Jasper Reports 简明教程

Reports Parameters

填充报告的主要输入是− 报告模板、参数和数据源。本章将介绍参数，在下一章中我们将讨论数据源。

参数是对象引用，在报告填充操作期间传递给报告引擎。无法通过数据源传递的数据可以通过使用参数传递。可以通过参数传递诸如作者姓名、报告标题等数据。JasperReports 模板或 JRXML 模板可以具有零个或多个参数元素。

Parameter Declaration

参数声明如下−

<parameter name = "exampleParameter" class = "java.lang.String" />

The Name Attribute

<parameter> 元素的 name 属性是必需的。它通过名称引用报告表达式中的参数。参数名称应为一个单词。它不应包含任何特殊字符，例如句点或逗号。

The Class Attribute

class 属性也是必需的，它为参数值指定类名。它的默认值为 java.lang.String。这可以更改为运行时可用的任何类。无论报告参数的类型如何，引擎都会负责强制转换报告表达式中使用 $P{} 令牌的内容，从而使手动强制转换变得不必要。

报表参数值始终打包在一个 java.util.Map 对象中，其具有参数名称作为其键。报表参数可以用在报表的查询字符串中，以进一步定制从数据库中检索出的数据集。它们的作用就像查询中的动态过滤器，向报表提供数据。

Built-in Parameters

以下是预定义的报表参数，可随时用于表达式中：

S.NO	Parameter Name and Description
1	REPORT_PARAMETERS_MAP 包含一个映射，其中具有所有用户定义和内置参数。
2	REPORT_CONNECTION 指向用户提供的类 java.sql.Connection，用于 JDBC 数据源。
3	REPORT_DATA_SOURCE 这是由用户提供的 JRDataSource 实例，它表示内置数据源类型或用户自定义类型中的一个。
4	REPORT_MAX_COUNT 这是一个 java.lang.Integer 值，允许用户限制来自数据源的记录。
5	REPORT_SCRIPTLET 指向 net.sf.jasperreports.engine.JRAbstractScriptlet，并包含由用户提供的报表小脚本的实例。
6	REPORT_LOCALE 这是一个 java.util.Locale 实例，包含所需的资源包语言环境。
7	REPORT_RESOURCE_BUNDLE 指向 java.util.ResourceBundle 对象，并包含本地化消息。
8	REPORT_TIME_ZONE 这是一个 java.util.TimeZone 实例，用于日期格式化。
9	REPORT_VIRTUALIZER 这是一个 net.sf.jasperreports.engine.JRVirtualizer 对象，用于页面虚拟化（优化内存消耗）。
10	REPORT_CLASS_LOADER 这是一个 java.lang.ClassLoader 实例，在报表填充过程中使用以加载资源，例如图像、字体和子报表模板
11	IS_IGNORE_PAGINATION 如果设置为 java.lang.Boolean.TRUE，则报表将生成在一个长页面上，并且不会出现分页符。

Example

让我们将 ReportTitle 和 Author 传递给报表（由 JasperReportFill.java 生成）。修改后的文件 C:\tools\jasperreports-5.0.1\test\src\com\tutorialspoint\JasperReportFill.java 如下：

package com.tutorialspoint;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;

import net.sf.jasperreports.engine.JRException;
import net.sf.jasperreports.engine.JasperFillManager;
import net.sf.jasperreports.engine.data.JRBeanCollectionDataSource;

public class JasperReportFill {
   @SuppressWarnings("unchecked")
   public static void main(String[] args) {
      String sourceFileName =
         "C://tools/jasperreports-5.0.1/test/jasper_report_template.jasper";

      DataBeanList DataBeanList = new DataBeanList();
      ArrayList<DataBean> dataList = DataBeanList.getDataBeanList();

      JRBeanCollectionDataSource beanColDataSource =
      new JRBeanCollectionDataSource(dataList);

      Map parameters = new HashMap();
      /**
       * Passing ReportTitle and Author as parameters
       */
      parameters.put("ReportTitle", "List of Contacts");
      parameters.put("Author", "Prepared By Manisha");

      try {
         JasperFillManager.fillReportToFile(
         sourceFileName, parameters, beanColDataSource);
      } catch (JRException e) {
         e.printStackTrace();
      }
   }
}

