1.首先当然是加入json-plugin jar包
2.编写action
public class UserAction extends ActionSupport implements ModelDriven<UserDTO>{
/**
*
*/
private static final long serialVersionUID = -1638994966822159495L;
private boolean userexsit=false;
private User user;
@Resource
private transient UserManager userManager;
private UserDTO userDTO=new UserDTO();
public String checkUser(){
if(this.userManager.exsit(userDTO.getUsername()))
this.userexsit=true;
return Action.SUCCESS;
}
public boolean getUserexsit() {
return userexsit;
}
public User getUser(){
return user;
}
public void setUserexsit(boolean userexsit) {
this.userexsit = userexsit;
}
@JSON(serialize=false)
public UserDTO getModel() {
return this.userDTO;
}
}
说明：只要有get方法，都会包含到json对象的属性，比如此useraction转为json如下：｛"userexsit":true;"model":{......}｝,
有时候我们只想指定的字段转为json，这时需要在xml里配置<param name="includeProperties">或还有一个忘 了。
3.xml配置
<package name="velidate" extends="json-default">
<action name="check/user" class="UserAction">
<result type="json">
<param name="includeProperties">
<!-- includeProperties用于过滤json包含的属性-->
userexsit<!--action里userexsit字段--> ，user\.name<!-- user字段只包含user对象的name属性-->
<!-- 注意的是，上面过滤条件都是正则表达式，如上面的user\.name里的.要用转义符，不然会是正则里.-->
</param>
</result>
</action>
</package>
4.javascript将返回string转为json对象
var exist=eval('('+value+')');
