风中叶之struts2学习笔记四
1， 进行文件上传时，必须将表单的method属性设置为post，将enctype属性设置为multipart/form-data。
2， http://apache.etoak.com//commons/fileupload/binaries/commons-fileupload-1.2.2-bin.zip：文件上传组件到apache官网下的顶级项目commons的子项目FileUpload去下载。FileUpload依赖于commons-io，因此还要下载它。我们只需要将commons-fileupload-1.2.2.jar，commons-io-2.4.jar加入到项目的/WebRoot/WEB-INF/lib目录下。
3， struts2实现文件上传，实际上是两步完成的
1） 首先将客户端上传的文件保存到struts.multipart.saveDir键所指定的目录中，如果该键对应的目录不存在，那么就保存到javax.servlet.context.tempdir环境变量所指定的目录中；
2） Action中所定义的File类型的成员变量实际上指向的是临时目录的临时文件，然后在服务器端通过IO的方式将临时文件写入到指定服务器目录中。
文件上传：
4， 一个页面上传多个文件
5， Struts2默认最大上传文件大小是2M，我们可以在src目录下新建一个名为struts.properties的文件覆盖struts2-core-2.3.4.jar/org.apache.struts2/default.properties文件中的相关属性值。
文件大小处理：在struts.properties中设置struts.multipart.maxSize=A A设置的尽量大一些，这样上传就不会出错，然后在程序中进行判断处理。
也可以在struts.xml中以常量的形式指定相关的属性值。
6， 文件下载
7，文件下载2
8， struts2可以使用struts2-convention-plugin-2.2.1.1.jar插件实现基于注解的配置
9， 异步处理请求返回XML，需要用到dom4j.jar struts2整合jquery
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme() + "://"
+ request.getServerName() + ":" + request.getServerPort()
+ path + "/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>My JSP 'getXML.jsp' starting page</title>
<script type="text/javascript" src="scripts/jquery-1.4.4.js"></script>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
<script type="text/javascript">
function getInfo() {
$
.post(
"getXMLAction.action",
{
name : $("#name").val()
},
function(returnedData, status) {
var id = $(returnedData).find("id").text();
var name = $(returnedData).find("name").text();
var age = $(returnedData).find("age").text();
var address = $(returnedData).find("address")
.text();
var html = "<table width='60%' border='1' align='center'>__tag_39$60_<th>id__tag_39$70_<th>name__tag_39$83_<th>age__tag_39$95_<th>address__tag_39$111_<tr align='center'>__tag_39$135_"
+ id
+ "__tag_39$149_<td>"
+ name
+ "__tag_39$170_<td>"
+ age
+ "__tag_39$190_<td>"
+ address
+ "__tag_39$214_</tr>__tag_39$224_";
$("#theBody
</script>
</head>
<body id="theBody">
<select id="name">
<option value="zhangsan">
zhangsan
</option>
<option value="lisi">
lisi
</option>
</select>
<input type="button" value="get information" onclick=
getInfo();;
>
</body>
</html>
GetXMLAction.java
package com.shengsiyuan.action.xml;
import java.io.PrintWriter;
import javax.servlet.http.HttpServletResponse;
import org.apache.struts2.ServletActionContext;
import org.dom4j.Document;
import org.dom4j.DocumentHelper;
import org.dom4j.Element;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.XMLWriter;
import com.opensymphony.xwork2.ActionSupport;
public class GetXMLAction extends ActionSupport
{
private String name;
public String getName()
{
return name;
}
public void setName(String name)
{
this.name = name;
}
@Override
public String execute() throws Exception
{
//zhang san
People people1 = new People();
people1.setId(1);
people1.setName("zhangsan");
people1.setAge(30);
people1.setAddress("beijing");
People people2 = new People();
people2.setId(2);
people2.setName("lisi");
people2.setAge(50);
people2.setAddress("tianjin");
Document document = DocumentHelper.createDocument();
Element rootElement = document.addElement("persons");
rootElement.addComment("This is comment!!");
Element e = rootElement.addElement("person");
Element idElement = e.addElement("id");
Element nameElement = e.addElement("name");
Element ageElement = e.addElement("age");
Element addressElement = e.addElement("address");
if("zhangsan".equals(name))
{
idElement.setText(people1.getId() + "");
nameElement.setText(people1.getName());
ageElement.setText(people1.getAge() + "");
addressElement.setText(people1.getAddress());
}
else
{
idElement.setText(people2.getId() + "");
nameElement.setText(people2.getName());
ageElement.setText(people2.getAge() + "");
addressElement.setText(people2.getAddress());
}
HttpServletResponse response = ServletActionContext.getResponse();
response.setContentType("text/xml; charset=utf-8");
response.setHeader("cache-control", "no-cache");
PrintWriter out = response.getWriter();
OutputFormat format = OutputFormat.createPrettyPrint();
