java反射如何通俗易懂理解-金沙1005

 1 public class customer {
 2     
 3     private long id;
 4     private string name;
 5     private int age;
 6       
 7     public customer() {}
 8     
 9     public customer(string name,int age) {
10         this.name = name;
11         this.age = age;
12     }
13       
14     public long getid() {
15         return id;
16     }
17     public void setid(long id) {
18         this.id=id;
19     }
20     public string getname() {
21         return name;
22     }
23     public void setname(string name) {
24         this.name=name;
25     }
26     public int getage() {
27         return age;
28     }
29     public void setage(int age) {
30         this.age=age;
31     }
32 
33 }

希望我今天分享的这篇文章可以帮到您。

 1 import java.lang.reflect.field;
 2 import java.lang.reflect.method;
 3 
 4 public class reflecttester {
 5     
 6     public object copy(object object) throws exception{
 7         //获得对象的类型
 8         class classtype=object.getclass();
 9         system.out.println("class:" classtype.getname());
10 
11         //通过默认构造方法创建一个新的对象
12         object objectcopy=classtype.getconstructor(new class[]{}).newinstance(new object[]{});
13 
14         //获得对象的所有属性
15         field fields[]=classtype.getdeclaredfields();
16 
17         for(int i=0; i){
18               field field=fields[i];
19 
20               string fieldname=field.getname();
21               string firstletter=fieldname.substring(0,1).touppercase();
22               //获得和属性对应的getxxx()方法的名字
23               string getmethodname="get" firstletter fieldname.substring(1);
24               //获得和属性对应的setxxx()方法的名字
25               string setmethodname="set" firstletter fieldname.substring(1);
26 
27               //获得和属性对应的getxxx()方法
28               method getmethod=classtype.getmethod(getmethodname,new class[]{});
29               //获得和属性对应的setxxx()方法
30               method setmethod=classtype.getmethod(setmethodname,new class[]{field.gettype()});
31 
32               //调用原对象的getxxx()方法
33               object value=getmethod.invoke(object,new object[]{});
34               system.out.println(fieldname ":" value);
35               //调用拷贝对象的setxxx()方法
36              setmethod.invoke(objectcopy,new object[]{value});
37         }
38         return objectcopy;
39      }
40 
41 }

class classtype=object.getclass();

object objectcopy=classtype.getconstructor(new class[]{}).newinstance(new object[]{});

field fields[]=classtype.getdeclaredfields();

method addmethod=classtype.getmethod("add",new class[]{int.class,int.class});

1 public static void main(string[] args) throws exception {
2 　　customer customer = new customer();
3 　　customer.setid(10l);
4 　　customer.setname("adam");
5 　　customer.setage(3);
6         
7 　　new reflecttester().copy(customer);
8 }   

 1 import java.io.file;  2 import java.lang.reflect.field;  3 import java.lang.reflect.method;  4 import java.net.url;  5 import java.net.urlclassloader;  6 import java.util.enumeration;  7 import java.util.jar.jarentry;  8 import java.util.jar.jarfile;  9 10 /** 11  * @classname: reflexdemo 12  * @description: 通过反射获取类、属性及方法 13  * @author adamjwh 14  * @date 2018年5月28日 15  * 16 */ 17 public class reflexdemo { 18 19 private static stringbuffer sbuffer; 20 21 public static void getjar(string jar) throws exception { 22 try { 23 file file = new file(jar); 24 url url = file.touri().to; 25 urlclassloader classloader = new urlclassloader(new url[] { url }, 26  thread.currentthread().getcontextclassloader()); 27 28 jarfile jarfile = new jarfile(jar); 29 enumeration enumeration = jarfile.entries(); 30  jarentry jarentry; 31 32 sbuffer = new stringbuffer(); //存数据 33 34 while (enumeration.hasmoreelements()) { 35 jarentry = enumeration.nextelement(); 36 37 if (jarentry.getname().indexof("meta-inf") < 0) { 38 string classfullname = jarentry.getname(); 39 if (classfullname.indexof(".class") < 0) { 40 classfullname = classfullname.substring(0, classfullname.length() - 1); 41 } else { 42 // 去除后缀.class，获得类名 43 string classname = classfullname.substring(0, classfullname.length() - 6).replace("/", "."); 44 class myclass = classloader.loadclass(classname); 45 sbuffer.append("类名\t："   classname); 46 system.out.println("类名\t："   classname); 47 48 // 获得属性名 49 class clazz = class.forname(classname); 50 field[] fields = clazz.getdeclaredfields(); 51 for (field field : fields) { 52 sbuffer.append("属性名\t："   field.getname()   "\n"); 53 system.out.println("属性名\t："   field.getname()); 54 sbuffer.append("-属性类型\t："   field.gettype()   "\n"); 55 system.out.println("-属性类型\t："   field.gettype()); 56  } 57 58 // 获得方法名 59 method[] methods = myclass.getmethods(); 60 for (method method : methods) { 61 if (method.tostring().indexof(classname) > 0) { 62 sbuffer.append("方法名\t："   method.tostring().substring(method.tostring().indexof(classname))   "\n"); 63 system.out.println("方法名\t："   method.tostring().substring(method.tostring().indexof(classname))); 64  } 65  } 66 sbuffer.append("--------------------------------------------------------------------------------"   "\n"); 67 system.out.println("--------------------------------------------------------------------------------"); 68  } 69  } 70  } 71 } catch (exception e) { 72  e.printstacktrace(); 73 } finally { 74 sbuffer.append("end"); 75 system.out.println("end"); 76 77 writefile.write(sbuffer); //写文件 78  } 79  } 80 81 }

 1 import java.io.bufferedwriter;  2 import java.io.file;  3 import java.io.filewriter;  4  5 /**  6  * @classname: writefile  7  * @description: 写文件操作  8  * @author adamjwh  9  * @date 2018年5月28日 10  * 11 */ 12 public class writefile { 13 14 private static string pathname = "src/com/adamjwh/jnp/ex14/out.txt"; 15 16 public static void write(stringbuffer sbuffer) throws exception { 17 file file = new file(pathname); 18 bufferedwriter bw = new bufferedwriter(new filewriter(file)); 19 20  bw.write(sbuffer.tostring()); 21  bw.close(); 22  } 23 24 }

 1 /**  2  * @classname: main  3  * @description:  4  * @author adamjwh  5  * @date 2018年5月28日  6  *  7 */  8 public class main {  9 10 private static string jar = "lib/dt.jar"; 11 12 public static void main(string[] args) throws exception { 13  reflexdemo.getjar(jar); 14  } 15 16 }