在上篇文章中，已經用iReport製作好報表的template，這篇文章就要介紹在Servlet中使用JasperReport的jar檔產生報表。
首先我們需要為我們之前建立的JasperReportExample專案import需要用到的jar檔如下，我們可以去Maven的官網下載jar檔，下列的版本僅供各位參考，不同的java版本會要不同的jar版本：
bcprov-jdk15on-1.46.jar
commons-beanutils-1.9.3.jar
commons-collections-3.2.1.jar
commons-digester-2.1.jar
commons-logging-1.2.jar
iText-2.1.7.js2.jar
jasperreports-5.6.1.jar
kaiu.jar （在第一篇中用iReport產出的字型jar檔）
mysql-connector-java-5.1.38.jar
poi-3.10.1.jar
Step 1.接著就是進入程式的部分，首先我們先製作前端的JSP頁面，我們需要有兩個DatePicker欄位讓使用者選擇要查詢的生日起迄日，還有一個報表類型的Select讓使用者可以選擇要產生PDF或是Excel的報表，我們就在專案的/JasperReportExample/WebContent/html/pages路徑下新增一個index.jsp
inway0407
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<script src="<%=request.getContextPath()%>/html/js/jquery-3.3.1.min.js" type="text/javascript"></script>
<script src="<%=request.getContextPath()%>/html/js/jquery-ui.min.js" type="text/javascript"></script>
<link rel="stylesheet" href="<%=request.getContextPath()%>/html/css/jquery-ui.min.css">
<script>
$( function() {
$( "#startDate" ).datepicker({dateFormat : "yy-mm-dd"});
$( "#endDate" ).datepicker({dateFormat : "yy-mm-dd"});
} );
</script>
<title>ReportDownload</title>
</head>
<body>
<form method="Post" action="/JasperReportExample/ReportDownload">
<p>起始時間：<input type="text" id="startDate" name="startDate" autocomplete="off"></p>
<p>結束時間：<input type="text" id="endDate" name="endDate" autocomplete="off"></p>
<p>報表類型：
<select name="reportType">
<option value="PDF">PDF</option>
<option value="Excel">Excel</option>
</select>
</p>
<input type="submit" value="下載">
</form>
</body>
</html>
Step 2.接著我們要在路徑/JasperReportExample/src/com/example/controller為這個JSP新增一個Home.java的controller，讓request進來的時候可以導到我們的index.jsp去。
package com.example.controller;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
@WebServlet("/Home")
public class Home extends HttpServlet {
private static final long serialVersionUID = 1L;
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.getRequestDispatcher("/html/pages/index.jsp").forward(request, response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request, response);
}
}
Step 3.完成後我們就可以先run在tomcat上，並在瀏覽器打上網址http://localhost:8080/JasperReportExample/Home ，就可以看到我們剛剛做的JSP畫面如下。
Step 4.接著我們要在路徑/JasperReportExample/src/com/example/dao做一個PersonDao.java，讓我們可以去DB查詢Person的table，我們這邊用的DB是MySQL，並事先為這個表格塞入一些假資料。
package com.example.dao;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import com.example.model.Person;
public class PersonDao {
public List<Person> getPersonList(String startDate, String endDate){
Connection conn = null;
PreparedStatement ps = null;
List<Person> personList = new ArrayList<Person>();
try {
Class.forName("com.mysql.jdbc.Driver");
conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/new_schema", "yourDBAccount", "yourDBPassword");
String sql =" select * from Person where (Birthday Between ? AND ?) order by Id";
ps = conn.prepareStatement(sql);
ps.setString(1, startDate);
ps.setString(2, endDate);
ResultSet rs = ps.executeQuery();
while(rs.next()){
Person person = new Person();
person.setId(rs.getInt("Id"));
person.setName(rs.getString("Name"));
person.setAge(rs.getString("Age"));
person.setPhone(rs.getString("Phone"));
person.setEmail(rs.getString("Email"));
person.setBirthday(rs.getString("Birthday").substring(0, 10));
personList.add(person);
}
} catch (SQLException | ClassNotFoundException e) {
e.printStackTrace();
} finally {
try {
conn.close();
ps.close();
conn = null;
} catch (SQLException e) {
e.printStackTrace();
}
}
return personList;
}
}
