关于一个大map和多个小map的性能对比

话不多说，看结果  10万条数据，两种方法基本上差不多 


单位毫秒 

录入时间为：2226 

查找时间为：22 

----- 

录入时间为432 

查找时间为：13 


import java.util.*; 


public class MapTest2 { 


 public static void main(String ags[]) { 

 test2(); 

 System.out.println("-----"); 

 test1(); 

 } 


 public static void test1() { 

 Map m = new HashMap(100000); 

 long t0 = System.currentTimeMillis(); 

 for (int i = 0; i < 100000; i++) { 

 m.put("aa.bb.to.pub." + i + "12345asfsdfVO", "value"); 

 } 

 long t1 = System.currentTimeMillis(); 

 System.out.println(t1 - t0); 


 //随机取出1000个数字 

 for (int i = 0; i < 10000; i++) { 

 int j = new Random(10000).nextInt(); 

 m.get("aa.bb.to.pub." + j + "12345asfsdfVO"); 

 } 

 long t2 = System.currentTimeMillis(); 

 System.out.println(t2 - t1); 


 } 


 public static void test2() { 

 Map m = new HashMap(10); 

 m.put("aa.bb.ao", new HashMap(10000)); 

 m.put("aa.bb.bo", new HashMap(10000)); 

 m.put("aa.bb.co", new HashMap(10000)); 

 m.put("aa.bb.do", new HashMap(10000)); 

 m.put("aa.bb.eo", new HashMap(10000)); 

 m.put("aa.bb.fo", new HashMap(10000)); 

 m.put("aa.bb.go", new HashMap(10000)); 

 m.put("aa.bb.ho", new HashMap(10000)); 

 m.put("aa.bb.io", new HashMap(10000)); 

 m.put("aa.bb.jo", new HashMap(10000)); 

 long t0 = System.currentTimeMillis(); 

 for (int i = 0; i < 10; i++) { 


 for (int j = 0; j < 10000; j++){ 

 // 每个模块里有1000个 

 ((Map) m.get("aa.bb.ao")).put("aa.bb.to.pub." + j+ "12345asfsdfVO", "value"); 

 ((Map) m.get("aa.bb.bo")).put("aa.bb.to.pub." + j+ "12345asfsdfVO", "value"); 

 ((Map) m.get("aa.bb.co")).put("aa.bb.to.pub." + j+ "12345asfsdfVO", "value"); 

 ((Map) m.get("aa.bb.do")).put("aa.bb.to.pub." + j+ "12345asfsdfVO", "value"); 

 ((Map) m.get("aa.bb.eo")).put("aa.bb.to.pub." + j+ "12345asfsdfVO", "value"); 

 ((Map) m.get("aa.bb.fo")).put("aa.bb.to.pub." + j+ "12345asfsdfVO", "value"); 

 ((Map) m.get("aa.bb.go")).put("aa.bb.to.pub." + j+ "12345asfsdfVO", "value"); 

 ((Map) m.get("aa.bb.ho")).put("aa.bb.to.pub." + j+ "12345asfsdfVO", "value"); 

 ((Map) m.get("aa.bb.io")).put("aa.bb.to.pub." + j+ "12345asfsdfVO", "value"); 

 ((Map) m.get("aa.bb.jo")).put("aa.bb.to.pub." + j+ "12345asfsdfVO", "value"); 

 } 

 } 

 long t1 = System.currentTimeMillis(); 

 System.out.println("录入时间为：" + (t1 - t0));; 

 // System.out.println(m.get("8888key")); 

 for (int i = 1; i < 10000; i++) { 

 int j = new Random(10000).nextInt(); 

 ((Map) m.get("aa.bb.ao")).get("aa.bb.to.pub." + j+ "12345asfsdfVO"); 

 } 

 long t2 = System.currentTimeMillis(); 

 System.out.println("查找时间为：" + (t2 - t1)); 


 } 



}