format.setEncoding("utf-8");
XMLWriter writer = new XMLWriter(out, format);
writer.write(document);
out.flush();
out.close();
return null;
}
}
struts.xml
<?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="struts2_ajax" extends="json-default">
<action name="getXMLAction" class="com.shengsiyuan.action.xml.GetXMLAction">
</action>
<action name="getJsonAction" class="com.shengsiyuan.action.json.GetJsonAction">
</action>
<action name="getJsonAction2" class="com.shengsiyuan.action.json.GetJsonAction2">
<result name="success" type="json">
<param name="excludeProperties">address</param>
</result>
</action>
</package>
</struts>
10， 异步处理请求返回JSON，需要用到json.jar，下面列出的代码是与xml不同的地方。
Struts2提供了struts2-json-plugin-2.3.4.jar插件，我们可以以另外的方式处理
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>My JSP 'json.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
<script type="text/javascript" src="scripts/jquery-1.4.4.js"></script>
<script type="text/javascript">
$(function()
{
$("#button1").click(function()
{
$.post("getJsonAction2.action",{name: $("#name").val()},
function(returnedData, status)
{
var people = returnedData;
var id = people.id;
var name = people.name;
var age = people.myAge;
var address = people.address;
var html = "<table width='60%' border='1' align='center'><tr><th>id</th><th>name</th><th>age</th><th>address</th><tr align='center'><td>" + id + "</td><td>" + name + "</td><td>" + age + "</td><td>" + address + "</td></tr></table>";
$("#theBody table:eq(0)").remove();
$("#theBody").append(html);
});
});
});
</script>
</head>
<body id="theBody">
<select id="name">
<option value="zhangsan">zhangsan</option>
<option value="lisi">lisi</option>
</select>
<input type="button" value="get json content from server" id="button1">
</body>
</html>
GetJsonAction.java
package com.shengsiyuan.action.json;
import java.io.PrintWriter;
import javax.servlet.http.HttpServletResponse;
import org.apache.struts2.ServletActionContext;
import com.google.gson.Gson;
import com.opensymphony.xwork2.ActionSupport;
import com.shengsiyuan.action.xml.People;
public class GetJsonAction extends ActionSupport
{
private String name;
public String getName()
{
return name;
}
public void setName(String name)
{
this.name = name;
}
@Override
public String execute() throws Exception
{
People people = new People();
people.setId(1);
people.setName(name);
people.setAge(30);
people.setAddress("beijing");
Gson gson = new Gson();
String result = gson.toJson(people);
HttpServletResponse response = ServletActionContext.getResponse();
response.setContentType("application/json; charset=utf-8");
response.setHeader("cache-control", "no-cache");
PrintWriter out = response.getWriter();
out.print(result);
out.flush();
out.close();
return null;
}
}
GetJsonAction2.java
package com.shengsiyuan.action.json;
import org.apache.struts2.json.annotations.JSON;
import com.opensymphony.xwork2.ActionSupport;
public class GetJsonAction2 extends ActionSupport
{
private String name;
private int id;
private int age;
private String address;
public String getName()
{
return name;
}
public void setName(String name)
{
this.name = name;
}
public int getId()
{
return id;
}
public void setId(int id)
{
this.id = id;
}
@JSON(name="myAge")
public int getAge()
{
return age;
}
public void setAge(int age)
{
this.age = age;
}
public String getAddress()
{
return address;
}
public void setAddress(String address)
{
this.address = address;
}
@Override
public String execute() throws Exception
{
this.id = 1;
this.age = 30;
this.address = "beijing";
return SUCCESS;
}
}
struts.xml
<?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="struts2_ajax" extends="json-default">
<action name="getXMLAction" class="com.shengsiyuan.action.xml.GetXMLAction">
</action>
<action name="getJsonAction" class="com.shengsiyuan.action.json.GetJsonAction">
</action>
<action name="getJsonAction2" class="com.shengsiyuan.action.json.GetJsonAction2">
<result name="success" type="json">
<param name="excludeProperties">address</param>
</result>
</action>
</package>
</struts>