Action接收參數的四種方法
- 在Action中定義屬性和get、set方法，Struts2將會自動把接受的參數賦值到對應的屬性：
public class UserAction extends ActionSupport { private String name; private int age; public String execute() {<span style="white-space:pre"> </span>//localhost:8080/Struts/user?name=aaa&age=20 return SUCCESS; } public String getName() { return name; } public void setName(String name) { this.name = name; } public int getAge() { return age; } public void setAge(int age) { this.age = age; } } - 在Action類中定義model對象並添加get、set方法，在model對象中定義屬性添加get、set方法，Struts2會將屬性傳入model中：
public class UserAction extends ActionSupport { private User user; public String execute() {<span style="white-space:pre"> </span>//localhost:8080/Struts/user?user.name=a&user.age=19 return SUCCESS; } public User getUser() { return user; } public void setUser(User user) { this.user = user; } } class User { private String name; private int age; public String getName() { return name; } public void setName(String name) { this.name = name; } public int getAge() { return age; } public void setAge(int age) { this.age = age; } } - 使用DTO進行中間過渡，用於參數中帶有不需要存入model的屬性時：
public class UserAction extends ActionSupport { private UserDTO user; public String execute() { //localhost:8080/Struts/user?user.username=a&user.password=b&user.confirmingPassword=b return SUCCESS; } public User getUser() { return user; } public void setUser(UserDTO user) { this.user = user; } } class UserDTO { private String username; private String password; private String confirmingPassword; public String getUsername() { return username; } public void setUsername(String username) { this.username = username; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } public String getConfirmingPassword() { return confirmingPassword; } public void setConfirmingPassword(String confirmingPassword) { this.confirmingPassword = confirmingPassword; } } - 實現ModelDriven接口，自行創建成員對象實例，實現getModel方法：
public class UserAction extends ActionSupport implements ModelDriven<User>{ private User user = new User(); public String add() { System.out.println("name=" + user.getName()); System.out.println("age=" + user.getAge()); return SUCCESS; } @Override public User getModel() { return user; } } class User { private String name; private int age; public String getName() { return name; } public void setName(String name) { this.name = name; } public int getAge() { return age; } public void setAge(int age) { this.age = age; } }
獲取Request、Session和Application的四種方法：
- 使用ActionContext獲取：
public class TestAction extends ActionSupport { private Map request; private Map session; private Map application; public TestAction() { request = (Map)ActionContext.getContext().get("request"); session = ActionContext.getContext().getSession(); application = ActionContext.getContext().getApplication(); } public String execute() { request.put("username", "aaa"); session.put("password", "bbb"); application.put("name", "ccc"); return SUCCESS; } } - 實現RequestAware、SessionAware、ApplicationAware接口，通過IOC注入獲取：
public class TestAction extends ActionSupport implements RequestAware,SessionAware, ApplicationAware { private Map<String, Object> request; private Map<String, Object> session; private Map<String, Object> application; public String execute() { request.put("username", "aaa"); session.put("password", "bbb"); application.put("name", "ccc"); return SUCCESS; } @Override public void setRequest(Map<String, Object> request) { this.request = request; } @Override public void setSession(Map<String, Object> session) { this.session = session; } @Override public void setApplication(Map<String, Object> application) { this.application = application; } } - 通過ServletActionContext獲取：
public class TestAction extends ActionSupport { private HttpServletRequest request; private HttpSession session; private ServletContext application; public TestAction() { request = ServletActionContext.getRequest(); session = request.getSession(); application = session.getServletContext(); } public String execute() { request.setAttribute("username", "aaa"); session.setAttribute("password", "bbb"); application.setAttribute("name", "ccc"); return SUCCESS; } } - 實現HttpRequestAware接口，通過IOC注入獲取：
public class TestAction extends ActionSupport implements ServletRequestAware { private HttpServletRequest request; private HttpSession session; private ServletContext application; public String execute() { request.setAttribute("username", "aaa"); session.setAttribute("password", "bbb"); application.setAttribute("name", "ccc"); return SUCCESS; } @Override public void setServletRequest(HttpServletRequest request) { this.request = request; this.session = request.getSession(); this.application = session.getServletContext(); } }
Result
Result標籤有兩個屬性type和name，其中type有4種常用選項，分別爲：
- dispatcher（默認選項）：轉發到一個頁面
- redirect：重定向到一個頁面
- chain：轉發到一個Action
- redirectAction ：重定向到一個Action
有些頁面可以爲所有Action服務，例如主頁、錯誤頁面等，可以使用<global-results>標籤將這些頁面的Result設置成全局Result：
<global-results>
<result name="error">/error.jsp</result>
<result name="main">/index.jsp</result>
</global-results>同時Result也支持動態結果集，用法爲"${r}"，r代表ValueStack中的一個屬性名。例如Action爲：
public class UserAction extends ActionSupport {
private int type;
private String url;
public String getUrl() {
return url;
}
public void setUrl(String url) {
this.url = url;
}
public int getType() {
return type;
}
public void setType(int type) {
this.type = type;
}
@Override
public String execute() throws Exception {
if(type == 1) url="/success.jsp";
else if (type == 2) url="/error.jsp";
return "success";
}
}<pre name="code" class="java"><action name="user" class="struts.action.UserAction">
<span style="white-space:pre"> </span><result>${url}</result>
</action>或者用於重定向傳遞參數：
<action name="user" class="struts.action.UserAction">
<result type="redirect">/user.jsp/type=${type}</result>
</action>