泛型基础(一)

onewayonelife

GenericFoo
package org.wp.activity;public class GenericFoo<T> {private T foo;public T getFoo() {return foo;}public void setFoo(T foo) {this.foo = foo;}public static void main(String args[]) {GenericFoo<Boolean> foo1 = new GenericFoo<Boolean>();GenericFoo<Integer> foo2 = new GenericFoo<Integer>();GenericFoo foo3 = new GenericFoo();foo1.setFoo(new Boolean(false));foo2.setFoo(new Integer(3));foo3.setFoo("hello");Boolean b = foo1.getFoo();Integer i = foo2.getFoo();String s = (String) foo3.getFoo();System.out.println(b);System.out.println(i);System.out.println(s);}} 
Generic
package org.wp.activity;public class Generic<T1, T2> {private T1 foo1;private T2 foo2;public T1 getFoo1() {return foo1;}public void setFoo1(T1 foo1) {this.foo1 = foo1;}public T2 getFoo2() {return foo2;}public void setFoo2(T2 foo2) {this.foo2 = foo2;}public static void main(String args[]) {Generic<Integer, Boolean> foo = new Generic<Integer, Boolean>();foo.setFoo1(new Integer(-20));foo.setFoo2(new Boolean(false));System.out.println(foo.getFoo1());System.out.println(foo.getFoo2());}} 
GenericArray
package org.wp.activity;public class GenericArray<T> {private T[] fooArray;public T[] getFooArray() {return fooArray;}public void setFooArray(T[] fooArray) {this.fooArray = fooArray;}public static void main(String args[]) {GenericArray<String> foo = new GenericArray<String>();String[] str1 = { "hello", "world", "welcome" };String[] str2 = null;foo.setFooArray(str1);str2 = foo.getFooArray();for (String s : str2) {System.out.println(s);}}} 
SimpleCollection
package org.wp.activity;public class SimpleCollection<T> {private T[] objArr = null;private int index = 0;public SimpleCollection() {objArr = (T[]) new Object[10];}public SimpleCollection(int capacity) {objArr = (T[]) new Object[capacity];}public void add(T t) {objArr[index++] = t;}public T get(int i) {return objArr;}public int getLength() {return this.index;}public static void main(String args[]) {SimpleCollection<Integer> c = new SimpleCollection<Integer>();for (int i = 0; i < 10; i++) {c.add(new Integer(i));}for (int i = 0; i < c.getLength(); i++) {Integer j = c.get(i);System.out.println(j);}}} 
WrapperFoo
package org.wp.activity;public class WrapperFoo<T> {private GenericFo<T> foo;public GenericFo<T> getFoo() {return foo;}public void setFoo(GenericFo<T> foo) {this.foo = foo;}public static void main(String args[]) {GenericFo<Integer> foo = new GenericFo<Integer>();foo.setFoo(new Integer(-10));WrapperFoo<Integer> wrapper = new WrapperFoo<Integer>();wrapper.setFoo(foo);GenericFo<Integer> gf = wrapper.getFoo();System.out.println(gf.getFoo());}}class GenericFo<T> {private T foo;public T getFoo() {return foo;}public void setFoo(T foo) {this.foo = foo;}} 
ArrayListTest
package org.wp.activity;import java.util.ArrayList;import java.util.Iterator;import java.util.List;public class ArrayListTest {public static void main(String args[]) {List<String> list = new ArrayList<String>();list.add("a");list.add("b");list.add("c");list.add("d");list.add("e");for (int i = 0; i < list.size(); i++) {String value = list.get(i);System.out.println(value);}for (Iterator<String> iter = list.iterator(); iter.hasNext();) {String value = iter.next();System.out.println(value);}}} 
SetTest
package org.wp.activity;import java.util.HashSet;import java.util.Iterator;import java.util.Set;public class SetTest {public static void main(String args[]) {Set<String> set = new HashSet<String>();set.add("aa");set.add("bb");set.add("cc");for (Iterator<String> iter = set.iterator(); iter.hasNext();) {String value = iter.next();System.out.println(value);}Set<People> setpeo = new HashSet<People>();setpeo.add(new People("zhangsan", 20, "beijing"));setpeo.add(new People("lisi", 30, "shanghai"));setpeo.add(new People("wangwu", 40, "tianjin"));for (Iterator<People> iter = setpeo.iterator(); iter.hasNext();) {People people = iter.next();String name = people.getName();int age = people.getAge();String address = people.getAddress();System.out.println("People [name=" + name + ", address=" + address + ", age=" + age + "]");}}}class People {private String name;private int age;private String address;public People(String name, int age, String address) {this.name = name;this.age = age;this.address = address;}@Overridepublic int hashCode() {final int prime = 31;int result = 1;result = prime * result + ((address == null) ? 0 : address.hashCode());result = prime * result + age;result = prime * result + ((name == null) ? 0 : name.hashCode());return result;}@Overridepublic boolean equals(Object obj) {if (this == obj)return true;if (obj == null)return false;if (getClass() != obj.getClass())return false;People other = (People) obj;if (address == null) {if (other.address != null)return false;} else if (!address.equals(other.address))return false;if (age != other.age)return false;if (name == null) {if (other.name != null)return false;} else if (!name.equals(other.name))return false;return true;}public String getName() {return name;}public void setName(String name) {this.name = name;}public int getAge() {return age;}public void setAge(int age) {this.age = age;}public String getAddress() {return address;}public void setAddress(String address) {this.address = address;}} 
MapTest
package org.wp.activity;import java.util.HashMap;import java.util.Iterator;import java.util.Map;import java.util.Set;public class MapTest {public static void main(String args[]) {Map<String, String> map = new HashMap<String, String>();map.put("a", "aa");map.put("b", "bb");map.put("c", "cc");map.put("d", "dd");map.put("e", "ee");Set<String> set = map.keySet();for (Iterator<String> iter = set.iterator(); iter.hasNext();) {String key = iter.next();String value = map.get(key);System.out.println(value);}System.out.println("=====================================");Set<Map.Entry<String, String>> entrySet = map.entrySet();for (Iterator<Map.Entry<String, String>> iter = entrySet.iterator(); iter.hasNext();) {Map.Entry<String, String> entry = iter.next();String key = entry.getKey();String value = entry.getValue();System.out.println("key:" + key + ",value:" + value);}}}