Java 将自定义的对象作为HashMap的key

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需要继承Map的equals函数和hashCode函数

package com.category;import java.util.HashMap;public class GenCategoryLevelData {private static HashMap<Category, Integer> categoryLevel = new HashMap<Category, Integer>();/** * @param args */public static void main(String[] args) {// TODO Auto-generated method stub}/** * 分类 * @author ouyangyewei * */public static class Category {public long categoryId;public String categoryName;@Overridepublic boolean equals(Object obj) {Category category = (Category)obj;return (this.categoryId==category.categoryId&& this.categoryName.equals(category.categoryName));}@Overridepublic final int hashCode() {            int hashCode = 17;            hashCode = hashCode * 31 + 1;            hashCode = hashCode * 31 + 1;            return hashCode;        }public Category() {// empty}public Category(long categoryId, String categoryName) {this.categoryId = categoryId;this.categoryName = categoryName;}public long getCategoryId() {return categoryId;}public void setCategoryId(long categoryId) {this.categoryId = categoryId;}public String getCategoryName() {return categoryName;}public void setCategoryName(String categoryName) {this.categoryName = categoryName;}}}

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