Question

我正在为Web开发人员使用Eclipse Java EE IDE。

版本：Helios Service Release 2 建造ID：20110218-0911

目前我正在编写一个书店项目，但是在编译ShoppingCart.java时，它会显示

“ - java.util.function.Consumer类型无法解析。它是从必需的.class间接引用的文件

- The type java.util.function.Consumer cannot be resolved. It is indirectly referenced from required .class 
 files

- The type java.util.function.Predicate cannot be resolved. It is indirectly referenced from required .class files

- The type java.util.function.UnaryOperator cannot be resolved. It is indirectly referenced from 
 required .class files

- The type java.util.Comparator cannot be resolved. It is indirectly referenced from required .class files"

一开始。这是Book.java

package bookstore;

import java.io.Serializable;

public class Book implements Serializable {
private static final long serialVersionUID = 1L;
private String isbn;
private String author;
private String title;
private double price;
private int edition;
private String publisher;
private String copyright;
public Book(String isbn, String author, String title, double price, int edition, String publisher, String copyright) {
    this.isbn = isbn;
    this.author = author;
    this.title = title;
    this.price = price;
    this.edition = edition;
    this.publisher = publisher;
    this.copyright = copyright;
}
public String getIsbn() {
    return isbn;
}
public String getAuthor() {
    return author;
}
public int getEdition() {
    return edition;
}
public String getPublisher() {
    return publisher;
}
public String getCopyright() {
    return copyright;
}
public String getTitle() {
    return title;
}
public void setTitle(String title) {
    this.title = title;
}
public double getPrice() {
    return price;
}
public void setPrice(double price) {
    this.price = price;
}
}

和ShoppingCart.java

package bookstore;
import java.util.*;
import java.util.ArrayList;


public class ShoppingCart extends ArrayList<Book> {
private static final long serialVersionUID = 1L;
public ShoppingCart() {
}

public void addBook(Book book) {
    this.add(book);
}

public Book getBook(int i) {
    return this.get(i);
}

public double getTotalPrice() {
    double price = 0.0;
    for (Book book : this) {
        price += book.getPrice();
    }
    return price;
}
}

我没有包含Consumer，Predicate，UnaryOperator和Comparator的功能。我发现问题可能是由于“extends ArrayList”

Answer 1

这是一个令人烦恼的Eclipse Bug，似乎偶尔会咬人。见http://dev-answers.blogspot.de/2009/06/eclipse-build-errors-javalangobject.html

获取可能的解决方案，否则请尝试以下操作;

关闭项目并重新打开它。清理项目（它将重建构建路径，从而使用JDK库重新配置）

OR

删除并重新导入项目，如有必要，请再次执行上述步骤。

Eclipse

1 个答案: