javax.jdo.JDOUserException:持久类;“聊天用户”;数据库中没有表
我正在从h2数据库中检索数据。我的问题在q.setClass()中。 这里我试图设置表chatUsers.class,数据库有相同的类,但这表明没有表chatUsers。那么我能做些什么呢 如果我不写q.setClass()。然后它会给出数据,但问题是我无法得到那个类的列表 聊天用户类javax.jdo.JDOUserException:持久类;“聊天用户”;数据库中没有表,java,jdo,datanucleus,Java,Jdo,Datanucleus,我正在从h2数据库中检索数据。我的问题在q.setClass()中。 这里我试图设置表chatUsers.class,数据库有相同的类,但这表明没有表chatUsers。那么我能做些什么呢 如果我不写q.setClass()。然后它会给出数据,但问题是我无法得到那个类的列表 聊天用户类 import javax.jdo.JDOHelper; import javax.jdo.PersistenceManager; import javax.jdo.PersistenceManagerFactor
import javax.jdo.JDOHelper;
import javax.jdo.PersistenceManager;
import javax.jdo.PersistenceManagerFactory;
import javax.jdo.Query;
import javax.jdo.annotations.IdGeneratorStrategy;
import javax.jdo.annotations.PersistenceCapable;
import javax.jdo.annotations.Persistent;
import javax.jdo.annotations.PrimaryKey;
import java.util.List;
import java.util.Properties;
@PersistenceCapable(detachable="true")
public class ChatUsers {
@PrimaryKey
@Persistent(valueStrategy = IdGeneratorStrategy.INCREMENT)
int id;
String user;
String mobileNo;
String email;
String password;
public ChatUsers(String user, String password, String mobileNo, String email) {
this.user = user;
this.mobileNo = mobileNo;
this.email = email;
this.password = password;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getUser() {
return user;
}
public void setUser(String user) {
this.user = user;
}
public String getMobileNo() {
return mobileNo;
}
public void setMobileNo(String mobileNo) {
this.mobileNo = mobileNo;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
}
检索逻辑
public static List<ChatUsers> getAllUsersList() {
PersistenceManagerFactory pmf = JDOHelper.getPersistenceManagerFactory(setProperties());
PersistenceManager pm = pmf.getPersistenceManager();
List<ChatUsers> chatUsersList = null;
pm.currentTransaction().begin();
try {
Query q = pm.newQuery("javax.jdo.query.SQL","SELECT * FROM `CHATUSERS`");
q.setClass(ChatUsers.class);//This line has error
chatUsersList = (List<ChatUsers>) q.execute();
}catch (Exception ex)
{
System.out.println(ex);
}
return chatUsersList;
}
在执行()查询时,应该使用executeList()。[1]
另一种解决方案可能是使用setResultClass()而不是setClass()。[1]
第一种解决方案的一个例子是:
Query query = pm.newQuery("javax.jdo.query.SQL", "SELECT MY_ID, MY_NAME FROM MYTABLE");
query.setClass(MyClass.class);
List<MyClass> results = query.executeList();
Query Query=pm.newQuery(“javax.jdo.Query.SQL”,“从MYTABLE中选择MY_ID、MY_名称”);
query.setClass(MyClass.class);
列表结果=query.executeList();
[1] 搜索“设置候选类”
和“定义结果类型”
“在文档URL中:
Query query = pm.newQuery("javax.jdo.query.SQL", "SELECT MY_ID, MY_NAME FROM MYTABLE");
query.setClass(MyClass.class);
List<MyClass> results = query.executeList();