我一直在努力使Guice工作,但最终结果是:
类必须具有一个(也只有一个)构造函数
我的界面:
public interface AddrBookStore {
public Contact getContactByKey(String key);
public void addContact(Contact c);
}
实现:
public class RdbmsBasedAddrBookStore implements AddrBookStore {
private Connection connection;
public RdbmsBasedAddrBookStore(Connection connection) {
this.connection = connection;
}
@Override
public Contact getContactByKey(String key) throws AddrBookException
{}
@Override
public void addContact(Contact c) throws AddrBookException
{}
}
绑定模块:
public class ABguiceConfingModule extends AbstractModule {
@Override
protected void configure() {
bind(AddrBookStore.class).to(RdbmsBasedAddrBookStore.class);
}
}
AddrBook
我要注入的客户:
public class AddrBook {
private AddrBookStore store;
@Inject
public AddrBook(AddrBookStore store)
{
this.store = store;
}
... other methods;
}
而我的主要:
public class App
{
public static void main( String[] args ) throws Exception
{
Injector injector = Guice.createInjector(new ABguiceConfingModule() );
AddrBookStore store = injector.getInstance( AddrBookStore.class );
AddrBook book = new AddrBook(store);
AddrBookCLI cli = new AddrBookCLI(book);
cli.interact(new InputStreamReader(System.in), new OutputStreamWriter(System.out));
}}
毕竟,我得到了这个错误:
1) Could not find a suitable constructor in addrbook.store.RdbmsBasedAddrBookStore. Classes must have either one (and only one) constructor annotated with @Inject or a zero-argument constructor that is not private.
[ERROR] at addrbook.store.RdbmsBasedAddrBookStore.class(RdbmsBasedAddrBookStore.java:23)
[ERROR] at addrbook.ABguiceConfingModule.configure(ABguiceConfingModule.java:13)
我对Spring有经验,而对Guice没有经验。我在哪里错了?
AddrBookStore
。您需要具有的绑定Connection
,然后需要使用来注释构造函数@Inject
。您已经设置了AddrBookStore
该类,但显然它包装了Rdbms ...,但您尚未设置Rdbms
。
在Guice中有很多方法可以做到这一点,在这种情况下,我可能会使用来完成Provider<Connection>
,这样您就可以拥有一个完整的类来放置用于旋转与数据库的连接的代码,如下所示:
public class ConnectionProvider implements Provider<Connection> {
public Connection get() {
// put your code that connects to the database here
}
}
那么您的模块将是:
public class ABguiceConfingModule extends AbstractModule {
@Override
protected void configure() {
bind(AddrBookStore.class).to(RdbmsBasedAddrBookStore.class);
bind(Connection.class).toProvider(ConnectionProvider.class);
}
}
最后是您的AddrBookStore
:
public class RdbmsBasedAddrBookStore implements AddrBookStore {
private Connection connection;
@Inject
public RdbmsBasedAddrBookStore(Connection connection) {
this.connection = connection;
}
@Override
public Contact getContactByKey(String key) throws AddrBookException
{}
@Override
public void addContact(Contact c) throws AddrBookException
{}
}
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