2 
  3 import java.lang.reflect.Field;
  4 import java.lang.reflect.InvocationTargetException;
  5 import java.lang.reflect.Method;
  6 import java.util.ArrayList;
  7 import java.util.Arrays;
  8 import java.util.List;
  9 
 10 public class MyCheck {
 11     public static void main(String[] args) throws
 
 IllegalAccessException,
 12             IllegalArgumentException, InvocationTargetException {
 13         MyCheck check = new MyCheck();
 14         Student student = new Student();
 15         student.setName("zzzz");
 16         student.setAddress("sss");
 17         student.setIdno("");
 18 //        student.setPhone("sss");
 

 19         check.test1(student);
 20 
 21     }
 22 
 23     public void test(Student student) throws IllegalAccessException,
 24             IllegalArgumentException, InvocationTargetException {
 25         CheckParamUtil<Student> checkParamUtil = new CheckParamUtil<Student>();
 26         checkParamUtil.checkParam(student);
 
 27         System.out.println("student:" + student);
 28     }
 29 
 30     public void test1(Student student) throws IllegalAccessException,
 31             IllegalArgumentException, InvocationTargetException {
 32         CheckParamUtil<Student> checkParamUtil = new CheckParamUtil<Student>();
 33         checkParamUtil.checkParam(student, "name", "address", "idno");
 34         System.out.println("student:" + student);
 35     }
 36 
 37 }
 38 
 39 class Student {
 40     private String name;
 41     private int age;
 42     private String address;
 43     private String idno;
 44     private String phone;
 45 
 46     public Student() {
 47     }
 48 
 49     public Student(String name, int age, String address, String idno,
 50             String phone) {
 51         super();
 52         this.name = name;
 53         this.age = age;
 54         this.address = address;
 55         this.idno = idno;
 56         this.phone = phone;
 57     }
 58 
 59     public String getName() {
 60         return name;
 61     }
 62 
 63     public void setName(String name) {
 64         this.name = name;
 65     }
 66 
 67     public int getAge() {
 68         return age;
 69     }
 70 
 71     public void setAge(int age) {
 72         this.age = age;
 73     }
 74 
 75     public String getAddress() {
 76         return address;
 77     }
 78 
 79     public void setAddress(String address) {
 80         this.address = address;
 81     }
 82 
 83     public String getIdno() {
 84         return idno;
 85     }
 86 
 87     public void setIdno(String idno) {
 88         this.idno = idno;
 89     }
 90 
 91     public String getPhone() {
 92         return phone;
 93     }
 94 
 95     public void setPhone(String phone) {
 96         this.phone = phone;
 97     }
 98 
 99     @Override
100     public String toString() {
101         return "Student [name=" + name + ", age=" + age + ", address="
102                 + address + ", idno=" + idno + ", phone=" + phone + "]";
103     }
104 
105     public void a() {
106         System.out.println("haha");
107     }
108 }
109 
110 class CheckParamUtil<T> {
111     /**
112      * 
113      * @Title:checkParam
114      * @Description:(該方法用來校驗對象及其屬性是否為空)
115      * @param t
116      * @param args
117      * @author
118      * @throws InvocationTargetException
119      * @throws IllegalArgumentException
120      * @throws IllegalAccessException
121      * @修改時間：2017年6月9日 下午2:18:54
122      * @修改內容：創建
123      */
124     public void checkParam(T t, String... args) throws IllegalAccessException,
125             IllegalArgumentException, InvocationTargetException {
126         // 如果傳入的對象為空，則直接跑出異常
127         if (t == null) {
128             throw new IllegalArgumentException("This object cann‘t be empty!");
129         }
130         Class<? extends Object> clazz = t.getClass();
131         // 定義屬性列表
132         List<String> argsList = new ArrayList<String>();
133         // 如果傳入的屬性名不為空，則將傳入的屬性名放入屬性列表
134         if (args != null && args.length > 0) {
135             argsList = Arrays.asList(args);
136         } else {// 如果傳入的屬性名為空，則將所有屬性名放入屬性列表
137             Field[] fields = clazz.getDeclaredFields();
138             for (Field field : fields) {
139                 argsList.add(field.getName());
140             }
141         }
142         // 獲取該類自定義的方法數組
143         Method[] methods = clazz.getDeclaredMethods();
144         for (Method method : methods) {
145             // 方法名
146             String methodName = method.getName();
147             // 獲取方法對應的屬性名
148             String fieldName = "";
149             if (methodName.length() >= 4) {
150                 fieldName = methodName.substring(3, 4).toLowerCase()
151                         + methodName.substring(4);
152                 // 如果方法是“get方法”，並且屬性列表中包含該方法對應的屬性名
153                 if (methodName.startsWith("get")
154                         && argsList.contains(fieldName)) {
155                     // 如果為null，拋出異常
156                     if (method.invoke(t) == null) {
157                         throw new IllegalArgumentException(fieldName
158                                 + " cann‘t be null!");
159                     }
160                     // 如果該方法返回類型為String,返回結果為空字符串，拋出異常。
161                     Class<?> returnType = method.getReturnType();
162                     String returnTypeName = returnType.getSimpleName();
163                     if (returnTypeName.equals("String")
164                             && "".equals(method.invoke(t))) {
165                         throw new IllegalArgumentException(fieldName
166                                 + " cann‘t be empty String!");
167                     }
168                 }
169             }
170 
171         }
172 
173     }
174 }

利用反射機制編寫校驗參數（對象及屬性）為空的情況