J2ee应用程序结合水晶报表：例程研究

来源：csdn 作者：纸上谈兵出处：巧巧读书 2007-09-06 进入讨论组

访问 http://www.qqread.com/j2ee/w329842.html

报表工厂类创建一个报表实例，用request参数来确定报表类型。这种方法巧妙的把商业逻辑通过一个方法（method）装入单独报表。在ReportFactory子集中，工厂方法对于复合报表来说是一个最好的解决办法－ReportFactory能够代表子集创建一个报表。

package com.ensemsys.twb.presentation.crystal;

import com.crystaldecisions.sdk.occa.report.data.Fields;

import com.crystaldecisions.sdk.occa.report.data.ParameterField;

import com.crystaldecisions.sdk.occa.report.data.ParameterFieldDiscreteValue;

import com.crystaldecisions.sdk.occa.report.data.Values;

import javax.servlet.ServletRequest;

import javax.servlet.jsp.JspException;

import java.sql.Date;

import java.text.DateFormat;

import java.text.ParseException;

import java.text.SimpleDateFormat;

/**

* Provides methods for creating an instance of a Report

* from the parameters in the request.

public class ReportFactory

{

public static final DateFormat FORMAT =

new SimpleDateFormat( "yyyy.MM.dd" );

public static Report newInstance( ServletRequest request )throws JspException

{

String reportType = getParameter( request, ReportParameter.TYPE );

Report report = null;

// For brevity, only the simple report type is shown here

if ( reportType.equals( ReportType.BANKED_TIME_SIMPLE ) )

{

report = newSimpleBankedTimeReport( request );

}else

{

throw new InvalidReportTypeException( reportType );

}

return report;

}

图四：ReportFactory.java 基于form提交的参数创建一个实例

private static Report newSimpleBankedTimeReport( ServletRequest request )

throws JspException

{

Date startDate = getDateParameter( request, ReportParameter.START_DATE );

Date endDate = getDateParameter( request, ReportParameter.END_DATE );

Fields fields = new Fields();

ParameterField prevYearField = newDateField( "Prev Fiscal Year", startDate);

ParameterField reportDateField = newDateField( "Report Date", endDate );

fields.add( prevYearField );

fields.add( reportDateField );

return new Report( "protected/reports/bhr_simple_demo.rpt",

ReportType.BANKED_TIME_SIMPLE, fields );

}

public static ParameterField newDateField( String name, Date date )

{

ParameterField field = new ParameterField();

Values vals = new Values();

ParameterFieldDiscreteValue value = new ParameterFieldDiscreteValue();

field.setName( name );

value.setValue( date );

field.setReportName( "" );

value.setDescription( "" );

vals.add( value );

field.setCurrentValues( vals );

return field;

}

public static Date newDate( String s )

throws InvalidDateStringException

{

java.sql.Date date = null;

try{

date = new java.sql.Date( FORMAT.parse( s ).getTime() );

}

catch ( ParseException e )

{

throw new InvalidDateStringException( e );

}

return date;

}

protected static void assertHasParameter( ServletRequest request,

String name)

{

String parameter = request.getParameter( name );

if ( parameter == null || parameter.equals( "" ) )

{

throw new NoSuchParameterException( name );

}

图四：ReportFactory.java

protected static Date getDateParameter( ServletRequest request, String name )

throws JspException

{

String parameter = getParameter( request, name );

Date date = null;

try{

date = newDate( parameter );

}

catch ( InvalidDateStringException e )

{

throw new JspException( e );

}

return date;

}

protected static String getParameter( ServletRequest request, String name )

{

assertHasParameter( request, name );

return request.getParameter( name );

