关于异常positioned update are not supported总结
今天项目中遇到了positioned update are not supported这个异常
先看源代码吧
UserAction.java
public class UserAction extends ActionSupport{
?private String password;
?private User user;
?private String validateCode;
?private Boolean success;
?private String msg;
?
?public void setUser(User user) {
??this.user = user;
?}
?public User getUser() {
??return user;
?}
?public String getPassword() {
??return password;
?}
?public void setPassword(String password) {
??this.password = password;
?}
?public String getValidateCode() {
??return validateCode;
?}
?public void setValidateCode(String validateCode) {
??this.validateCode = validateCode;
?}
?public Boolean getSuccess() {
??return success;
?}
?public void setSuccess(Boolean success) {
??this.success = success;
?}
?public String getMsg() {
??return msg;
?}
?public void setMsg(String msg) {
??this.msg = msg;
?}
?@Resource private UserService userService;
?@SuppressWarnings("static-access")
?public String list(){
??String start =? ServletActionContext.getRequest().getParameter("start");
??String limit =? ServletActionContext.getRequest().getParameter("limit");
??Integer index = Integer.parseInt(start);
??Integer pageSize = Integer.parseInt(limit);
??String json = userService.convertAllUser(index,pageSize);
??//输出json对象
??HttpServletResponse response = ServletActionContext.getResponse();
??response.setContentType("Application/json;charset=GBK");
??response.setHeader("Cache-Control","no-cache");
??PrintWriter out = null;
??try {
???out = response.getWriter();
???out.print(json);
??} catch (IOException e) {
???// TODO Auto-generated catch block
???e.printStackTrace();
??}finally{
???if(out!=null){
????out.flush();
????out.close();
???}
??}
??return this.SUCCESS;
?}
?@SuppressWarnings("static-access")
?public String update(){
??HttpServletRequest request = ServletActionContext.getRequest();
??String jsonArray = request.getParameter("data");
??userService.saveAllUsers(jsonArray);
??return this.SUCCESS;
?}
?@SuppressWarnings("static-access")
?public String delete(){
??HttpServletRequest request = ServletActionContext.getRequest();
??String jsonArray = request.getParameter("data");
??userService.deleteAllUser(jsonArray);
??return this.SUCCESS;
?}
?@SuppressWarnings("static-access")
?public String checkUser(){
??String name = ServletActionContext.getRequest().getParameter("name");
??System.out.println(name);
??if(name!=null){
???List<User> users = userService.getUserByName(name);
???System.out.println("--------------------");
???System.out.println(users.size());
???System.out.println("--------------------");
???if(users.size()!=0){
????success = true;
????msg = "用户名已存在";
???}else{
????success = false;
????msg = "用户名可以注册";
???}
??}
??System.err.println(msg);
??System.out.println(success);
??return this.SUCCESS;
?}
?@SuppressWarnings("static-access")
?public String save(){
??String roleId = ServletActionContext.getRequest().getParameter("role_id");
??System.out.println(roleId);
??Integer role_id = Integer.parseInt(roleId);
??System.out.println(user);
??System.out.println(password);
??System.out.println(role_id);
??if(user!=null){
???userService.saveUser(user,role_id);
???success = true;
???msg = "保存成功";
??}
??return this.SUCCESS;
?}
?@SuppressWarnings("static-access")
?public String checkLogin(){
??String validate = (String) ActionContext.getContext().getSession().get("validateCode");
??if(validate.equals(validateCode.trim())){
???String userName = user.getUserName().trim();
???String psd = user.getPassword().trim();
???List<User> users = userService.getUserByName(userName);
???if(users.size()!=0){
????User user = users.get(0);
????if(user.getPassword().equals(psd)){
