如何使用 Joiner 仅加入特定属性?

How can I use Joiner, to join only specific properties?

假设我有这个 class:

public class MyClass {
    private String propertyOne;
    private String propertyTwo;
    // getters setters...
}

现在,在我的测试方法中,我正在尝试类似的东西:

List<MyClass> myList = myListDao.findAll(); 
String aStringFullOfPropertyOnesOfAllMyObjects =  Joiner.on(", ").join(myList.iterator());

String,我想找回来的是这样的:

"propOneOfObjectOne, propOneOfObjectTwo, propOneOfObjectThree"

我该怎么做?

"old-school"解决方法:

您可以使用内置的标准 StringBuilder:

StringBuilder builder = new StringBuilder();
Iterator<MyClass> iter = myList.iterator();
for (MyClass object = iter.next(); iter.hasNext();) {
    builder.append(object.getPropertyOne());
    if (iter.hasNext()) {
         builder.append(", ");    
    }
}
String result = builder.toString();

使用连接器:

使用链接答案中的 Joiner

Joiner.on(", ").join(Iterables.transform(myList, new Function<MyClass, String>() {
    public String apply(MyClass object) { return object.getPropertyOne(); }
}));