我有index.jsp，其中我有一个链接，点击该链接，该页面特定的操作被调用。现在点击此链接，我需要显示一个已填充多选列表的页面以及少量输入文本字段，在我填充TransactionBean的操作的构造函数中，它将与下一页上的字段绑定，即transactionData.jsp。
使用填充的多选列表正确显示transactionData.jsp页面。现在，用户可以从多选列表中选择值，并可以在文本字段中输入日期，然后单击单击按钮，以显示条形图。
单击Click按钮，我正在调用另一个ActionBean作为其属性的操作。在此操作的execute方法中，我尝试使用getter访问transactionbean，但它给了我NullPointerException。我知道，如果我们提交一个包含bean字段的页面，那么在调用action时，bean会通过拦截器自动实例化，但似乎这里的东西不正确。
的index.jsp
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<%@ taglib prefix="s" uri="/struts-tags"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<title>Hello World</title>
</head>
<body>
<s:form action="displayAction.action">
<h1>Hello World</h1>
<a href="<s:url action="displayAction.action"/>">Transaction Chart</a>
</s:form>
</body>
</html>
DisplayAction.java
package com.tutorialspoint.struts2;
import java.util.ArrayList;
import java.util.List;
import com.opensymphony.xwork2.ActionSupport;
public class DisplayAction extends ActionSupport {
TransactionBean transactionBean;
public TransactionBean getTransactionBean() {
return transactionBean;
}
public void setTransactionBean(TransactionBean transactionBean) {
this.transactionBean = transactionBean;
}
public String execute() {
return SUCCESS;
}
public DisplayAction() {
System.out.println("Inside Constructor");
List<String> leftChannelsList = new ArrayList<String>();
leftChannelsList.add("Channel1");
leftChannelsList.add("Channel2");
//TransactionBean transactionBean = new TransactionBean();
setTransactionBean(new TransactionBean());
getTransactionBean().setLeftChannelsList(leftChannelsList);
//Transaction Type Dta
List<String> leftTransTypesList = new ArrayList<String>();
leftTransTypesList.add("TransType1");
leftTransTypesList.add("TransType2");
getTransactionBean().setLeftTransTypesList(leftTransTypesList);
}
}
transactionData.jsp
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<%@ taglib prefix="s" uri="/struts-tags"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<s:head theme="ajax" debug="true"/>
<title>Hello World</title>
</head>
<body bgcolor="grey">
<s:form action="displayChart.action">
<s:datetimepicker label="Select From" name="transactionBean.fromDate" displayFormat="MM-dd-yy" required="true" /> <s:datetimepicker label="Select To" name="transactionBean.toDate" displayFormat="MM-dd-yy" required="true" />
<s:optiontransferselect
label="Channels"
name="transactionBean.leftChannels"
leftTitle="Unselected Channels"
rightTitle="Selected Channels"
list="transactionBean.leftChannelsList"
multiple="true"
headerKey="-1"
doubleList="transactionBean.rightChannelsList"
doubleName="transactionBean.rightChannels"
doubleHeaderKey="-1"
doubleHeaderValue="Please Select"/>
<!-- Transaction Types -->
<s:optiontransferselect
label="transaction Types"
name="transactionBean.leftTransTypes"
leftTitle="Unselected Transaction Type"
rightTitle="Selected Transaction Type"
list="transactionBean.leftTransTypesList"
multiple="true"
headerKey="-1"
doubleList="transactionBean.rightTransTypesList"
doubleName="transactionBean.rightTransTypes"
doubleHeaderKey="-1"
doubleHeaderValue="Please Select"/>
<s:submit value="click" align="center"/>
</s:form>
</body>
</html>
JfreeChartAction.java
public class JfreeChartAction extends ActionSupport {
private JFreeChart chart;
private TransactionBean transactionBean;
private TransactionDao transactionDao;
public TransactionDao getTransactionDao() {
return transactionDao;
}
public void setTransactionDao(TransactionDao transactionDao) {
this.transactionDao = transactionDao;
}
public TransactionBean getTransactionBean() {
return transactionBean;
}
public void setTransactionBean(TransactionBean transactionBean) {
this.transactionBean = transactionBean;
}
// This method will get called if we specify <param name="value">chart</param>
public JFreeChart getChart() {
return chart;
}
public void setChart(JFreeChart chart) {
this.chart = chart;
}
public JfreeChartAction() {}
public String execute() throws Exception {
System.out.println("Inside Execute: Start");
System.out.println("From date:" + getTransactionBean().getFromDate());
System.out.println("From date:" + getTransactionBean().getToDate());
System.out.println("leftChannelsList:" + getTransactionBean().getLeftChannelsList());
System.out.println("Left Trans type List" + getTransactionBean().getLeftTransTypesList());
DefaultCategoryDataset dataSet = new DefaultCategoryDataset();
dataSet.setValue(0, "01-04-2014", "Channel1");
dataSet.setValue(15000, "01-04-2014", "Channel2");
dataSet.setValue(9000, "01-05-2014", "Channel1");
dataSet.setValue(1500, "01-05-2014", "Channel2");
dataSet.setValue(10000, "01-06-2014", "Channel1");
dataSet.setValue(8000, "01-06-2014", "Channel2");
chart = ChartFactory.createBarChart(
"Demo Bar Chart", //Chart title
"Mobile Manufacturer", //Domain axis label
"TRANSACTIONS", //Range axis label
dataSet, //Chart Data
PlotOrientation.VERTICAL, // orientation
true, // include legend?