?????success = true;
?????msg = "登录成功";
?????Role role = user.getRole();
?????List<ACL> acls = role.getAcls();
?????List<UserAllInfo> userInfos = new ArrayList<UserAllInfo>();
?????ArrayList<Module> modules = new ArrayList<Module>();
?????HttpSession session = ServletActionContext.getRequest().getSession();
?????for(ACL acl :acls){
??????Module module = acl.getModule();
??????UserAllInfo userInfo = new UserAllInfo(module.getId(),acl.getPermission(),user.getUserName(),module.getText());
??????userInfos.add(userInfo);
??????modules.add(module);
?????}
?????session.setAttribute("user", user);
?????session.setAttribute("acl", acls);
?????session.setAttribute("role", role);
?????session.setAttribute("modules", modules);
?????session.setAttribute("userInfo", userInfos);
????}
???}else{
????success = false;
????msg = "用户名不存在";
???}
??}else{
???success = false;
???msg = "验证码错误";
??}
??return this.SUCCESS;
?}
}
UserService.java
@Service
public class UserService {
?@Resource private UserDAO? userDAO;
?@Resource private RoleDAO roleDAO;
?public List<User> getUsers(){
??return userDAO.getUsers();
?}
?@SuppressWarnings({ "unchecked", "deprecation" })
?public void saveAllUsers(String jsonUser){
??JSONArray jsonArray = JSONArray.fromObject(jsonUser);
??List<User> users = JSONArray.toList(jsonArray, User.class);
??for(User user :users){
????if(user!=null){
?????userDAO.update(user);
????}
??}
?}
?public String convertAllUser(Integer index,Integer pageSize){
??List<User> users = userDAO.getUsers();
??List<User> subUsers = null;
??int count = users.size();
??if((count%pageSize)<=0){
???subUsers = users.subList(0,count);
??}else if((count/pageSize)>index){
???subUsers = users.subList(index, pageSize);
??}else{
???subUsers = users.subList(((count/pageSize)*pageSize),count);
??}
??String json="";
??PropertyFilter filter = new PropertyFilter() {
???public boolean apply(Object source, String name, Object value) {
????// TODO Auto-generated method stub
????if(name.equals("role"))return true;
????return false;
???}
??};
??JsonConfig config = new JsonConfig();
??config.setJsonPropertyFilter(filter);
??if(users!=null){
???json+="{root:";
???json += JSONArray.fromObject(subUsers, config).toString();
???json+=",totalProperty:"+count+"}";
??}
??return json;
?}
?@SuppressWarnings({ "unchecked", "deprecation" })
?public void deleteAllUser(String jsonUser){
??JSONArray jsonArray = JSONArray.fromObject(jsonUser);
??List<User> users = JSONArray.toList(jsonArray, User.class);
??for(User user :users){
???int id = user.getId();
???if((user!=null)&&(id!=0)){
????userDAO.delete(id);
???}
??}
?}
?public void saveUser(User user,Integer role_id){
??Role role = roleDAO.getRoleById(role_id);
? user.setRole(role);
??userDAO.save(user);
?}
?public List<User> getUserByName(String userName){
??return userDAO.getUserByName(userName);
?}
}
加红的地方是我下面要讲的地方
先说下出现这个异常的原因吧 由于Role role = roleDAO.getRoleById(role_id);在获取role对象时对象里的个别属性是延迟加载的 当中有一些对象是延迟加载的，这些对象并不是原role类中的属性，而是由cglib这个字节码生成器动态生成的对象。Hibernate在这个子类中添加了hibernateLazyInitializer等等的附加属性。由于jsonplugin并不区分类和动态生成的类，所以也会试图序列化hibernateLazyInitializer属性，从而导致出现上述的异常。
思路如下：
1、判断这个对象是否由cglib生成的。代码如下：
boolean isCreateByCGLIB = clazz.getName().indexOf("$$EnhancerByCGLIB$$") > -1 ? true : false;
如果此对象确实是由cglib生成的，那么我们取此对象的基类，这一步很关键，因为通过取得此对象的基类，我们就忽略了所有由cglib生成的跟hibernate相关的属性。
2、通过反射，取得此对象的所有继续于基类的属性。
3、通过反射，取得此对象的所有get方法器（这一步不能省，不然出来的属性就少了）。
4、输出json。
可是我们需要user的getter 和setter方法 那不能去掉这两个方法怎么办呢? 那只有这样 在struts的配置文件中加一下配置
action name="user_*" method="{1}">
? ??<result name="success" type="json">
? ???<param name="excludeProperties">user</param>
? ??</result>
? ?</action>
在序列化action里属性时不序列化user这个属性 就可以了
