依赖注入的延续，延迟注入实践。我有主课：
package test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.stereotype.Component;
import java.util.List;
import java.util.Scanner;
@Component
public class Main {
@Autowired
private StringValidator stringValidator;
@Autowired
private StringService stringService;
@Autowired
private ValidationService validationService;
public void main() {
scanKeyboardCreateLists();
stringValidator.validate();
final List<String> validatedList = stringValidator.getValidatedList();
for (String currentValid : validatedList) {
System.out.println(currentValid);
}
}
private void scanKeyboardCreateLists() {
//Let's presume the user interacts with the GUI, dynamically changing the object graph...
//Needless to say, this is past container initialization...
Scanner scanner = new Scanner(System.in);
int choice = scanner.nextInt();
//Delayed creation, dynamic
if (choice == 0) {
stringService.createList();
validationService.createList();
} else {
stringService.createSecondList();
validationService.createSecondList();
}
}
public static void main(String[] args) {
ApplicationContext container = new ClassPathXmlApplicationContext("/META-INF/spring/applicationContext.xml");
container.getBean(Main.class).main();
}
}
并且对象图是动态创建的，取决于用户交互。我解决了应用程序耦合，让我可以非常简单地测试它。此外，由于列表由容器维护，因此此应用程序（以及其他所有应用程序）的动态特性是无关紧要的，因为可以在应用程序需要它们的任何时候请求它们，维护它们的元素。
其余代码在这里：
package test;
import java.util.List;
public interface Stringable {
List<String> getStringList();
}
package test;
import org.springframework.stereotype.Component;
import java.util.ArrayList;
@Component
public class StringList extends ArrayList<String> {
}
package test;
import org.springframework.stereotype.Component;
import javax.inject.Inject;
import java.util.ArrayList;
import java.util.List;
@Component
public class StringService implements Stringable {
private List<String> stringList;
@Inject
public StringService(final ArrayList<String> stringList) {
this.stringList = stringList;
}
//Simplified
public void createList() {
stringList.add("FILE1.txt");
stringList.add("FILE1.dat");
stringList.add("FILE1.pdf");
stringList.add("FILE1.rdf");
}
public void createSecondList() {
stringList.add("FILE2.txt");
stringList.add("FILE2.dat");
stringList.add("FILE3.pdf");
stringList.add("FILE3.rdf");
}
@Override
public List<String> getStringList() {
return stringList;
}
}
package test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import java.util.ArrayList;
import java.util.List;
@Component
public class StringValidator {
private List<String> stringList;
private List<String> validationList;
private final List<String> validatedList = new ArrayList<String>();
@Autowired
public StringValidator(final ArrayList<String> stringList,
final ArrayList<String> validationList) {
this.stringList = stringList;
this.validationList = validationList;
}
public void validate() {
for (String currentString : stringList) {
for (String currentValidation : validationList) {
if (currentString.equalsIgnoreCase(currentValidation)) {
validatedList.add(currentString);
}
}
}
}
public List<String> getValidatedList() {
return validatedList;
}
}
package test;
import java.util.List;
public interface Validateable {
List<String> getValidationList();
}
package test;
import org.springframework.stereotype.Component;
import java.util.ArrayList;
@Component
public class ValidationList extends ArrayList<String> {
}
package test;
import org.springframework.stereotype.Component;
import javax.inject.Inject;
import java.util.ArrayList;
import java.util.List;
@Component
public class ValidationService implements Validateable {
private List<String> validationList;
@Inject
public ValidationService(final ArrayList<String> validationList) {
this.validationList = validationList;
}
//Simplified...
public void createList() {
validationList.add("FILE1.txt");
validationList.add("FILE2.txt");
validationList.add("FILE3.txt");
validationList.add("FILE4.txt");
}
public void createSecondList() {
validationList.add("FILE5.txt");
validationList.add("FILE6.txt");
validationList.add("FILE7.txt");
validationList.add("FILE8.txt");
}
@Override
public List<String> getValidationList() {
return validationList;
}
}
有谁知道我将如何解决方法调用 createList() 或 createSecondList() - 不使用几乎强制设计的构造函数。我在想一个工厂，但是一个更大的项目中每个班级的工厂似乎不是一个好主意。
就像是：
<bean ... factory-method="..." depends-on="..." lazy-init="..."/>
并在工厂方法中实例化该类并调用方法 createList()。或者像这样从某个方法调用它——这又看起来很糟糕，迫使该方法有责任实例化对象图。
我想在运行时解决的运行时依赖关系的图片如下：
是否有其他方法可以根据用户交互使用容器来实现动态延迟初始化？
谢谢你。