Struts 2 拦截器
interceptor(拦截器)是一种可以在请求处理之前或者之后执行的Struts 2组件。拦截器是Struts 2的重要特性，Struts 2框架绝大多数功能都是通过拦截器来完成的。
1.拦截器类:
public class MyTimerInterceptor extends AbstractInterceptor {
@Override
public String intercept(ActionInvocation invocation) throws Exception {
// 1。执行Action之前的工作:获取开始执行时间
long startTime = System.currentTimeMillis();
System.out.println("执行Action之前的工作，开始时间:" + startTime);
// 执行后续拦截器或Action
String result = invocation.invoke();
// 3.执行Action之后的工作，计算并输出执行时间
long endTime = System.currentTimeMillis();
long execTime = endTime - startTime;
System.out.println("ִ执行Action后的工作,结束时间" + endTime);
System.out.println("总共时间:" + execTime);
return result;
}
}
拦截器的配置
通过<interceptor/》元素定义拦截器
通过<interceptot-ref/》元素使用拦截器
<package name="default" namespace="/" extends="struts-default">
<!-- 拦截器 -->
<interceptors>
<!-- action的执行用时 -->
<interceptor name="myTimer" class="util.MyTimerInterceptor" />
</interceptors>
<action name="login" class="userAction" method="login">
<result name="success">main.jsp</result>
<result name="error">login.jsp</result>
<result name="input">login.jsp</result>
<interceptor-ref name="myTimer"></interceptor-ref>
<interceptor-ref name="defaultStack"></interceptor-ref>
</action>
定义拦截器栈
<interceptors>
<!-- action的执行用时 -->
<interceptor name="myTimer" class="util.MyTimerInterceptor" />
<interceptor name="myAuthorization" class="util.AuthorizationInterceptot" />
<interceptor-stack name="myStack">
<interceptor-ref name="myAuthorization" />
<interceptor-ref name="defaultStack" />
</interceptor-stack>
</interceptors>
自定义拦截器
权限验证检查拦截器
public class AuthorizationInterceptot extends AbstractInterceptor {
public String intercept(ActionInvocation invocation) {
Map session = invocation.getInvocationContext().getSession();
User user = (User) session.get("USER");
if (user == null) {
return Action.SUCCESS;
} else {
return Action.ERROR;
}
}
}
配置文件
<package name="default" namespace="/" extends="struts-default">
<!-- 拦截器 -->
<interceptors>
<!-- action的执行用时 -->
<!-- 定义权限验证拦截器 -->
<interceptor name="myAuthorization" class="util.AuthorizationInterceptot" />
<interceptor-stack name="myStack">
<interceptor-ref name="myAuthorization" />
<interceptor-ref name="defaultStack" />
</interceptor-stack>
</interceptors>
<!-- 定义默认拦截器 -->
<default-interceptor-ref name="myStack" />
<default-action-ref name="defaultAction" />
<!-- 定义全局结果 -->
<global-results>
<result name="login" type="redirect">
/login.jsp
</result>
</global-results>
</package>
注意：指定默认拦截器后，action中可省略拦截器的引用
文件上传
准备commons-fileupload-x.x.x.jar和commons-io-x.x.x.jar
1.jsp中
<s:form action="upload.action" enctype="multipart/form-data"
method="post">
<s:textfield name="title" lable="标题" />
<br />
<s:file name="upload" lable="选择文件" />
<br />
<s:submit name="submit" value="上传文件" />
</s:form>
2.文件上传的action
public class UploadAction extends ActionSupport {
private File upload; // 获取提交的文件
private String uploadContentType; // 封装上传文件的类型
private String uploadFileName; // 服装上传文件名称
private String savePath; // 获取文件的路径
public String execute() throws Exception {
byte[] buffer = new byte[1024];
//读取文件
FileInputStream fis = new FileInputStream(getUpload());
//保存问津
FileOutputStream fos = new FileOutputStream(getSavePath() + "\\"+ this.getUploadFileName());
int length = fis.read(buffer);
while (length > 0) {
fos.write(buffer, 0, length);
length = fis.read(buffer);
}
fis.close();
fos.flush();
fos.close();
}
return SUCCESS;
}
public String getSavePath() {
return ServletActionContext.getServletContext().getRealPath(savePath);
}
}
3.Strut.xml
<action name="upload" class="action.UploadAction">
<param name="savePath">/upload</param>
<result name="success">/upload_success.jsp</result>
</action>
4.success.jsp
你所上传的文件是:
<s:property value="uploadFileName" />
文件类型:
<s:property value="uploadContentType" />
多文件上传
action
private File[] upload; // 获取提交的文件
private String[] uploadContentType; // 封装上传文件的类型
private String[] uploadFileName; // 服装上传文件名称
private String savePath; // 获取文件的路径
public String execute() throws Exception {
byte[] buffer = new byte[1024];
for (int i = 0; i < upload.length; i++) {
FileInputStream fis = new FileInputStream(getUpload()[i]);
FileOutputStream fos = new FileOutputStream(getSavePath() + "\\"
+ this.getUploadFileName()[i]);
int length = fis.read(buffer);
while (length > 0) {
fos.write(buffer, 0, length);
length = fis.read(buffer);
}
fis.close();
fos.flush();
fos.close();
}
return SUCCESS;
}
public String getSavePath() {
return ServletActionContext.getServletContext().getRealPath(savePath);
}
文件下载
1.jsp
<a href="download.action?fileName=334.jpg">点击下载</a>
2.struts.xml
<action name="download" class="action.FileDownAction">
<param name="inputPath">/upload</param>
<!-- <result name="success">/upload_success.jsp</result> -->
<result name="success" type="stream">
<param name="contentType">application/octet-stream</param>
<param name="inputName">inputStream</param>
<param name="contentDisposition">
attachment;filename="${fileName}"
</param>
<param name="bufferSize">4096</param>
</result>
</action>
3.action
private String inputPath; // 读取下载文件的目录
private String fileName; // 下载文件的文件名
@SuppressWarnings("unused")
private InputStream inputStream; // 读取下载文件的输入流
private String conetntType; // 下载文件的类型
public InputStream getInputStream() throws FileNotFoundException {
String path = ServletActionContext.getServletContext().getRealPath(
inputPath);
return new BufferedInputStream(new FileInputStream(path + "\\"
+ fileName));
}
public String execute() throws Exception {
return SUCCESS;
}
stream结果类型的配置参数
| 名称 | 作用 |
|---|---|
| contentType | 设置发送到浏览器的MIME类型 |
| cpntentLengh | 设置文件的大小 |
| content | 设置响应的HTTP头信息中的Content-Disposition参数的值 |
| inputName | 指定Action中提供inputStream类型的属性名称 |
| bufferSize | 设置读取下载文件时的缓冲区大小 |
contentType文件类型
| 文件类型 | contentType设置 |
|---|---|
| Word | application/msword |
| Excel | application/vnd.ms-excel |
| PPT | application/vnd.ms-powerpoint |
| 图片 | image/gif,image/bmp,image/jpeg |
| 文本文件 | text/plain |
| HTML网页 | text/HTML |
| 任意的二进制数据 | application/octet-stream |