java容器

BasicContainer.java

import java.util.*;

public class BasicContainer {
public static void main(String[] args) {
Collection c = new HashSet();
c.add("hello");
c.add(new Name("f1","l1"));
c.add(new Integer(100));
c.remove("hello");
c.remove(new Integer(100));
System.out.println
(c.remove(new Name("f1","l1")));
System.out.println(c);
}

}

class Name implements Comparable {
private String firstName,lastName;
public Name(String firstName, String lastName) {
this.firstName = firstName; this.lastName = lastName;
}
public String getFirstName() {  return firstName;   }
public String getLastName() {   return lastName;   }
public String toString() {  return firstName + " " + lastName;  }

public boolean equals(Object obj) {
if (obj instanceof Name) {
Name name = (Name) obj;
return (firstName.equals(name.firstName))
&& (lastName.equals(name.lastName));
}
return super.equals(obj);
}
public int hashCode() {
return firstName.hashCode();
}

public int compareTo(Object o) {
Name n = (Name)o;
int lastCmp =
lastName.compareTo(n.lastName);
return
(lastCmp!=0 ? lastCmp :
firstName.compareTo(n.firstName));
}

}

TestMap.java

import java.util.*;
public class TestMap {
public static void main(String args[]) {
Map m1 = new HashMap();
Map m2 = new TreeMap();
//m1.put("one",new Integer(1));
m1.put("one", 1);
//m1.put("two",new Integer(2));
m1.put("two", 2);
//m1.put("three",new Integer(3));
m1.put("three", 3);
//m2.put("A",new Integer(1));
m2.put("A", 1);
//m2.put("B",new Integer(2));
m2.put("B", 2);
System.out.println(m1.size());
System.out.println(m1.containsKey("one"));
System.out.println
//(m2.containsValue(new Integer(1)));
(m2.containsValue(1));
if(m1.containsKey("two")) {
//int i = ((Integer)m1.get("two")).intValue();
int i = (Integer)m1.get("two");
System.out.println(i);
}
Map m3 = new HashMap(m1);
m3.putAll(m2);
System.out.println(m3);
}
}TestMap2.java

import java.util.*;
public class TestMap2 {
public static void main(String args[]) {
Map<String, Integer> m1 = new HashMap<String , Integer>();
m1.put("one", 1);
m1.put("two", 2);
m1.put("three", 3);

System.out.println(m1.size());
System.out.println(m1.containsKey("one"));

if(m1.containsKey("two")) {
//int i = ((Integer)m1.get("two")).intValue();
int i = m1.get("two");
System.out.println(i);
}

}
}
TestArgsWords.javaimport java.util.*;
public class TestArgsWords {
//private static final Integer ONE = new Integer(1);
private static final int ONE = 1;
public static void main(String args[]) {
Map m = new HashMap();
for (int i = 0; i < args.length; i++) {
//Integer freq = (Integer) m.get(args[i]);

int freq = (Integer) m.get(args[i]) == null ? 0 : (Integer) m.get(args[i]);
//m.put(args[i],(freq == null? ONE : new Integer(freq.intValue() + 1)));
m.put(args[i], freq==0 ? ONE : freq + 1);
}
System.out.println
(m.size() + " distinct words detected:");
System.out.println(m);
}
}
TestArgsWords2.java

import java.util.*;
public class TestArgsWords2 {
private static final int ONE = 1;
public static void main(String args[]) {
Map<String, Integer> m = new HashMap<String, Integer>();
for (int i = 0; i < args.length; i++) {

if(!m.containsKey(args[i])) {
m.put(args[i], ONE);
}
else {
int freq = m.get(args[i]);
m.put(args[i], freq + 1);
}

}
System.out.println
(m.size() + " distinct words detected:");
System.out.println(m);
}
}

EnhancedFor.javaimport java.util.*;

public class EnhancedFor {
public static void main(String[] args) {
int[] arr = {1, 2, 3, 4, 5};
for(int i : arr) {
System.out.println(i);
}

Collection c = new ArrayList();
c.add(new String("aaa"));
c.add(new String("bbb"));
c.add(new String("ccc"));
for(Object o : c) {
System.out.println(o);
}
}
}

BasicGeneric.java

import java.util.*;

public class BasicGeneric {
public static void main(String[] args) {
List<String> c = new ArrayList<String>();
c.add("aaa");
c.add("bbb");
c.add("ccc");
for(int i=0; i<c.size(); i++) {
String s = c.get(i);
System.out.println(s);
}

Collection<String> c2 = new HashSet<String>();
c2.add("aaa"); c2.add("bbb"); c2.add("ccc");
for(Iterator<String> it = c2.iterator(); it.hasNext(); ) {
String s = it.next();
System.out.println(s);
}
}
}

class MyName implements Comparable<MyName> {
int age;

public int compareTo(MyName mn) {
if(this.age > mn.age) return 1;
else if(this.age < mn.age) return -1;
else return 0;
}
}