POJO 文件 C:\tools\jasperreports-5.0.1\test\src\com\tutorialspoint\DataBean.java 的内容如下：

package com.tutorialspoint;

public class DataBean {
   private String name;
   private String country;

   public String getName() {
      return name;
   }

   public void setName(String name) {
      this.name = name;
   }

   public String getCountry() {
      return country;
   }

   public void setCountry(String country) {
      this.country = country;
   }
}

C:\tools\jasperreports-5.0.1\test\src\com\tutorialspoint\DataBeanList.java 文件的内容如下 −

package com.tutorialspoint;

import java.util.ArrayList;

public class DataBeanList {
   public ArrayList<DataBean> getDataBeanList() {
      ArrayList<DataBean> dataBeanList = new ArrayList<DataBean>();

      dataBeanList.add(produce("Manisha", "India"));
      dataBeanList.add(produce("Dennis Ritchie", "USA"));
      dataBeanList.add(produce("V.Anand", "India"));
      dataBeanList.add(produce("Shrinath", "California"));

      return dataBeanList;
   }

   /**
    * This method returns a DataBean object,
    * with name and country set in it.
    */
   private DataBean produce(String name, String country) {
      DataBean dataBean = new DataBean();
      dataBean.setName(name);
      dataBean.setCountry(country);

      return dataBean;
   }
}

让我们将参数 <*ReportTitle*> 和 <*Author*> 添加到我们的现有报表模板（第 Report Designs 章）。报表标题和作者将显示在报表开头。修改后的报表模板（jasper_report_template.jrxml）如下。将其保存到 C:\tools\jasperreports-5.0.1\test 目录中：

<?xml version = "1.0"?>
<!DOCTYPE jasperReport PUBLIC
   "//JasperReports//DTD Report Design//EN"
   "http://jasperreports.sourceforge.net/dtds/jasperreport.dtd">

<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 = "jasper_report_template" pageWidth = "595"
   pageHeight = "842" columnWidth = "515"
   leftMargin = "40" rightMargin = "40" topMargin = "50" bottomMargin = "50">

   <parameter name = "ReportTitle" class = "java.lang.String"/>
   <parameter name = "Author" class = "java.lang.String"/>

   <queryString>
      <![CDATA[]]>
   </queryString>

   <field name = "country" class = "java.lang.String">
      <fieldDescription><![CDATA[country]]></fieldDescription>
   </field>

   <field name = "name" class = "java.lang.String">
      <fieldDescription><![CDATA[name]]></fieldDescription>
   </field>

   <title>
      <band height = "70">

         <line>
            <reportElement x = "0" y = "0" width = "515" height = "1"/>
         </line>

         <textField isBlankWhenNull = "true" bookmarkLevel = "1">
            <reportElement x = "0" y = "10" width = "515" height = "30"/>

            <textElement textAlignment = "Center">
               <font size = "22"/>
            </textElement>

            <textFieldExpression class = "java.lang.String">
               <![CDATA[$P{ReportTitle}]]>
            </textFieldExpression>

            <anchorNameExpression>
               <![CDATA["Title"]]>
            </anchorNameExpression>
         </textField>

         <textField isBlankWhenNull = "true">
            <reportElement  x = "0" y = "40" width = "515" height = "20"/>

            <textElement textAlignment = "Center">
               <font size = "10"/>
            </textElement>

            <textFieldExpression class = "java.lang.String">
               <![CDATA[$P{Author}]]>
            </textFieldExpression>
         </textField>

      </band>
   </title>

   <columnHeader>
      <band height = "23">

         <staticText>
            <reportElement mode = "Opaque" x = "0" y = "3" width = "535" height = "15"
               backcolor = "#70A9A9" />

            <box>
               <bottomPen lineWidth = "1.0" lineColor = "#CCCCCC" />
            </box>

            <textElement />

            <text>
               <![CDATA[]]>
            </text>
         </staticText>

         <staticText>
            <reportElement x = "414" y = "3" width = "121" height = "15" />

            <textElement textAlignment = "Center" verticalAlignment = "Middle">
               <font isBold = "true" />
            </textElement>

            <text>
               <![CDATA[Country]]>
            </text>
         </staticText>

         <staticText>
            <reportElement x = "0" y = "3" width = "136" height = "15" />

            <textElement textAlignment = "Center" verticalAlignment = "Middle">
               <font isBold = "true" />
            </textElement>

            <text><![CDATA[Name]]></text>
         </staticText>

      </band>
   </columnHeader>

   <detail>
      <band height = "16">

         <staticText>
            <reportElement mode = "Opaque" x = "0" y = "0" width = "535" height = "14"
               backcolor = "#E5ECF9" />

