Use the "Paper Style" framework in the Java class library to implement the printed report
Use the "Paper Style" framework in the Java class library to implement the printed report
Overview:
In many business systems, generating printed reports is a common demand.The Java class library provides many tools and frameworks to help us achieve this goal.One of the frameworks worthy of attention is the "Jasperreports" framework.It is an open source reporting tool that can be used to create various reports, including data reports, graphic reports, cross tables, etc.This article will introduce how to use the paper style framework to implement printed reports in Java.
Step 1: Add paper style dependencies
First of all, we need to add a paper style framework to our Java project.You can add dependencies through Maven or Gradle.The following is an example of using Maven to add paper styles:
<dependency>
<groupId>net.sf.jasperreports</groupId>
<artifactId>jasperreports</artifactId>
<version>6.15.0</version>
</dependency>
Step 2: Design report template
Next, we need to design a template for reporting.The report template is usually an XML file of JasperReports, which defines the structure, style and data of the report.You can use visual tools such as Jaspersoft Studio to design report templates, or manually write XML files.The following is a simple report template example:
<?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="report_template"
pageWidth="595"
pageHeight="842"
columnWidth="535"
leftMargin="20"
rightMargin="20"
topMargin="20"
bottomMargin="20">
<!-The title of the report->
<title>
<band height="50">
<staticText>
<text> <! [CDATA [Report Title]]> </Text>
</staticText>
</band>
</title>
<!-The data source and field of the statement->
<detail>
<band height="20">
<textField>
<reportElement x="0" y="0" width="100" height="20"/>
<textFieldExpression><![CDATA[$F{field1}]]></textFieldExpression>
</textField>
<textField>
<reportElement x="100" y="0" width="100" height="20"/>
<textFieldExpression><![CDATA[$F{field2}]]></textFieldExpression>
</textField>
<!-More field ...->
</band>
</detail>
</jasperReport>
Step 3: Fill in data and generate reports
Once we have a report template, we can use Java code to fill in data and generate reports.The following is a simple example:
import net.sf.jasperreports.engine.JRException;
import net.sf.jasperreports.engine.JasperCompileManager;
import net.sf.jasperreports.engine.JasperFillManager;
import net.sf.jasperreports.engine.JasperPrint;
import net.sf.jasperreports.engine.JasperReport;
import java.util.HashMap;
import java.util.Map;
public class ReportGenerator {
public static void main(String[] args) {
try {
// Compile report templates
JasperReport jasperReport = JasperCompileManager.compileReport("report_template.jrxml");
// Data input
Map<String, Object> parameters = new HashMap<>();
parameters.put("field1", "Value1");
parameters.put("field2", "Value2");
// Add more fields ...
JasperPrint jasperPrint = JasperFillManager.fillReport(jasperReport, parameters, new JREmptyDataSource());
// Generate report files (such as PDF)
JasperExportManager.exportReportToPdfFile(jasperPrint, "report.pdf");
} catch (JRException e) {
e.printStackTrace();
}
}
}
In the above example, we first compile the report templates through the method of `JaspercompileManager.CompileRewort ()` `` `).Then, fill the data with the method of using `jasperfillmanager.fillReport ()` method. The parameter `parameters` is a Map containing reporting fields and corresponding values.Finally, use the method to export the data to the PDF file after using the method of filling the data.
Summarize:
By using the paper style framework, we can implement printed reports in Java.First, we need to add the dependencies of the paper style framework, and then design the report template.Next, we can fill the data with Java code and generate reports.The paper -style framework provides a large number of functions and options, which can meet various reporting needs and have good scalability and flexibility.
