID.toString());
sb.append("\">\n");
sb.append(
"\t\t\t\t\t<property name=\"com.jaspersoft.studio.spreadsheet.connectionID\" value=\"");
sb.append(propUUID.toString());
sb.append("\"/>\n");
sb.append("\t\t\t\t</reportElement>\n");
sb.append("\t\t\t\t<text><![CDATA[");
sb.append(column);
sb.append("]]></text>\n");
sb.append("\t\t\t</staticText>\n");
x += columnWidthMap.get(column) + col_pad;
}
sb.append(
"\t\t</band>\n"
+ "\t</columnHeader>\n"
+ "\t<detail>\n"
+ "\t\t<band height=\"47\" splitType=\"Stretch\">\n");
x = 0;
for (String column : columns) {
UUID elemUUID = UUID.randomUUID();
String propUUID = propUUIDMap.get(column);
sb.append(
"\t\t\t<textField>\n"
+ "\t\t\t\t<reportElement x=\""
+ x
+ "\" y=\"0\" width=\""
+ columnWidthMap.get(column)
+ "\" height=\""
+ col_height
+ "\" uuid=\"");
sb.append(elemUUID.toString());
sb.append("\">\n");
sb.append(
"\t\t\t\t\t<property name=\"com.jaspersoft.studio.spreadsheet.connectionID\" value=\"");
sb.append(propUUID);
sb.append("\"/>\n");
sb.append("\t\t\t\t</reportElement>\n" + "\t\t\t\t<textFieldExpression><![CDATA[$F{");
sb.append(column);
sb.append("}]]></textFieldExpression>\n" + "\t\t\t</textField>\n");
x += columnWidthMap.get(column) + col_pad;
}
sb.append(
"\t\t</band>\n"
+ "\t</detail>\n"
+ "\t<pageFooter>\n"
+ "\t\t<band height=\"54\" splitType=\"Stretch\"/>\n"
+ "\t</pageFooter>\n"
+ "\t<summary>\n"
+ "\t\t<band height=\"42\" splitType=\"Stretch\"/>\n"
+ "\t</summary>\n"
+ "</jasperReport>");
return sb.toString();
}
}
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