测试Java反射效率

测试分为3个方面：1. 实例化效率；2. 方法调用效率；3. 成员变量GET调用效率；4. 成员变量SET调用

测试环境：

Windows 7

Sun Java 1.6

 

先写好备测试用的类

import java.util.Date;


public class DemoClass{
	public String firstName;
	private String endName;
	private Date birthDay;
	private String email;
	private String phone;
	private DemoClass parent;
	
	public String getFirstName() {
    	return firstName;
    }
	public void setFirstName(String firstName) {
    	this.firstName = firstName;
    }
	public String getEndName() {
    	return endName;
    }
	public void setEndName(String endName) {
    	this.endName = endName;
    }
	public Date getBirthDay() {
    	return birthDay;
    }
	public void setBirthDay(Date birthDay) {
    	this.birthDay = birthDay;
    }
	public String getEmail() {
    	return email;
    }
	public void setEmail(String email) {
    	this.email = email;
    }
	public String getPhone() {
    	return phone;
    }
	public void setPhone(String phone) {
    	this.phone = phone;
    }
	public DemoClass getParent() {
    	return parent;
    }
	public void setParent(DemoClass parent) {
    	this.parent = parent;
    }
}

 

 

1. 实例化效率

1) 正常调用

public class TestReflectNew {

	public static void main(String[] args) throws Exception{
	    
	    int i = 0;
	    long start = System.currentTimeMillis();
	    while(i<1000000){
	    	i++;
//	    	DemoClass.class.newInstance();
	    	new DemoClass();
	    }
	    
	    long end = System.currentTimeMillis();
	    System.err.println((end - start) + " MillSeconds");
    }
}

三次输出：

18 MillSeconds

19 MillSeconds

20 MillSeconds

均值：19

 

2) 反射调用

public class TestReflectNew {

	public static void main(String[] args) throws Exception{
	    
	    int i = 0;
	    long start = System.currentTimeMillis();
	    while(i<1000000){
	    	i++;
	    	DemoClass.class.newInstance();
//	    	new DemoClass();
	    }
	    
	    long end = System.currentTimeMillis();
	    System.err.println((end - start) + " MillSeconds");
    }
}

 三次输出：

191 MillSeconds

193 MillSeconds
192 MillSeconds

均值：192

 

2. 方法调用测试

1) 正常调用

public class TestReflectMethod {

	public static void main(String[] args) throws Exception{
	    
	    int i = 0;
	    DemoClass dc = new DemoClass();
	    long start = System.currentTimeMillis();
	    while(i<1000000){
	    	i++;
//	    	DemoClass.class.getMethod("getBirthDay").invoke(dc);
	    	dc.getBirthDay();
	    }
	    
	    long end = System.currentTimeMillis();
	    System.err.println((end - start) + " MillSeconds");
    }
}

 三次输出：

2 MillSeconds

2 MillSeconds

2 MillSeconds

均值：2

2) 反射调用

public class TestReflectMethod {

	public static void main(String[] args) throws Exception{
	    
	    int i = 0;
	    DemoClass dc = new DemoClass();
	    long start = System.currentTimeMillis();
	    while(i<1000000){
	    	i++;
	    	DemoClass.class.getMethod("getBirthDay").invoke(dc);
//	    	dc.getBirthDay();
	    }
	    
	    long end = System.currentTimeMillis();
	    System.err.println((end - start) + " MillSeconds");
    }
}

 三次输出：

1223 MillSeconds

1201 MillSeconds

1207 MillSeconds

均值1210

 

3. 测试成员变量GET

1) 正常调用

public class TestReflectFieldGet {

	public static void main(String[] args) throws Exception{
	    
	    int i = 0;
	    DemoClass dc = new DemoClass();
	    String s;
	    long start = System.currentTimeMillis();
	    while(i<1000000){
	    	i++;
//	    	s = (String) DemoClass.class.getField("firstName").get(dc);
	    	s = dc.firstName;
	    }
	    
	    long end = System.currentTimeMillis();
	    System.err.println((end - start) + " MillSeconds");
    }
}

 三次输出：

2 MillSeconds

1 MillSeconds

3 MillSeconds

均值：2

 

2) 反射调用

public class TestReflectFieldGet {

	public static void main(String[] args) throws Exception{
	    
	    int i = 0;
	    DemoClass dc = new DemoClass();
	    String s;
	    long start = System.currentTimeMillis();
	    while(i<1000000){
	    	i++;
	    	s = (String) DemoClass.class.getField("firstName").get(dc);
//	    	s = dc.firstName;
	    }
	    
	    long end = System.currentTimeMillis();
	    System.err.println((end - start) + " MillSeconds");
    }
}

 三次输出：

992 MillSeconds

1000 MillSeconds

1005 MillSeconds

均值：999

 

4. 测试成员变量SET

1) 正常调用

public class TestReflectFieldSet {

	public static void main(String[] args) throws Exception {
	    
	    int i = 0;
	    DemoClass dc = new DemoClass();
	    String s = null;
	    long start = System.currentTimeMillis();
	    while(i<1000000){
	    	i++;
	    	dc.firstName = s;
//	    	DemoClass.class.getField("firstName").set(dc, s);
	    }
	    
	    long end = System.currentTimeMillis();
	    System.err.println((end - start) + " MillSeconds");
    }
}

 三次输出：

1 MillSeconds

2 MillSeconds

2 MillSeconds

均值：1.7

2) 反射调用

public class TestReflectFieldSet {

	public static void main(String[] args) throws Exception {
	    
	    int i = 0;
	    DemoClass dc = new DemoClass();
	    String s = null;
	    long start = System.currentTimeMillis();
	    while(i<1000000){
	    	i++;
//	    	dc.firstName = s;
	    	DemoClass.class.getField("firstName").set(dc, s);
	    }
	    
	    long end = System.currentTimeMillis();
	    System.err.println((end - start) + " MillSeconds");
    }
} 

三次输出：

998 MillSeconds

1021 MillSeconds

1007 MillSeconds

均值：1009

 

来个统计

	反射平均时间	非反射平均时间	比值
实例化	192	19	10
方法调用	1210	2	605
成员Get	999	2	500
成员Set	1009	1.7	593

 

 

以上测试的方式如果有不合理的地方请eye友们指点，看看测试的方法是否得当，是否全面

 

本人新博客：tuoxie.me