iReport+jasperReport之scriptlet

           转载自http://www.blogjava.net/bulktree/archive/2008/12/17/246786.html

             提起scriptlet就不能不联想到它的强大功能，jasperReport也是支持scriptlet的哦，先分析一下JasperReport的API吧！
在填充报表时scriplet是一个非常有力的工具，JRAbstractScriptlet.java位于net.sf.jasperreports.engine包下是一个抽象
类


beforeReportInit() ，afterReportInit() ，beforePageInit()，afterPageInit(), beforeColumnInit(), afterColumnInit() ,beforeGroupInit(String groupName),afterGroupInit(String groupName) 
看看这些名字就知道你能完成那些功能，这几个方法是要求我们实现的，jasperReport给我们提供了一个实现类JRDefaultScriptlet.java，默认的空实现了上面几个方法，它只是很便利的为我们提供了所需的八个方法的空实现。我们写自己的scriptlet时需要继承JRDefaultScriptlet.java这个类实现自己的相应的功能即可。
 先来看一个简单的例子：
先看看模板文件的处理：
新建时填写的这个类是下面我们要介绍的继承自JRDefaultScriptlet.java类，也就是在模板文件中我们要加上如下代码

scriptletClass="org.bulktree.ireport.scriptlet.ScriptletReportDemo"

完整的模板文件如下：scriptletDemo.jrxml

<? xml version="1.0" encoding="UTF-8"   ?>
<!--  Created with iReport - A designer for JasperReports  -->
<! DOCTYPE jasperReport PUBLIC "//JasperReports//DTD Report Design//EN" "http://jasperreports.sourceforge.net/dtds/jasperreport.dtd" >
< jasperReport
          name ="scriptletDemo"
         columnCount ="1"
         printOrder ="Vertical"
         orientation ="Portrait"
         pageWidth ="595"
         pageHeight ="842"
         columnWidth ="535"
         columnSpacing ="0"
         leftMargin ="30"
         rightMargin ="30"
         topMargin ="20"
         bottomMargin ="20"
         whenNoDataType ="NoPages"
         scriptletClass ="org.bulktree.ireport.scriptlet.ScriptletReportDemo"
         isTitleNewPage ="false"
         isSummaryNewPage ="false" >
     < property  name ="ireport.scriptlethandling"  value ="2"   />
     < property  name ="ireport.encoding"  value ="UTF-8"   />
     < import  value ="java.util.*"   />
     < import  value ="net.sf.jasperreports.engine.*"   />
     < import  value ="net.sf.jasperreports.engine.data.*"   />

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

         < background >
             < band  height ="0"   isSplitAllowed ="true"   >
             </ band >
         </ background >
         < title >
             < band  height ="20"   isSplitAllowed ="true"   >
                 < textField  isStretchWithOverflow ="false"  isBlankWhenNull ="false"  evaluationTime ="Now"  hyperlinkType ="None"   hyperlinkTarget ="Self"   >
                     < reportElement
                         mode ="Opaque"
                        x ="193"
                        y ="0"
                        width ="134"
                        height ="18"
                        backcolor ="#FFCC33"
                        key ="textField" />
                     < box ></ box >
                     < textElement  textAlignment ="Center"  verticalAlignment ="Middle" >
                         < font  pdfFontName ="Helvetica-Bold"  size ="12"  isBold ="true" />
                     </ textElement >
                 < textFieldExpression    class ="java.lang.String" > <![CDATA[ $P{ReportTitle} ]]> </ textFieldExpression >
                 </ textField >
             </ band >
         </ title >
         < pageHeader >
             < band  height ="0"   isSplitAllowed ="true"   >
             </ band >
         </ pageHeader >
         < columnHeader >
             < band  height ="0"   isSplitAllowed ="true"   >
             </ band >
         </ columnHeader >
         < detail >
             < band  height ="264"   isSplitAllowed ="true"   >
                 < textField  isStretchWithOverflow ="false"  isBlankWhenNull ="false"  evaluationTime ="Now"  hyperlinkType ="None"   hyperlinkTarget ="Self"   >
                     < reportElement
                         x ="85"
                        y ="20"
                        width ="329"
                        height ="61"
                        forecolor ="#FF0099"
                        key ="textField-1" />
                     < box ></ box >
                     < textElement  textAlignment ="Center"  verticalAlignment ="Middle" >
                         < font  pdfFontName ="Helvetica-Bold"  size ="20"  isBold ="true" />
                     </ textElement >
                 < textFieldExpression    class ="java.lang.String" > <![CDATA[ $P{REPORT_SCRIPTLET}.showInfor() ]]> </ textFieldExpression >
                 </ textField >
             </ band >
         </ detail >
         < columnFooter >
             < band  height ="0"   isSplitAllowed ="true"   >
             </ band >
         </ columnFooter >
         < pageFooter >
             < band  height ="0"   isSplitAllowed ="true"   >
             </ band >
         </ pageFooter >
         < summary >
             < band  height ="50"   isSplitAllowed ="true"   >
             </ band >
         </ summary >
</ jasperReport >

下来看看怎么实现我们自己的scriplet

ScriptletReportDemo.java

package  org.bulktree.ireport.scriptlet;

import  net.sf.jasperreports.engine.JRDefaultScriptlet;
import  net.sf.jasperreports.engine.JRScriptletException;

