GWT AppEngine 保存对象序列号.
想这个Google的app 都是可以先自己放一个免费的程序到服务器上面.
就是一个高兴的事情.
前几天研究了下GWT.关于做界面还是非常容易的.
java的代码想怎么写就怎么写.非常的高效率.
现在研究下如何将数据保存.
参考官方的文档.是通过JDO实现的.我也没有想太多.直接照着官方的文档写了个demo.
1.定义一个JDO对象.
package com.test.demo.jdo;
import javax.jdo.annotations.IdGeneratorStrategy;
import javax.jdo.annotations.IdentityType;
import javax.jdo.annotations.PersistenceCapable;
import javax.jdo.annotations.Persistent;
import javax.jdo.annotations.PrimaryKey;
@PersistenceCapable(identityType = IdentityType.APPLICATION)
public class LoginUser {
@PrimaryKey
@Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
private Long id;
@Persistent
private String userName;
@Persistent
private String passwd;
get set 方法和构造函数省略.
这里要说下.ID如果是要自增的话.id一定要用Long.而不能用String.
否则会报:ID自增错误.
然后用GWT写个对话框.
final DialogBox dialogBox = new DialogBox(false, true);
// false:是否自动隐藏.(单击DialogBox之外的部分.true:是否是模式对话框.
dialogBox.setTitle("登录对话框");
dialogBox.setText("登录对话框");
Grid grid = new Grid(3, 3);
grid.setWidget(0, 0, new HTML("登录名:"));
final TextBox userName = new TextBox();
userName.setValue("demo");
grid.setWidget(0, 1, userName);
grid.setWidget(1, 0, new HTML("密码:"));
final PasswordTextBox userPasswd = new PasswordTextBox();
userPasswd.setValue("demo");
grid.setWidget(1, 1, userPasswd);
final Button submit = new Button("新增");
submit.addClickHandler(new ClickHandler() {
public void onClick(ClickEvent event) {
// dialogBox.hide();
// GWT.
loginUserAction.saveLoginUser(userName.getValue(), userPasswd
.getValue(), new AsyncCallback<Void>() {
public void onSuccess(Void result) {
// TODO Auto-generated method stub
System.out.println("save !");
Window.alert("save!");
}
public void onFailure(Throwable caught) {
// TODO Auto-generated method stub
}
});
}
});
final Button cancle = new Button("长度");
cancle.addClickHandler(new ClickHandler() {
public void onClick(ClickEvent event) {
loginUserAction.findLoginUserSize(new AsyncCallback<Integer>() {
public void onSuccess(Integer result) {
// TODO Auto-generated method stub
Window.alert(result + "");
}
public void onFailure(Throwable caught) {
// TODO Auto-generated method stub
}
});
}
});
grid.setWidget(2, 0, submit);
grid.setWidget(2, 1, cancle);
dialogBox.add(grid);
dialogBox.center();
dialogBox.show();
// 将面板添加到dialog里面
private final LoginUserActionAsync loginUserAction = GWT .create(LoginUserAction.class);
在GWT里面调用jdo 保存数据和查询数据记录数.
http://toeoso.appspot.com/Login.html
public final class PMF {
private static final PersistenceManagerFactory pmfInstance =
JDOHelper.getPersistenceManagerFactory("transactions-optional");
private PMF() {}
public static PersistenceManagerFactory get() {
return pmfInstance;
}
}
看了下官方写了一个PMF类.我也拷贝了下.
public void deleteLoginUserById(String id) {
}
public void saveLoginUser(String userName, String userPasswd) {
PersistenceManager pm = PMF.get().getPersistenceManager();
try {
LoginUser loginUser = new LoginUser(userName, userPasswd);
//loginUser.setId(Math.abs(new Random().nextInt())+"");
pm.makePersistent(new LoginUser(userName, userPasswd));
}catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
} finally {
pm.close();
}
}
public int findLoginUserSize() {
PersistenceManager pm = PMF.get().getPersistenceManager();
try {
javax.jdo.Query query = pm.newQuery(LoginUser.class);
List<LoginUser> results = (List<LoginUser>) query.execute("Smith");
return results.size();
}catch (Exception e) {
e.printStackTrace();
return 0;
} finally {
pm.close();
}
}
用了下PMF.每次都要申请一个.然后在关闭下.不知道这么写对不对.
拷贝了下日志:
启动的时候创建了数据库表.