Step 5.最後在路徑/JasperReportExample/src/com/example/controller新增一個ReportDownload.java的controller,並在這邊接收前端JSP傳過來的參數，然後用剛剛做的dao去DB查資料，然後再製作報表。
package com.example.controller;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.example.dao.PersonDao;
import com.example.model.Person;
import net.sf.jasperreports.engine.JRAbstractExporter;
import net.sf.jasperreports.engine.JRDataSource;
import net.sf.jasperreports.engine.JREmptyDataSource;
import net.sf.jasperreports.engine.JRException;
import net.sf.jasperreports.engine.JRExporterParameter;
import net.sf.jasperreports.engine.JasperFillManager;
import net.sf.jasperreports.engine.JasperPrint;
import net.sf.jasperreports.engine.JasperReport;
import net.sf.jasperreports.engine.JasperRunManager;
import net.sf.jasperreports.engine.data.JRBeanCollectionDataSource;
import net.sf.jasperreports.engine.export.JRPdfExporter;
import net.sf.jasperreports.engine.export.JRXlsExporter;
import net.sf.jasperreports.engine.util.JRLoader;
@WebServlet("/ReportDownload")
public class ReportDownload extends HttpServlet {
private static final long serialVersionUID = 1L;
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// 前端傳進來的參數
String startDate = request.getParameter("startDate");
String endDate = request.getParameter("endDate");
String reportType = request.getParameter("reportType");
File file = null;
JasperReport jasperReport = null;
JRDataSource dataSource = null;
JRAbstractExporter exporter = null;
byte[] bytes = null;
try {
// 用iReport產出來的jasper檔案路徑
String path = "/Users/greg/Desktop/JasperReportExample.jasper";
file = new File(path);
jasperReport = (JasperReport) JRLoader.loadObject(file);
} catch(JRException e) {
System.err.println(e);
}
// 資料庫查詢資料
PersonDao dao = new PersonDao();
List<Person> personList = dao.getPersonList(startDate, endDate+" 23:59:59");
int size = personList.size();
if(size > 0) {
dataSource = new JRBeanCollectionDataSource(personList);
}else {
dataSource = new JREmptyDataSource();
}
Map parameters=new HashMap();
parameters.put ("searchDate", startDate + "~" + endDate);
if("PDF".equals(reportType)) {
exporter = new JRPdfExporter();
}else if ("Excel".equals(reportType)) {
exporter = new JRXlsExporter();
}
try {
ByteArrayOutputStream oStream = new ByteArrayOutputStream();
JasperPrint jasperPrint = JasperFillManager.fillReport("/Users/greg/Desktop/JasperReportExample.jasper", parameters, dataSource);
exporter.setParameter(JRExporterParameter.JASPER_PRINT, jasperPrint);
exporter.setParameter(JRExporterParameter.OUTPUT_STREAM, oStream);
exporter.exportReport();
bytes = oStream.toByteArray();
oStream.close();
} catch (JRException e) {
e.printStackTrace();
System.err.println(e);
}
if("PDF".equals(reportType)) {
response.setHeader("Content-Disposition","attachment; filename=JasperReportExample.pdf");
response.setContentType("application/pdf");
response.setContentLength(bytes.length);
}else if("Excel".equals(reportType)) {
response.setHeader("Content-Disposition","attachment; filename=JasperReportExample.xls");
response.setContentType("application/vnd.ms-excel");
response.setContentLength(bytes.length);
}
ServletOutputStream ouputStream = response.getOutputStream();
ouputStream.write(bytes, 0, bytes.length);
ouputStream.flush();
ouputStream.close();
}
}
Step 6.到目前我們的程式部份都完成囉，專案的架構如下
Step 7.完成後我們就可以在剛剛的JSP網址選擇日期跟報表類型進行下載，因為這只是個小Demo，所以並沒有對前端的值進行檢查，各位有興趣的話可以自己在前端用JQuery或在後端新增檢查的邏輯。
產出來的PDF報表：
產出來的Excel報表：
這個小專案到這邊就差不多完成囉，其實用iReport製作template還有很多功能可以操作，大家有興趣的話可以製作更複雜的template，製作屬於自己的客製化報表，若是對source code有興趣的話可以參考我的GitHub。
對這篇主題有任何指教的部分也請各位在下方留言，互相交流～
iThome鐵人賽
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