豆如何正确使用？它们代表什么？

Question

Good day,

I am trying to use Spring framework in my java project and currently I am configuring the beans.xml file. I am new to Spring and I have difficulties on understanding how beans are used and what do they represent; I have read several documentations but still I need some clarification on this. Can anyone briefly explain what beans are and how are they used? Let's say, I have the following classes; what are beans in this case?

public class Repository {

private final Set<Integer> integers = new HashSet<Integer>();
private final Set<String> strings = new HashSet<String>();

public void addInt(int i) {
    integers.add(i);
}

public void addString(String s) {
    strings.add(s);
}

public Set<Integer> getInts() {
    return integers;
}

public Set<String> getStrings() {
    return strings;
}
}

and

public class Service {

private Repository repository;

public void createInt(int i) {
    repository.addInt(i);
}

public void createString(String s) {
    repository.addString(s);
}

public Set<Integer> getInts() {
    return repository.getInts();
}

public Set<String> getStrings() {
    return repository.getStrings();
}
}

Thank you

Answer 1

If you're not forced to use XML configuration, I'd recommend to use at least Spring 4.0.0 and make use of annotation based configuration with @Configuration @Bean .

In this case, a "Bean" can be any class you want to be spring managed. A Service, a DAO, whatever.