2009-9-19 11:22:00 com.google.apphosting.utils.jetty.JettyLogger info 信息: jetty-6.1.x 2009-9-19 11:22:00 com.google.apphosting.utils.jetty.JettyLogger info 信息: Started [email protected]:8080 The server is running at http://localhost:8080/ 2009-9-19 11:23:09 org.datanucleus.plugin.NonManagedPluginRegistry resolveConstraints INFO: Bundle "org.datanucleus.jpa" has an optional dependency to "org.datanucleus.enhancer" but it cannot be resolved 2009-9-19 11:23:09 org.datanucleus.plugin.NonManagedPluginRegistry resolveConstraints INFO: Bundle "org.datanucleus" has an optional dependency to "org.eclipse.equinox.registry" but it cannot be resolved 2009-9-19 11:23:09 org.datanucleus.plugin.NonManagedPluginRegistry resolveConstraints INFO: Bundle "org.datanucleus" has an optional dependency to "org.eclipse.core.runtime" but it cannot be resolved 2009-9-19 11:23:09 org.datanucleus.PersistenceConfiguration setProperty INFO: Property datanucleus.rdbms.sql.allowAllSQLStatements unknown - will be ignored 2009-9-19 11:23:09 org.datanucleus.PersistenceConfiguration setProperty INFO: Property datanucleus.rdbms.stringDefaultLength unknown - will be ignored 2009-9-19 11:23:09 org.datanucleus.PersistenceConfiguration setProperty INFO: Property datanucleus.appengine.autoCreateDatastoreTxns unknown - will be ignored 2009-9-19 11:23:09 org.datanucleus.ObjectManagerFactoryImpl logConfiguration INFO: ================= Persistence Configuration =============== 2009-9-19 11:23:09 org.datanucleus.ObjectManagerFactoryImpl logConfiguration INFO: DataNucleus Persistence Factory - Vendor: "DataNucleus" Version: "1.1.4" 2009-9-19 11:23:09 org.datanucleus.ObjectManagerFactoryImpl logConfiguration INFO: DataNucleus Persistence Factory initialised for datastore URL="appengine" driver="" userName="" 2009-9-19 11:23:09 org.datanucleus.ObjectManagerFactoryImpl logConfiguration INFO: =========================================================== 2009-9-19 11:23:09 org.datanucleus.PersistenceConfiguration setProperty INFO: Property datanucleus.query.cached unknown - will be ignored 2009-9-19 11:23:10 org.datanucleus.jdo.metadata.JDOMetaDataManager <init> INFO: Registering listener for metadata initialisation 2009-9-19 11:23:10 org.datanucleus.jdo.metadata.JDOAnnotationReader processClassAnnotations INFO: Class "com.test.demo.jdo.LoginUser" has been specified with JDO annotations so using those. 2009-9-19 11:23:10 org.datanucleus.store.appengine.MetaDataValidator validate INFO: Performing appengine-specific metadata validation for com.test.demo.jdo.LoginUser 2009-9-19 11:23:10 org.datanucleus.store.appengine.MetaDataValidator validate INFO: Finished performing appengine-specific metadata validation for com.test.demo.jdo.LoginUser 2009-9-19 11:23:10 org.datanucleus.store.StoreDataManager registerStoreData INFO: Managing Persistence of Class : com.test.demo.jdo.LoginUser [Table : <class name="LoginUser" identity-type="application" objectid-class="javax.jdo.identity.LongIdentity" persistence-modifier="persistence-capable" > <inheritance strategy="new-table"> </inheritance> <field name="id" persistence-modifier="persistent" primary-key="true" null-value="none" default-fetch-group="true" embedded="false" value-strategy="identity" unique="false"> </field> <field name="passwd" persistence-modifier="persistent" null-value="none" default-fetch-group="true" embedded="true" unique="false"> </field> <field name="userName" persistence-modifier="persistent" null-value="none" default-fetch-group="true" embedded="true" unique="false"> </field> </class> , InheritanceStrategy : new-table] 2009-9-19 11:23:10 org.datanucleus.store.StoreDataManager registerStoreData INFO: Managing Persistence of Class : com.test.demo.jdo.LoginUser [Table : <class name="LoginUser" identity-type="application" objectid-class="javax.jdo.identity.LongIdentity" persistence-modifier="persistence-capable" > <inheritance strategy="new-table"> </inheritance> <field