- P162-163
考察：HashSet集合
import java.util.HashSet; import java.util.Set; class Grain { private String name; public Grain(String name) { this.name = name; } public String getName() { return name; } @Override public boolean equals(Object o) { if (this == o) return true; if (o == null || getClass() != o.getClass()) return false; Grain grain = (Grain) o; return name.equals(grain.name); } @Override public int hashCode() { return name.hashCode(); } public void show() { } } public class HashSetExam { public static void main(String[] args) { Set<Grain> grainSet = new HashSet<>(); grainSet.add(new Grain("Wheat")); grainSet.add(new Grain("Rice")); grainSet.add(new Grain("Maize")); // 打印所有粮食 for (Grain grain : grainSet) { System.out.println(grain.getName()); } } }- P163
考察：TreeSet集合
import java.util.*; public class TestTreeSet { public static void main(String[] args) { Set ts = new TreeSet(); ts.add("长粒米"); ts.add("稻花香"); ts.add("珍珠米"); System.out.println(ts); } }- P164
考察：Comparable接口的compareTo方法
- P166
考察：Iterator迭代器的使用
import java.util.*; import com.dongsheng.farmproduce.*; class GrainView { public static void main(String[] args) { // 创建 HashSet 集合，用于存放车辆 Set grainSet = new HashSet(); // 创建 2 个大米对象、2 个小麦对象，并加入到 HashSet 集合中 Grain r1 = new Rice("长粒米","五常"); Grain r2 = new Rice("珍珠米","金龙鱼"); Grain w1 = new Wheat("烟农 999","安徽"); Grain w2 = new Wheat("丰德存麦 20","河南"); grainSet.add(r1); grainSet.add(r2); grainSet.add(w1); grainSet.add(w2); // 使用迭代器循环输出 Iterator it = grainSet.iterator(); while (it.hasNext()) { System.out.println("*** 显示集合中元素信息 ***"); Object obj = it.next(); if(obj instanceof Rice) { Rice rice = (Rice)obj; // 调用 Rice 类的特有方法 getBrand() System.out.println("大米品牌为:" + rice.getBrand()); }else{ Wheat wht = (Wheat) obj; // 调用 Wheat 类的特有方法 getMarket() System.out.println("小麦销售市场为:" + wht.getClass()); } // 调用 Grain 类方法 show() ((Grain)obj).show(); } } }- P168
考察：增强for循环
import java.util.*; public class ForEachLoop { public static void main(String[] args) { String[] names = {"西农 511","酒春 7 号","邯麦 19","克春 14 号"}; // 传统 for 循环遍历 for(int i = 0;i < names.length;i++){ System.out.println(names[i]); } // 增强 for 循环遍历 for(String elem:names){ System.out.println(elem); } Set wheatSet = new HashSet(); wheatSet.add("西农 511"); wheatSet.add("酒春 7 号"); wheatSet.add("邯麦 19"); wheatSet.add("克春 14 号"); // 迭代器遍历 Iterator it = wheatSet.iterator(); while (it.hasNext()){ System.out.println(it.next()); } // 增强 for 循环遍历 for(Object elem:wheatSet){ System.out.println((String)elem); } } }- P170
考察：ArrayList
- P174、P175两块相对大一些的代码
考察：泛型