            <box>
               <bottomPen lineWidth = "0.25" lineColor = "#CCCCCC" />
            </box>

            <textElement />

            <text>
               <![CDATA[]]>
            </text>
         </staticText>

         <textField>
            <reportElement x = "414" y = "0" width = "121" height = "15" />

            <textElement textAlignment = "Center" verticalAlignment = "Middle">
               <font size = "9" />
            </textElement>

            <textFieldExpression class = "java.lang.String">
               <![CDATA[$F{country}]]>
            </textFieldExpression>
         </textField>

         <textField>
            <reportElement x = "0" y = "0" width = "136" height = "15" />
            <textElement textAlignment = "Center" verticalAlignment = "Middle" />

            <textFieldExpression class = "java.lang.String">
               <![CDATA[$F{name}]]>
            </textFieldExpression>
         </textField>

      </band>
   </detail>

</jasperReport>

Report Generation

我们将使用常规的 ANT 构建过程编译并执行以上文件。文件 build.xml（保存在 C:\tools\jasperreports-5.0.1\test 目录下）的内容如下。

导入文件 - baseBuild.xml 从第 Environment Setup 章选取并应该放置在与 build.xml 相同的目录中。

<?xml version = "1.0" encoding = "UTF-8"?>
<project name = "JasperReportTest" default = "viewFillReport" basedir = ".">
   <import file = "baseBuild.xml" />

   <target name = "viewFillReport" depends = "compile,compilereportdesing,run"
      description = "Launches the report viewer to preview
      the report stored in the .JRprint file.">


      <java classname = "net.sf.jasperreports.view.JasperViewer" fork = "true">
         <arg value = "-F${file.name}.JRprint" />
         <classpath refid = "classpath" />
      </java>
   </target>

   <target name = "compilereportdesing" description = "Compiles the JXML file and
      produces the .jasper file.">

      <taskdef name = "jrc" classname = "net.sf.jasperreports.ant.JRAntCompileTask">
         <classpath refid = "classpath" />
      </taskdef>

      <jrc destdir = ".">
         <src>
            <fileset dir = ".">
               <include name = "*.jrxml" />
            </fileset>
         </src>
         <classpath refid = "classpath" />
      </jrc>

   </target>

</project>

接下来，让我们打开命令行窗口并转到放置 build.xml 的目录。最后，执行以下命令 ant -Dmain-class=com.tutorialspoint.JasperReportFill （viewFullReport 是默认目标） -

C:\tools\jasperreports-5.0.1\test>ant -Dmain-class=com.tutorialspoint.JasperReportFill
Buildfile: C:\tools\jasperreports-5.0.1\test\build.xml

clean-sample:
   [delete] Deleting directory C:\tools\jasperreports-5.0.1\test\classes
   [delete] Deleting: C:\tools\jasperreports-5.0.1\test\jasper_report_template.jasper
   [delete] Deleting: C:\tools\jasperreports-5.0.1\test\jasper_report_template.jrprint

compile:
   [mkdir] Created dir: C:\tools\jasperreports-5.0.1\test\classes
   [javac] C:\tools\jasperreports-5.0.1\test\baseBuild.xml:28: warning:
   'includeantruntime' was not set, defaulting to build.sysclasspath=last;
   set to false for repeatable builds
   [javac] Compiling 7 source files to C:\tools\jasperreports-5.0.1\test\classes

compilereportdesing:
   [jrc] Compiling 1 report design files.
   [jrc] log4j:WARN No appenders could be found for logger
   (net.sf.jasperreports.engine.xml.JRXmlDigesterFactory).
   [jrc] log4j:WARN Please initialize the log4j system properly.
   [jrc] log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig
   for more info.
   [jrc] File : C:\tools\jasperreports-5.0.1\test\jasper_report_template.jrxml ... OK.

run:
   [echo] Runnin class : com.tutorialspoint.JasperReportFill
   [java] log4j:WARN No appenders could be found for logger
   (net.sf.jasperreports.extensions.ExtensionsEnvironment).
   [java] log4j:WARN Please initialize the log4j system properly.

viewFillReport:
   [java] log4j:WARN No appenders could be found for logger
   (net.sf.jasperreports.extensions.ExtensionsEnvironment).
   [java] log4j:WARN Please initialize the log4j system properly.

BUILD SUCCESSFUL
Total time: 18 seconds

由于以上编译，JasperViewer 窗口会如以下屏幕所示打开：