}

图四：ReportFactory.java

SimpleReportViewerTag.java 呈现报表，这个类使用水晶报表的API来完成画出报表的工作。这个类非常简单――它创建一个CrystalReportViewer实例，设置数据库连接信息和报表需要的参数，最后显示报表。对应的TLD，simplereportviewer.tld，在图六列出。

package com.ensemsys.twb.presentation.crystal;

import com.crystaldecisions.report.web.viewer.CrystalReportViewer;

import

com.crystaldecisions.reports.reportengineinterface.JPEReportSourceFactory;

import com.crystaldecisions.sdk.occa.report.data.ConnectionInfo;

import com.crystaldecisions.sdk.occa.report.data.ConnectionInfos;

import com.crystaldecisions.sdk.occa.report.data.Fields;

import com.crystaldecisions.sdk.occa.report.data.IConnectionInfo;

import com.crystaldecisions.sdk.occa.report.lib.ReportSDKExceptionBase;

import com.crystaldecisions.sdk.occa.report.reportsource.IReportSource;

import com.crystaldecisions.sdk.occa.report.reportsource.IReportSourceFactory2;

import com.ensemsys.twb.ApplicationProperties;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import javax.servlet.jsp.JspException;

import javax.servlet.jsp.tagext.TagSupport;

import java.util.Locale;

图五：SimpleReportViewerTag.java 被执行来显示一个报表。

/**

* Displays a Crystal report.

public class SimpleReportViewerTag extends TagSupport

{

private Report report;

public Report getReport()

{

return report;

}

public void setReport( Report report )

{

this.report = report;

}

public int doEndTag() throws JspException

{

CrystalReportViewer viewer = newViewer( report );

try{

IReportSourceFactory2 rptSrcFactory = new JPEReportSourceFactory();

IReportSource reportSource =

(IReportSource) rptSrcFactory.createReportSource(

report.getReportFileName(), getLocale() );

viewer.setReportSource( reportSource );

viewer.setDatabaseLogonInfos( newDBConnectionInfos() );

viewer.setEnableLogonPrompt( false );

Fields fields = report.getFields();

if ( fields != null )

{

viewer.setParameterFields( fields );

viewer.setEnableParameterPrompt( false );

}

viewer.processHttpRequest(

(HttpServletRequest) pageContext.getRequest(),

(HttpServletResponse) pageContext.getResponse(),

pageContext.getServletConfig().getServletContext(),

pageContext.getOut() );

}

catch ( ReportSDKExceptionBase e )

{

throw new JspException( e );

}

finally

{

if ( viewer != null )

{

viewer.dispose();

}

return EVAL_PAGE;

}

图五：SimpleReportViewerTag.java

private Locale getLocale()

{

// generally you want to change this method

// to return the specific locale that your J2EE

// application is using

return pageContext.getRequest().getLocale();

}

private static ConnectionInfos newDBConnectionInfos()

{

ConnectionInfos infos = new ConnectionInfos();

IConnectionInfo con = new ConnectionInfo();

con.setUserName( ApplicationProperties.getJDBCUser() );

con.setPassword( ApplicationProperties.getJDBCPassword() );

infos.add( con );

return infos;

}

private static CrystalReportViewer newViewer( Report report )

{

CrystalReportViewer viewer = new CrystalReportViewer();

viewer.setName( report.getName() );

// set the viewer formatting and behaviour options

//viewer.setSeparatePages( false );

//viewer.setBestFitPage( true );

// ... and so on

return viewer;

}

图五：SimpleReportViewerTag.java

<?xml version="1.0" encoding="ISO-8859-1" ?>

<!DOCTYPE taglib

PUBLIC "-//Sun Microsystems, Inc.//DTD JSP Tag Library 1.2//EN"

"http://java.sun.com/dtd/web-jsptaglibrary_1_2.dtd">

<tlib-version>1.0</tlib-version>

<jsp-version>1.2</jsp-version>

<short-name>Crystal Viewer Tag Library</short-name>

<description>Display a Crystal Report with paramters</description>

<tag>

<name>viewer</name>

com.ensemsys.twb.presentation.crystal.SimpleReportViewerTag

</tag-class>

<body-content>JSP</body-content>

<name>report</name>

</attribute>

</tag>

</taglib>

图六：simplereportviewer.tld

应为TWB仅仅允许管理者查看报表，TWB现有的接口控制系统控制对报表的访问。将来，TWB可以要求更精细的访问控制－例如，用户可以在有限的条件下查看特定项目的报表。在这个案例中，为了到达这种访问标准，我们使用水晶报表的安全特性。

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J2ee应用程序结合水晶报表：例程研究

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站内频道文章精选

新闻资讯

操作系统

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