name="id" persistence-modifier="persistent" primary-key="true" null-value="none" default-fetch-group="true" embedded="false" value-strategy="identity" unique="false"> </field> <field name="passwd" persistence-modifier="persistent" null-value="none" default-fetch-group="true" embedded="true" unique="false"> </field> <field name="userName" persistence-modifier="persistent" null-value="none" default-fetch-group="true" embedded="true" unique="false"> </field> </class> , InheritanceStrategy : new-table] 2009-9-19 11:23:11 com.google.appengine.api.datastore.dev.LocalDatastoreService load INFO: Time to load datastore: 141 ms 2009-9-19 11:23:11 org.datanucleus.jdo.metadata.JDOMetaDataManager$MetaDataRegisterClassListener registerClass INFO: Listener found initialisation for persistable class com.test.demo.jdo.LoginUser 2009-9-19 11:23:49 org.datanucleus.ObjectManagerImpl close INFO: Outstanding nontx update being committed to datastore save ! 2009-9-19 11:24:11 com.google.appengine.api.datastore.dev.LocalDatastoreService$PersistDatastore persist INFO: Time to persist datastore: 0 ms 2009-9-19 11:52:28 org.datanucleus.ObjectManagerImpl close INFO: Outstanding nontx update being committed to datastore save ! 2009-9-19 11:52:31 com.google.appengine.api.datastore.dev.LocalDatastoreService$PersistDatastore persist INFO: Time to persist datastore: 62 ms
我在运行的时候遇到了
点击按钮的时候怎么也不响应.报后台类错误.
2009-9-19 10:56:15 com.google.apphosting.utils.jetty.JettyLogger warn
警告: EXCEPTION
java.lang.ClassNotFoundException: com.demo.test.server.LoginUserActionImpl
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at com.google.appengine.tools.development.IsolatedAppClassLoader.loadClass(IsolatedAppClassLoader.java:142)
at java.lang.ClassLoader.loadClass(Unknown Source)
at org.mortbay.util.Loader.loadClass(Loader.java:91)
at org.mortbay.util.Loader.loadClass(Loader.java:71)
at org.mortbay.jetty.servlet.Holder.doStart(Holder.java:73)
at org.mortbay.jetty.servlet.ServletHolder.doStart(ServletHolder.java:233)
at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:40)
at org.mortbay.jetty.servlet.ServletHandler.initialize(ServletHandler.java:612)
at org.mortbay.jetty.servlet.Context.startContext(Context.java:139)
at org.mortbay.jetty.webapp.WebAppContext.startContext(WebAppContext.java:1218)
at org.mortbay.jetty.handler.ContextHandler.doStart(ContextHandler.java:500)
at org.mortbay.jetty.webapp.WebAppContext.doStart(WebAppContext.java:448)
at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:40)
at org.mortbay.jetty.handler.HandlerWrapper.doStart(HandlerWrapper.java:117)
at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:40)
at org.mortbay.jetty.handler.HandlerWrapper.doStart(HandlerWrapper.java:117)
at org.mortbay.jetty.Server.doStart(Server.java:217)
at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:40)
at com.google.appengine.tools.development.JettyContainerService.startContainer(JettyContainerService.java:152)
at com.google.appengine.tools.development.AbstractContainerService.startup(AbstractContainerService.java:116)
at com.google.appengine.tools.development.DevAppServerImpl.start(DevAppServerImpl.java:218)
at com.google.appengine.tools.development.gwt.AppEngineLauncher.start(AppEngineLauncher.java:86)
at com.google.gwt.dev.HostedMode.doStartUpServer(HostedMode.java:365)
at com.google.gwt.dev.HostedModeBase.startUp(HostedModeBase.java:590)
at com.google.gwt.dev.HostedModeBase.run(HostedModeBase.java:397)
at com.google.gwt.dev.HostedMode.main(HostedMode.java:232)
其实就是配置没有写对.类下面的这个和web.xml里面的要一致.
@RemoteServiceRelativePath("LoginUserAction")
public interface LoginUserAction extends RemoteService {
void saveLoginUser(String userName,String userPasswd);
void deleteLoginUserById(String id);
int findLoginUserSize();
}
<servlet>
<servlet-name>LoginUserAction </servlet-name>
<servlet-class>com.test.demo.server.LoginUserActionImpl</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>LoginUserAction </servlet-name>
<url-pattern>/com.test.demo.Login/LoginUserAction </url-pattern>
</servlet-mapping>
叫什么是无所谓了..而且在代码里面也不用.
只不过是GWT自己去找而已.
想着也挺方便的.
附件是代码.新增是将数据保存.长度是获得有几条数据.