java基于反射得到对象属性值的方法

时间:2022-09-17 15:55:59

本文实例讲述了java基于反射得到对象属性值的方法。分享给大家供大家参考,具体如下:

通过反射机制得到对象中的属性和属性值 在对象中private没问题,在别的类中有时会报异常。下面的例子是在本对象中

?
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
/**
* Engine entity. @author MyEclipse Persistence Tools
*/
public class Engine implements java.io.Serializable {
 // Fields
 private Long engineId;
 private String engineName;
 private String engineType;
 // Constructors
 /** default constructor */
 public Engine() {
 }
 /** minimal constructor */
 public Engine(Long engineId) {
 this.engineId = engineId;
 }
 public Engine(String engineName, String engineType) {
 this.engineName = engineName;
 this.engineType = engineType;
 }
 /** full constructor */
 public Engine(Long engineId, String engineName, String engineType) {
 this.engineId = engineId;
 this.engineName = engineName;
 this.engineType = engineType;
 }
 // Property accessors
 public Long getEngineId() {
 return this.engineId;
 }
 public void setEngineId(Long engineId) {
 this.engineId = engineId;
 }
 public String getEngineName() {
 return this.engineName;
 }
 public void setEngineName(String engineName) {
 this.engineName = engineName;
 }
 public String getEngineType() {
 return this.engineType;
 }
 public void setEngineType(String engineType) {
 this.engineType = engineType;
 }
public static void main(String[] args) throws Exception {
 Engine m = new Engine("汽车","发动机");
 Class clazz = m.getClass();
 Field[] f = clazz.getDeclaredFields();
 String[] name = field2Name(f);
 Object[] value = field2Value(f, m);
 showNameAndValue(name, value);
 }
 public static void showNameAndValue(String[] name, Object[] value) {
 for (int i = 0; i < name.length; i++) {
  System.out.println("--" + i + "--");
  System.out.println("name:" + name[i]);
  System.out.println("Value:" + value[i]);
  System.out.println("--   --");
 }
 }
 public static String[] field2Name(Field[] f) {
 String[] name = new String[f.length];
 for (int i = 0; i < f.length; i++) {
  name[i] = f[i].getName();
 }
 return name;
 }
 public static Object[] field2Value(Field[] f, Object o) throws Exception {
 Object[] value = new Object[f.length];
 for (int i = 0; i < f.length; i++) {
  value[i] = f[i].get(o);
 }
 return value;
 }
}

如果想调用private的属性的属性值,则要调用他的get方法了具体做法是:

把field2Value方法改为如下方式,这样在别的类中也可以得到private的属性值了

?
1
2
3
4
5
6
7
8
9
10
11
12
public static Object[] field2Value(Field[] fields, Object o) throws Exception {
 Object[] values = new Object[fields.length];
 Class classType = o.getClass();
 for (int i = 0; i < fields.length; i++) {
  String fieldName = fields[i].getName();
  String firstLetter = fieldName.substring(0, 1).toUpperCase();
  String getMethodName = "get" + firstLetter + fieldName.substring(1);
  Method getMethod = classType.getMethod(getMethodName, new Class[] {});
  values[i] = getMethod.invoke(o, new Object[] {});
 }
 return values;
}

希望本文所述对大家java程序设计有所帮助。