Java基础知识

Author: uodut

.classpath

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+<?xml version="1.0" encoding="UTF-8"?>
+<classpath>
+	<classpathentry kind="src" path="src"/>
+	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-1.8"/>
+	<classpathentry kind="output" path="bin"/>
+</classpath>

.gitignore

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+/bin/

.project

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+<?xml version="1.0" encoding="UTF-8"?>
+<projectDescription>
+	<name>JavaBase1.7</name>
+	<comment></comment>
+	<projects>
+	</projects>
+	<buildSpec>
+		<buildCommand>
+			<name>org.eclipse.jdt.core.javabuilder</name>
+			<arguments>
+			</arguments>
+		</buildCommand>
+	</buildSpec>
+	<natures>
+		<nature>org.eclipse.jdt.core.javanature</nature>
+	</natures>
+</projectDescription>

.settings/org.eclipse.jdt.core.prefs

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+eclipse.preferences.version=1
+org.eclipse.jdt.core.compiler.codegen.inlineJsrBytecode=enabled
+org.eclipse.jdt.core.compiler.codegen.targetPlatform=1.8
+org.eclipse.jdt.core.compiler.codegen.unusedLocal=preserve
+org.eclipse.jdt.core.compiler.compliance=1.8
+org.eclipse.jdt.core.compiler.debug.lineNumber=generate
+org.eclipse.jdt.core.compiler.debug.localVariable=generate
+org.eclipse.jdt.core.compiler.debug.sourceFile=generate
+org.eclipse.jdt.core.compiler.problem.assertIdentifier=error
+org.eclipse.jdt.core.compiler.problem.enumIdentifier=error
+org.eclipse.jdt.core.compiler.source=1.8

CollectionNote

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+Collection
+	List:����,Ԫ�ؿ��ظ� 
+		ArrayList�����飬��ɾ�������ҿ죬��ͬ��������nullֵ����װ��һ����̬�ٷ���Ķ�������
+		LinkedList����������ɾ�죬����������ͬ��������nullֵ��
+		vector:ͬ�����̰߳�ȫ��Ч�ʵ�
+	Set:Ԫ��Ψһ,û���ظ�ֵ
+		HashSet:����null,��ͬ�����̲߳���ȫ
+		TreeSet:����null,��ͬ�����̲߳���ȫ��Ԫ������
+		EnumSet:��ֵ����Ϊö�����ͣ�������ʹ�� null Ԫ�أ�Ԫ�����򣨱�������˳��
+		LinkedHashSet:����null����ͬ�����̲߳���ȫ��
+	Deque:һ������ collection��֧�������˲�����Ƴ�Ԫ�أ���double ended queue:˫�˶��е���д��
+		ArrayDeque:����˫�˶��У���ֹnullԪ�أ���ͬ����
+	Queue:���У�������nullԪ��
+		PriorityQueue:
+�̰߳�ȫ��ͬ������Ч�ʱȽϵ�,�̲߳���ȫ����ͬ������Ч�ʱȽϸ�.
+Map
+	HashMap:key��value����Ϊnull���̲߳���ȫ������hash����Map�ӿ�ʵ��
+	Hashtable:key��value��������Ϊnull���̰߳�ȫ����ϣ��
+	TreeMap:key��value������Ϊnull���̲߳���ȫ�����ں������һ����ƽ��IJ�������
+	EnumMap:ö��ӳ�������м����������Ե���ö������,����nullֵ,�̲߳���ȫ��
+	LinkedHashMap:�ӿڵĹ�ϣ���������б�ʵ�֣�˫�������б�������ģ�����˳��һ��)��������HashMapһ��
+	WeakHashMap��
+	IdentityHashMap

Generic通配符

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+package BasicDao;
+
+public class Person_HashSet {
+	public Person_HashSet(){
+		
+	}
+	public Person_HashSet(int age,String name){
+		this.age = age;
+		this.name = name;
+	}
+	private String name;
+	private int age;
+	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;
+	}
+	@Override
+	public int hashCode() {
+		final int prime = 31;
+		int result = 1;
+		result = prime * result + age;
+		result = prime * result + ((name == null) ? 0 : name.hashCode());
+		return result;
+	}
+	@Override
+	public boolean equals(Object obj) {
+		if (this == obj)
+			return true;
+		if (obj == null)
+			return false;
+		if (getClass() != obj.getClass())
+			return false;
+		Person_HashSet other = (Person_HashSet) obj;
+		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;
+	}
+	
+}

src/BasicDao/Person_HashSet.java

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+package BasicDao;
+
+public class Person_TreeMap {
+	private int score;
+	private String name;
+	public int getScore() {
+		return score;
+	}
+	public void setScore(int score) {
+		this.score = score;
+	}
+	public String getName() {
+		return name;
+	}
+	public void setName(String name) {
+		this.name = name;
+	}
+	public Person_TreeMap(int score, String name) {
+		this.score = score;
+		this.name = name;
+	}
+}

src/BasicDao/Person_TreeMap.java

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+package BasicDao;
+
+public class Person_TreeSet implements Comparable<Object>{
+	private int age;
+	private String name;
+	public int getAge() {
+		return age;
+	}
+	public void setAge(int age) {
+		this.age = age;
+	}
+	public String getName() {
+		return name;
+	}
+	public void setName(String name) {
+		this.name = name;
+	}
+	public Person_TreeSet(int age, String name) {
+		this.age = age;
+		this.name = name;
+	}
+	@Override
+	public int compareTo(Object o) {
+		Person_TreeSet pt = (Person_TreeSet)o;
+		int ageCompareResult = this.age - pt.getAge();
+		int nameCompare = this.name.compareTo(pt.getName());
+		//比较规则：年龄相同按照姓名顺序排序，年龄不同按照年龄大小排序
+		int nameCompareResult = ageCompareResult == 0?nameCompare:ageCompareResult;
+		return nameCompareResult;
+	}
+	/*TreeSet<Student> ts = new TreeSet<Student>(new Comparator<Student>() {
+	    public int compare(Student s1, Student s2) {
+	     // 比较年龄
+	     int ageCompareResult = s1.getAge() - s2.getAge();
+	     // 比较姓名
+	     int nameCompare = s1.getName().compareTo(s2.getName());
+	     // 年龄相同比较姓名，年龄不同按照年龄排序
+	     int nameCompareResult = ageCompareResult == 0 ? nameCompare
+	      : ageCompareResult;
+	     return nameCompareResult;
+	   }
+	   });*/
+	
+}

src/BasicDao/Person_TreeSet.java

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+package BasicDao;
+
+public class Person_TreeSet2{
+	private int age;
+	private String name;
+	public int getAge() {
+		return age;
+	}
+	public void setAge(int age) {
+		this.age = age;
+	}
+	public String getName() {
+		return name;
+	}
+	public void setName(String name) {
+		this.name = name;
+	}
+	public Person_TreeSet2(int age, String name) {
+		this.age = age;
+		this.name = name;
+	}
+}