struts2 Action获取表单传值

1.通过属性驱动式   
JSP:   
    <form action="sys/login.action" method="post">   
        <input type="text" name="username">   
        <input type="submit" value="submit">   
    </form>   
       
Action:直接通过get、set方法获取。   

public class sysAction extends ActionSupport{
private String username;

public String login() throws Exception {
System.out.println(username);
return SUCCESS;
}

public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username= username;
}
}

       
2.模型驱动方式，必须要实现ModelDriven<T>接口。对于要传入多个model第二种方式不方便   
JSP:   
    <form action="sys/login.action" method="post">   
        <input type="text" name="username">   
        <input type="submit" value="submit">   
    </form>   
       
Action:必须实现getModel() 方法   

public class sysAction extends ActionSupport implements ModelDriven<User>{
private User user;

public String login() throws Exception {
System.out.println(getModel().getUsername());
return SUCCESS;
}

public User getModel() {
if (null == user) {
return user = new User();
}
return user;
}
}     

3.第三种方式可以完全不实现ModelDriven<T>，也可使用多个model对象的属性。   
JSP:   
    <form action="sys/login.action" method="post">   
        <input type="text" name="user.username">   
        <input type="text" name="teacher.level">   
        <input type="submit" value="submit">   
    </form>   
       
Action: 必须提供set方法   

public class sysAction extends ActionSupport{
private User user;
private Teacher teacher;

public String login() throws Exception {
System.out.println(user.getUsername());
System.out.println(teacher.getLevel());
return SUCCESS;
}

public void setUser(User user) {
this.user = user;
}
public void setTeacher(Teacher teacher) {
this.teacher = teacher;
}
}