Struts2 语法--result type
- result type:
dispatcher,redirect:只能跳转到jsp,html之类的页面,dispatcher属于服务器跳转, redirect属于客户端跳转
chain: 等同于forwardaction,
redirectAction: 客户端跳转到另一个action
还有freemarker,httpheader,stream(下载),volocity(类似freemarker), xslt, plaintext,tiles
<?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>
<constant name="struts.devMode" value="true" />
<package name="resultTypes" namespace="/r" extends="struts-default">
<action name="r1">
<result type="dispatcher">/r1.jsp</result>
</action>
<action name="r2">
<result type="redirect">/r2.jsp</result>
</action>
<action name="r3">
<result type="chain">r1</result>
</action>
<action name="r4">
<result type="redirectAction">r2</result>
</action>
</package>
</struts>
对于以下dispatcher:
URL: r/r1
显示:r1
<action name="r1"> <result type="dispatcher">/r1.jsp</result>
</action>
对于以下redirect:
URL: r/r2.jsp
显示:r2
<action name="r1">
<result type="redirect">/r2.jsp</result>
</action>
对于以下chain:
URL: r/r3
显示:r1
<action name="r1">
<result type="chain">r1</result>
</action>
注意: 如果forward到别的package的action的话, 需要用这个命令:\
<result type="chain"> <param name="actionname">dashboard</param> <param name="namespace">/secure</param> </result>
对于以下redirectAction:
URL: r/r2.jsp
显示:r2
<action name="r1">
<result type="redirectAction">r2</result>
</action>
- 全局结果集:
jsp:
<body> Result类型 <ol> <li><a href="user/user?type=1">返回success</a></li> <li><a href="user/user?type=2">返回error</a></li> <li><a href="user/user?type=3">返回global result</a></li> <li><a href="admin/admin">admin,继承user包</a></li> </ol> </body>
useraction:
@Override
public String execute() throws Exception {
if(type == 1) return "success";
else if (type == 2) return "error";
else return "mainpage";
}
如果很多action都有一个共同的结果页面, 比如上述的mainpage, 就可以单独提出来作为全局结果集:
如下struts.xml配置:
<struts>
<constant name="struts.devMode" value="true" />
<package name="user" namespace="/user" extends="struts-default">
<global-results>
<result name="mainpage">/main.jsp</result>
</global-results>
<action name="index">
<result>/index.jsp</result>
</action>
<action name="user" class="com.bjsxt.struts2.user.action.UserAction">
<result>/user_success.jsp</result>
<result name="error">/user_error.jsp</result>
</action>
</package>
<package name="admin" namespace="/admin" extends="user">
<action name="admin" class="com.bjsxt.struts2.user.action.AdminAction">
<result>/admin.jsp</result>
</action>
</package>
</struts>
如果admin的package要想使用全局结果局, 只需要继承user包即可:
extends="user"
- 动态结果集:dynamic result:
jsp页面:
<body> 动态结果 一定不要忘了为动态结果的保存值设置set get方法 <ol> <li><a href="user/user?type=1">返回success</a></li> <li><a href="user/user?type=2">返回error</a></li> </ol>
userAction:
package com.bjsxt.struts2.user.action;
import com.opensymphony.xwork2.ActionSupport;
public class UserAction extends ActionSupport {
private int type;
private String r;
public String getR() {
return r;
}
public void setR(String r) {
this.r = r;
}
public int getType() {
return type;
}
public void setType(int type) {
this.type = type;
}
@Override
public String execute() throws Exception {
if(type == 1) r="/user_success.jsp";
else if (type == 2) r="/user_error.jsp";
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>
<constant name="struts.devMode" value="true" />
<package name="user" namespace="/user" extends="struts-default">
<action name="user" class="com.bjsxt.struts2.user.action.UserAction">
<result>${r}</result>
</action>
</package>
</struts>
${r}用于从值栈 value stack里取值,每个action都有一个值栈
r在userAction里是动态确定的.所以叫做动态调用
此符号是xml配置文件里的Ognl表达式, 专门用于从action值栈里取出内容的.
- 带参数的结果集:
jsp:
<body> 向结果传参数 <ol> <li><a href="user/user?type=1">传参数</a></li> </ol> </body>
userAction:
package com.bjsxt.struts2.user.action;
import com.opensymphony.xwork2.ActionSupport;
public class UserAction extends ActionSupport {
private int type;
public int getType() {
return type;
}
public void setType(int type) {
this.type = type;
}
@Override
public String execute() throws Exception {
return "success";
}
}
struts.xml:
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE struts PUBLIC
"-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
"http://struts.apache.org/dtds/struts-2.0.dtd">
<struts>
<constant name="struts.devMode" value="true" />
<package name="user" namespace="/user" extends="struts-default">
<action name="user" class="com.bjsxt.struts2.user.action.UserAction">
<result type="redirect">/user_success.jsp?t=${type}</result>
</action>
</package>
</struts>
user_success.jsp:
因为是redirect客户端跳转, 所以不能共享一个值栈,即不能使用type, 所以要用t=${type}
也可以说一次request只有一个值栈,
<body> User Success! from valuestack: <s:property value="t"/><br/> //取不到 from actioncontext: <s:property value="#parameters.t"/> <s:debug></s:debug> </body>
<s:property value="t"/>格式属于从值栈取值, 因为是第二次request,当前没有action,所以没有值栈,也不能共用之前的值栈的值,
所以应该用<s:property value="#parameters.t"/>来取actionContext的值