true, // include tooltips?
false // include URLs?
);
chart.setBorderVisible(true);
System.out.println("Inside Execute: End");
return SUCCESS;
}
}
struts.xml中
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE struts PUBLIC
"-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
"http://struts.apache.org/dtds/struts-2.0.dtd">
<struts>
<package name="default" namespace="/" extends="struts-default">
<action name="displayAction"
class="com.tutorialspoint.struts2.DisplayAction"
method="execute">
<result name="success">transactionsData.jsp</result>
</action>
</package>
<package name="defaultJfreeChart" namespace="/" extends="jfreechart-default">
<action name="displayChart"
class="com.tutorialspoint.struts2.JfreeChartAction"
method="execute">
<result name="success" type="chart">
<param name="value">chart</param>
<param name="type">jpeg</param>
<param name="width">600</param>
<param name="height">400</param>
</result>
</action>
</package>
</struts>
TransactionBean.java
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import org.jfree.chart.JFreeChart;
public class TransactionBean {
private Date dateTime;
private Integer volume;
private String leftChannels;
private String rightChannels;
private String toDate;
private String fromDate;
private List<String> leftChannelsList;
private List<String> rightChannelsList;
//Transaction type data
private String leftTransTypes;
private List<String> leftTransTypesList;
private String rightTransTypes;
private List<String> rightTransTypesList;
public Date getDateTime() {
return dateTime;
}
public void setDateTime(Date dateTime) {
this.dateTime = dateTime;
}
public Integer getVolume() {
return volume;
}
public void setVolume(Integer volume) {
this.volume = volume;
}
public TransactionBean(){
//System.out.println("Inside TransactionBean constructor");
}
public String getLeftTransTypes() {
return leftTransTypes;
}
public void setLeftTransTypes(String leftTransTypes) {
this.leftTransTypes = leftTransTypes;
}
public List<String> getLeftTransTypesList() {
return leftTransTypesList;
}
public void setLeftTransTypesList(List<String> leftTransTypesList) {
this.leftTransTypesList = leftTransTypesList;
}
public String getRightTransTypes() {
return rightTransTypes;
}
public void setRightTransTypes(String rightTransTypes) {
this.rightTransTypes = rightTransTypes;
}
public List<String> getRightTransTypesList() {
return rightTransTypesList;
}
public void setRightTransTypesList(List<String> rightTransTypesList) {
this.rightTransTypesList = rightTransTypesList;
}
public String getToDate() {
return toDate;
}
public void setToDate(String toDate) {
this.toDate = toDate;
}
public String getFromDate() {
return fromDate;
}
public void setFromDate(String fromDate) {
this.fromDate = fromDate;
}
public String getLeftChannels() {
return leftChannels;
}
public void setLeftChannels(String leftChannels) {
this.leftChannels = leftChannels;
}
public String getRightChannels() {
return rightChannels;
}
public void setRightChannels(String rightChannels) {
this.rightChannels = rightChannels;
}
public List<String> getRightChannelsList() {
return rightChannelsList;
}
public void setRightChannelsList(List<String> rightChannelsList) {
this.rightChannelsList = rightChannelsList;
}
public List<String> getLeftChannelsList() {
return leftChannelsList;
}
public void setLeftChannelsList(List<String> leftChannelsList) {
this.leftChannelsList = leftChannelsList;
}
}
答案 0 :(得分：0)
你可以告诉我应该使用哪个版本。
始终使用最新版本。目前它是Struts 2.3.16.3 GA。您还可以看到Version Notes和Migration Guide。