Question

我有2个班级，一流的学院和第二个讲师。在大学课堂上我有＆gt;＆gt; public Lecturer [] allLecturer;

我希望大学系接收讲师部门，但是当我试图打印大学系时，我有些奇怪。

班级讲师：

public class Lecturer {
public String name;
public int numOfTimesPenFalls;
public String favoriteIceCream;
public int autoNumber;

//constructor
public Lecturer(String Name, int NumOfTimesPenFalls,
        String FavoriteIceCream, int AutoNumber) {
    this.name = Name;
    this.numOfTimesPenFalls = NumOfTimesPenFalls;
    this.favoriteIceCream = FavoriteIceCream;
    this.autoNumber = AutoNumber;
}

@Override
public String toString(){
    return "name: " +name+ " num Of Times Pen Falls: "+ numOfTimesPenFalls +
    " favorite Ice Cream: " + favoriteIceCream + " auto Number: " + autoNumber;
}
}

班级学院：

public class College {
public String name;
public int numOfLecturer;
public Lecturer[] allLecturer;
public int maxLecturer;

//constructor
public College(String Name, int NumOfLecturer, Lecturer[] AllLecturer, int MaxLecturer) {
    this.name = Name;
    this.numOfLecturer = NumOfLecturer;
    this.allLecturer = AllLecturer;
    this.maxLecturer = MaxLecturer;
}

public College(String Name){
    this.name = Name;
}

@Override
public String toString(){
    return "Name College: " +name+ " num Of Lecturer: " + numOfLecturer + 
    " all Lecturer: " + allLecturer + " max Lecturer " + maxLecturer ;
}
}

主：

public class main {
public static void main(String[] args) {

    Lecturer[] L1 = new Lecturer[] { new Lecturer("David", 3, "Banana",
            1001) };

    College myCollege = new College("College1", 20, L1, 10);

    System.out.println(myCollege.toString());

}
}

结果输出：

Name College: College1 num Of Lecturer: 20 all Lecturer: [LLecturer;@139a55 max Lecturer 10

为什么它给我打印（[LLecturer; @ 139a55]而不是部门的详细信息？

如果我在main for循环中写道：

for (int i = 0; i < L1.length; i++) {
        System.out.println(L1[i]);
    }

结果输出：

 name: David num Of Times Pen Falls: 3 favorite Ice Cream: Banana auto Number: 1001

如何解决此问题，以便在我打印课程(System.out.println(myCollege.toString()) );时我还打印了讲师部门的信息？

谢谢你。

Answer 1

嘿，当你用字符串连接一个数组时，它将使用他的toString函数。默认的toString函数将打印您在代码中看到的内容。数组中单个对象的toString将打印出您想要的内容。

Answer 2

Java数组不会覆盖Object的toString（）方法。只需将您编写的循环添加到College

的toString（）方法中

示例解决方案：

@Override
public String toString(){
    return "Name College: " +name+ " num Of Lecturer: " + numOfLecturer + 
    " all Lecturer: " + java.util.Arrays.toString(allLecturer) + " max Lecturer " + maxLecturer ;
}

如果您可以使用第三方库，请查看Apache的StringUtils类，它有一个方便的join()方法，可以从连续的对象数组中生成一个String

Answer 3

将toString()中的College.java方法更改为

@Override
public String toString(){
    return "Name College: " +name+ " num Of Lecturer: " + numOfLecturer + 
    " all Lecturer: " + Arrays.toString(allLecturer) + " max Lecturer " + maxLecturer ;
}

并在您的主要方法中尝试打印您的College参考

College myCollege = new College("College1", 20, L1, 10);
System.out.println(myCollege);

现在你的输出是：

Name College: College1 num Of Lecturer: 20 all Lecturer: [name: David num Of Times Pen Falls: 3 favorite Ice Cream: Banana auto Number: 1001] max Lecturer 10

Java类 - 数组println

3 个答案: