Java 在GWT的异步方法中传递异常的正确方法是什么？

我不确定在GWT的异步方法中传递异常的正确方法是什么。我有一个数据服务，它连接到数据库，查询信息，然后将信息返回给客户端。但我根本不明白在发生检查异常时该怎么做，以及如何处理它

现在我有这样的东西

public int addAssembler(int assemblerID, String name, boolean active) {
        Connection con = connect();
        PreparedStatement ps = null;
        ResultSet rs = null;
        try {
            String query = "INSERT INTO assemblers (name, hidden) VALUES ('" + name + "'," + active + ")";
            ps = con.prepareStatement(query);
            System.out.println("addAssembler " + ps.toString());
            ps.executeUpdate(query);
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            close(rs, ps, con);
        }
        return 1;
    }

它被称为这里

public void onClick(ClickEvent event) {
                Ioma.dataservice.addAssembler(0, name.getText(), !isActive.getValue(), new AsyncCallback<Integer>() {
                    @Override
                    public void onFailure(Throwable caught) {
                        Window.alert("Failed to add assembler! Please check error log" + caught.toString());
                    }

                @Override
                public void onSuccess(Integer result) {
                    Window.alert("Assembler " + name.getText() + " added");
                }
            });

但它给了我一个SQLException的源代码not found错误。我甚至不确定这样做是否正确？有更好的办法吗

请阅读文档

您不能抛出

SQLException

，因为客户端不知道这是什么。您可以做的是定义自己的异常类型（在客户端或共享包中）：

然后在服务方法中声明它：

public interface MyService extends RemoteService {
    int addAssembler(int assemblerID, String name, boolean active) throws DatabaseException;
}

然后您可以将其扔到服务器端：

public int addAssembler(int assemblerID, String name, boolean active) throws DatabaseException {
    Connection con = connect();
    PreparedStatement ps = null;
    ResultSet rs = null;
    try {
        String query = "INSERT INTO assemblers (name, hidden) VALUES ('" + name + "'," + active + ")";
        ps = con.prepareStatement(query);
        System.out.println("addAssembler " + ps.toString());
        ps.executeUpdate(query);
    } catch (SQLException e) {
        throw new DatabaseException(e); // <----- THIS IS IMPORTANT
    } finally {
        close(rs, ps, con);
    }
    return 1;
}

---

顺便说一句：对于所有的

异常，你不必这样做，只有那些不例外的。并且确保将其登录到服务器上。并且认真考虑向客户端发送SQL异常的完整堆栈跟踪和消息-如果发生SQL注入或连接字符串问题，您真的想发送“嘿，这是您打破我的方式！”向浏览器发送消息？
public interface MyService extends RemoteService {
    int addAssembler(int assemblerID, String name, boolean active) throws DatabaseException;
}

public int addAssembler(int assemblerID, String name, boolean active) throws DatabaseException {
    Connection con = connect();
    PreparedStatement ps = null;
    ResultSet rs = null;
    try {
        String query = "INSERT INTO assemblers (name, hidden) VALUES ('" + name + "'," + active + ")";
        ps = con.prepareStatement(query);
        System.out.println("addAssembler " + ps.toString());
        ps.executeUpdate(query);
    } catch (SQLException e) {
        throw new DatabaseException(e); // <----- THIS IS IMPORTANT
    } finally {
        close(rs, ps, con);
    }
    return 1;
}

@Override
public void onFailure(Throwable caught)
{
    if(caught instanceof DatabaseException)
        Window.alert(caught.getLocalizedMessage());
}