/**
 * 
 * @author bulktree Email: [email protected]
 * @Nov 26, 2008
 */
public   class  ScriptletReportDemo  extends  JRDefaultScriptlet  {

    @Override
    public void afterColumnInit() throws JRScriptletException {
        System.out.println("**************************************afterColumnInit()**************************************");
    }

    @Override
    public void afterDetailEval() throws JRScriptletException {
        System.out.println("**************************************afterDetailEval()**************************************");
    }

    @Override
    public void afterGroupInit(String groupName) throws JRScriptletException {
        System.out.println("**************************************afterDetailEval()**************************************");
    }

    @Override
    public void afterPageInit() throws JRScriptletException {
        System.out.println("**************************************afterPageInit()**************************************");
    }

    @Override
    public void afterReportInit() throws JRScriptletException {
        System.out.println("**************************************afterReportInit() begin**************************************");
        
        String str = (String) this.getParameterValue("ReportTitle");
        System.out.println("report title=====>>>>"+str);
        
        str += str.subSequence(0, str.length()-2);
        this.setParameterValue("ReportTitle", str);
        System.out.println("**************************************afterReportInit() end**************************************");
    }

    @Override
    public void beforeColumnInit() throws JRScriptletException {
        System.out.println("**************************************beforeColumnInit()**************************************");
    }

    @Override
    public void beforeDetailEval() throws JRScriptletException {
        System.out.println("**************************************beforeDetailEval()**************************************");
    }

    @Override
    public void beforeGroupInit(String groupName) throws JRScriptletException {
        System.out.println("**************************************beforeGroupInit()**************************************");
    }

    @Override
    public void beforePageInit() throws JRScriptletException {
        System.out.println("**************************************beforePageInit()**************************************");
    }

    @Override
    public void beforeReportInit() throws JRScriptletException {
        System.out.println("**************************************beforeReportInit()**************************************");
    }

    public String showInfor() throws JRScriptletException {
        return "the is scriptlet scriptlet scriptlet the,sscriptlet report the is ascriptlet report this is a scriptlet report this is a scriptlet report";
    }
    
}

这段代码最后一个方法是我们自己的加的，用来在报表上显示一段文本。我们知道对于一个Field、Parameter、Variable，JasperReport分别采用$F{FieldName}、$P{Parametername}、$V{VariableName}来引用，而如果要引用ScriptletReportDemo.java类的showInfor()返回字符串显示在报表上，看看这个就知道了

在afterReportInit方法中我们把parameter字段取出来前后添上五个*号再set进去
    下来写一个test类测试一下：

package  org.bulktree.ireport.scriptlet;

import  java.io.File;
import  java.io.FileInputStream;
import  java.io.InputStream;
import  java.util.HashMap;

import  net.sf.jasperreports.engine.JREmptyDataSource;
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  net.sf.jasperreports.view.JasperViewer;

/**
 * 
 * @author bulktree Email: [email protected]
 * @Nov 27, 2008
 */
public   class  ScriptletTestMain  {

    public static void main(String[] args) {
        String path = "D:/workspace/scriptletDemo.jrxml";

        File file = new File(path);
        InputStream in;
        try {

            HashMap parameters = new HashMap();
            parameters.put("ReportTitle", "LAOSHULIN");
            in = new FileInputStream(file);
            JasperReport jasperReport = JasperCompileManager.compileReport(in);
            JasperPrint jasperPrint = JasperFillManager.fillReport(jasperReport,
                    parameters, new JREmptyDataSource());
            JasperViewer viewer = new JasperViewer(jasperPrint);
            viewer.setVisible(true);

        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

    }
}

效果不错吧：

getParameterValue、setParameterValue方法可以操作Parameter,Field/Variable该怎么set呢？
    看看 JRAbstractScriptlet.java类的这个方法：

public   void  setData(
        Map parsm,
        Map fldsm,
        Map varsm,
        JRFillGroup[] grps
        )
     {
        parametersMap = parsm;
        fieldsMap = fldsm;
        variablesMap = varsm;
        groups = grps;
    }

        似乎有点意思，我们可以通过这个方法把我们期望的数据组装成Map然后set进去，可是要只针对个别字段怎么处理呢，调用此方法似乎不太合常理，仔细查看API却没有实际能调用的API吧！这个似乎不太合乎，仔细看看确实没有调用的，至少目前我还是没有发现，怎么办 自己写吧！
    设置Field方法：

public   void  setFieldValue(String fieldName, Object value)  throws  JRScriptletException
     {
        JRFillField field = (JRFillField)this.fieldsMap.get(fieldName);
        if (field == null)
        {
            throw new JRScriptletException("FieldName not found : " + fieldName);
        }
        
        field.setValue(value);
    }

    设置Variable方法：

public   void  setVariableValue(String variableName, Object value)  throws  JRScriptletException
     {
        JRFillVariable variable = (JRFillVariable)this.variablesMap.get(variableName);
        if (variable == null)
        {
            throw new JRScriptletException("Variable not found : " + variableName);
        }
        
        if (value != null && !variable.getValueClass().isInstance(value) )
        {
            throw new JRScriptletException("Incompatible value assigned to variable " + variableName + ". Expected " + variable.getValueClassName() + ".");
        }
        
        variable.setValue(value);
    }

    OK！这样我们就可以针对报表上的每一个字段处理了，测试通过 代码就不贴了哦,写上篇的时候忘记这两个方法是我自己加的，查看API时才发现所以来了个续