他们都是一个容器 很简单的 你就对着API文档 创建一个 然后往里面加东西 然后输出一下就可以了 import java.util.*;public class TestArrayList{ public static void main(String args[]){ ArrayList<String> al = new ArrayList<String>();
al.add("a"); al.add("c"); al.add("b");
for(String s : al) System.out.print(s +" "); } }
package ttt;import java.util.ArrayList; import java.util.Arrays;public class Sort { public Sort() { super(); // TODO 自动生成构造函数存根 } public void sort(ArrayList al) { Object[] obj = new Object[al.size()]; for (int i = 0; i < obj.length; i++) { obj[i] = al.get(i); System.out.println(obj[i]); } Arrays.sort(obj); System.out.println("adjflkajfkljsajfjdkf"); for (int i = 0; i < obj.length; i++) { System.out.println(obj[i]); } } public static void main(String[] args) { ArrayList al = new ArrayList(); al.add(new dtp("stl", 35)); al.add(new dtp("ssl", 75)); al.add(new dtp("lss", 20)); al.add(new dtp("sls", 30)); al.add(new dtp("sll", 35)); al.add(new dtp("lsl", 98)); new Sort().sort(al); } }
package ttt;import java.util.Date;public class MailSendDateBean implements Comparable<Date> { private String msgID = ""; private Date sentDate = null; public MailSendDateBean(String msgID, Date sentDate) { super(); this.msgID = msgID; this.sentDate = sentDate; } public String getMsgID() { return msgID; } public void setMsgID(String msgID) { this.msgID = msgID; } public Date getSentDate() { return sentDate; } public void setSentDate(Date sentDate) { this.sentDate = sentDate; } public int compareTo(Date date) { return 0; } public String toString() { return this.msgID + " ";//+ this.sentDate; } }
package ttt;public class dtp implements Comparable { public dtp(String name, int num) { super(); // TODO 自动生成构造函数存根 this.name = name; this.num = num; } public dtp() { super(); // TODO 自动生成构造函数存根 } private String name = null; private int num = 0; public String getName() { return name; } public void setName(String name) { this.name = name; } public int getNum() { return num; } public void setNum(int num) { this.num = num; } public int compareTo(Object o) { // TODO 自动生成方法存根 int a = this.num; int b = ((dtp) o).num; return ((a == b) ? 0 : ((a < b) ? 1 : -1)); } public String toString() { return this.name + " " + this.num; } }
Vector:用于线程同步的,因为它速度慢,但是安全
HashMap:是用于非线程同步的,因为它速度快,效率高,同时允许设置值为null
Hashtable:用于线程同步的,因为它速度慢,但是安全
例子很多的
public static void main(String args[]){
ArrayList<String> al = new ArrayList<String>();
al.add("a");
al.add("c");
al.add("b");
for(String s : al)
System.out.print(s +" ");
}
}
import java.util.Arrays;public class Sort { public Sort() {
super();
// TODO 自动生成构造函数存根
} public void sort(ArrayList al) {
Object[] obj = new Object[al.size()];
for (int i = 0; i < obj.length; i++) {
obj[i] = al.get(i);
System.out.println(obj[i]);
} Arrays.sort(obj);
System.out.println("adjflkajfkljsajfjdkf");
for (int i = 0; i < obj.length; i++) {
System.out.println(obj[i]); }
} public static void main(String[] args) {
ArrayList al = new ArrayList();
al.add(new dtp("stl", 35));
al.add(new dtp("ssl", 75));
al.add(new dtp("lss", 20));
al.add(new dtp("sls", 30));
al.add(new dtp("sll", 35));
al.add(new dtp("lsl", 98));
new Sort().sort(al); }
}
super();
this.msgID = msgID;
this.sentDate = sentDate;
} public String getMsgID() {
return msgID;
} public void setMsgID(String msgID) {
this.msgID = msgID;
} public Date getSentDate() {
return sentDate;
} public void setSentDate(Date sentDate) {
this.sentDate = sentDate;
} public int compareTo(Date date) {
return 0;
} public String toString() {
return this.msgID + " ";//+ this.sentDate;
}
}
super();
// TODO 自动生成构造函数存根
this.name = name;
this.num = num;
} public dtp() {
super();
// TODO 自动生成构造函数存根
} private String name = null;
private int num = 0; public String getName() {
return name;
} public void setName(String name) {
this.name = name;
} public int getNum() {
return num;
} public void setNum(int num) {
this.num = num;
} public int compareTo(Object o) {
// TODO 自动生成方法存根
int a = this.num;
int b = ((dtp) o).num;
return ((a == b) ? 0 : ((a < b) ? 1 : -1));
} public String toString() {
return this.name + " " + this.num;
}
}