Report+jasperReport客户端打印
核心提示：jasperReport客户端采用 applet，applet和activeX插件的区别大家搜一下，有一堆东西可以借鉴，下载jasperreports-3.0.0，在相应的 sample OR demo（记得不清了）中可以找到jasperReport实现的客户端打印demo，下来就来分析下具体实现。 新建一print.js文件: fun
jasperReport客户端采用 applet，applet和activeX插件的区别大家搜一下，有一堆东西可以借鉴，下载jasperreports-3.0.0，在相应的 sample OR demo（记得不清了）中可以找到jasperReport 实现的客户端打印demo，下来就来分析下具体实现。
新建一print.js文件:
function loadApplet(applet_URL) {
var URL = applet_URL + " /applets/jre-1_5_0_18-windows-i586-p.exe " ;
document.write(' < OBJECT id = " myApplet " name = " myApplet " ');
document.write('classid = " clsid:8AD9C840-044E-11D1-B3E9-00805F499D93 " WIDTH = " 0 " HEIGHT = " 0 " MAYSCRIPT name = " myApplet " ');
document.write('codebase = ' + URL + ' > ');
document.write(' < PARAM NAME = " CODE " VALUE = " org.bulktree.report.print.applet.PrinterApplet " /> ');
document.write(' < PARAM NAME = " CODEBASE " VALUE = " ../applets " /> ');
document.write(' < PARAM NAME = " ARCHIVE " VALUE = " jasperreports-3.0.1-applet.jar " /> ');
document.write(' < PARAM NAME = " type " VALUE = " application/x-java-applet;version=1.5.0 " /> ');
document.write(' < PARAM NAME = " scriptable " VALUE = " false " /> ');
document.write(' < PARAM NAME = " REPORT_URL " VALUE = " ../report.view " > ');
document.write('no support java');
document.write(' < comment > ');
document.write(' < embed type = " application/x-java-applet;version=1.5.0 " ');
document.write('CODE = " org.bulktree.report.print.applet.PrinterApplet " ');
document.write('JAVA_CODEBASE = " applets " ARCHIVE = " jasperreports-3.0.1-applet.jar " ');
document.write('scriptable = false ');
document.write('pluginspage = ' + URL + ' > ');
document.write(' < noembed ></ noembed > ');
document.write(' </ embed > ');
document.write(' </ comment > ');
document.write(' </ OBJECT > ');
}
URL为一个固定的路径，是为了下载/applets/jre-1_5_0_18-windows-i586-p.exe（JRE运行环境）而存在的，也可以使用外网从sun公司网站下载，
REPORT_URL 为applet所要访问的地址，在工程的web.xml配置/report.view如下servlet即可，此servet可接收applet参数，生成jasperPrint对象，并传递到客户端applet中进行打印或者预览。
servlet配置如下：
< servlet >
< servlet-name > ReportServlet </ servlet-name >
< servlet-class > org.bulktree.report.print.applet.ReportServlet </ servlet-class >
</ servlet >
< servlet-mapping >
< servlet-name > ReportServlet </ servlet-name >
< url-pattern > /report.view </ url-pattern >
</ servlet-mapping >
ReportServlet核心代码就是根据业务找到对应的模板文件填充数据生成jasperPrint对象，产生的jasperPrint对象以对象流的形式发送给客户端，核心代码如下：
// 生成jasperPrint对象
JasperPrint jasperPrint = JasperFillManager.fillReport(jasperReport,
mapParam, new JREmptyDataSource());
// 组装流
response.setContentType( " application/octet-stream " );
response.setBufferSize( 8986000 );
ServletOutputStream outStream = response.getOutputStream();
ObjectOutputStream oos = new ObjectOutputStream(outStream);
oos.writeObject(jasperPrint);
当然，客户端的applet使用如下：
/*
* applet与Servlet交互 URL传递页面传来的参数请求服务器Servlet
* 把applet传递的参数追加到servlet中 2008-10-14 laoshulin
*/
url = new URL(getCodeBase(), requestUrl + " ?printView=true "
+ paraStr);
if (url == null ) {
JOptionPane.showMessageDialog( this ,
" Source URL not specified " );
} else {
InputStream in = url.openStream();
ObjectInputStream objIn = new ObjectInputStream(in);
Object obj = objIn.readObject();
if (obj instanceof JasperPrint) {
} else {
JOptionPane.showMessageDialog( this , obj.toString());
return ;
}
if (jasperPrint == null ) {
// 根据Servlet返回的URL（ObjectStream）产生JasperPrint对象
jasperPrint = (JasperPrint) obj;
}
// 拦截出现空报表问题
if (jasperPrint != null
&& jasperPrint.getPages().size() > 0 ) {
/*
* 调用JasperReport.jar中JasperViewer绘制报表Frame
* JasperViewer继承自JFrame，采用setDefaultCloseOperation响应关闭窗口事件
*/
ViewerFrame viewerFrame = new ViewerFrame( this
.getAppletContext(), jasperPrint,isShowPrintButton);
viewerFrame.setVisible( true );
// viewerFrame.show();
// JasperViewer viewer = new
// JasperViewer(jasperPrint);
// viewer.setVisible(true);
// viewer.setDefaultCloseOperation(javax.swing.WindowConstants.DISPOSE_ON_CLOSE);
// 如果请求为空弹出对话框予以提示
} else {
JOptionPane
.showMessageDialog( this ,
" Please check Your Report SQL! It resulted in empty Report! " );
return ;
}
}
其中requestUrl为applet配置中的REPORT_URL，现实中可以采用此种方式传递参数到applet中，下篇文章会介绍更合适 的业务数据传递，?printView=true表示，传递printView参数对应的值为true，用来预览使用。剩下的工作就是怎么按照自己的要求 打印和预览了。
jasperReport为我们提供了打印和预览现成的方法：
// 打印报表
JasperPrintManager
.printReport(print, false );
/* 预览报表
* 调用JasperReport.jar中JasperViewer绘制报表Frame
* JasperViewer继承自JFrame，采用setDefaultCloseOperation响应关闭窗口事件
*/
ViewerFrame viewerFrame = new ViewerFrame( this
.getAppletContext(), jasperPrint);
viewerFrame.setVisible( true );