利用反射机制编写校验参数（对象及属性）为空的情况

package com.ry.check;

import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

public class MyCheck {
    public static void main(String[] args) throws IllegalAccessException,
            IllegalArgumentException, InvocationTargetException {
        MyCheck check = new MyCheck();
        Student student = new Student();
        student.setName("zzzz");
        student.setAddress("sss");
        student.setIdno("5664");
//        student.setPhone("sss");
        check.test1(student);

    }

    public void test(Student student) throws IllegalAccessException,
            IllegalArgumentException, InvocationTargetException {
        CheckParamUtil<Student> checkParamUtil = new CheckParamUtil<Student>();
        checkParamUtil.checkParam(student);
        System.out.println("student:" + student);
    }

    public void test1(Student student) throws IllegalAccessException,
            IllegalArgumentException, InvocationTargetException {
        CheckParamUtil<Student> checkParamUtil = new CheckParamUtil<Student>();
        checkParamUtil.checkParam(student, "name", "address", "idno","phone");
        System.out.println("student:" + student);
    }

}

class Student {
    private String name;
    private int age;
    private String address;
    private String idno;
    private String phone;

    public Student() {
    }

    public Student(String name, int age, String address, String idno,
            String phone) {
        super();
        this.name = name;
        this.age = age;
        this.address = address;
        this.idno = idno;
        this.phone = phone;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }

    public String getIdno() {
        return idno;
    }

    public void setIdno(String idno) {
        this.idno = idno;
    }

    public String getPhone() {
        return phone;
    }

    public void setPhone(String phone) {
        this.phone = phone;
    }

    @Override
    public String toString() {
        return "Student [name=" + name + ", age=" + age + ", address="
                + address + ", idno=" + idno + ", phone=" + phone + "]";
    }

    public void a() {
        System.out.println("haha");
    }
}

class CheckParamUtil<T> {
    /**
     * 
     * @Title:checkParam
     * @Description:(该方法用来校验对象及其属性是否为空)
     * @param t
     * @param args
     * @author
     * @throws InvocationTargetException
     * @throws IllegalArgumentException
     * @throws IllegalAccessException
     * @修改时间：2017年6月9日 下午2:18:54
     * @修改内容：创建
     */
    public void checkParam(T t, String... args) throws IllegalAccessException,
            IllegalArgumentException, InvocationTargetException {
        // 如果传入的对象为空，则直接抛出异常
        if (t == null) {
            throw new IllegalArgumentException("This object cann't be empty!");
        }
        Class<? extends Object> clazz = t.getClass();
        // 定义属性列表
        List<String> argsList = new ArrayList<String>();
        // 如果传入的属性名不为空，则将传入的属性名放入属性列表
        if (args != null && args.length > 0) {
            argsList = Arrays.asList(args);
        } else {// 如果传入的属性名为空，则将所有属性名放入属性列表
            Field[] fields = clazz.getDeclaredFields();
            for (Field field : fields) {
                argsList.add(field.getName());
            }
        }
        // 获取该类自定义的方法数组
        Method[] methods = clazz.getDeclaredMethods();
        for (Method method : methods) {
            // 方法名
            String methodName = method.getName();
            // 获取方法对应的属性名
            String fieldName = "";
            if (methodName.length() >= 4) {
                fieldName = methodName.substring(3, 4).toLowerCase()
                        + methodName.substring(4);
                // 如果方法是“get方法”，并且属性列表中包含该方法对应的属性名
                if (methodName.startsWith("get")
                        && argsList.contains(fieldName)) {
                    // 如果为null，抛出异常
                    if (method.invoke(t) == null) {
                        throw new IllegalArgumentException(fieldName
                                + " cann't be null!");
                    }
                    // 如果该方法返回类型为String,返回结果为空字符串，抛出异常。
                    Class<?> returnType = method.getReturnType();
                    String returnTypeName = returnType.getSimpleName();
                    if (returnTypeName.equals("String")
                            && "".equals(((String)(method.invoke(t))).trim())) {
                        throw new IllegalArgumentException(fieldName
                                + " cann't be empty String!");
                    }
                }
            }

        }

    }
}

package com.ry.check;
import java.lang.reflect.Field;import java.lang.reflect.InvocationTargetException;import java.lang.reflect.Method;import java.util.ArrayList;import java.util.Arrays;import java.util.List;
public class MyCheck {public static void main(String[] args) throws IllegalAccessException,IllegalArgumentException, InvocationTargetException {MyCheck check = new MyCheck();Student student = new Student();student.setName("zzzz");student.setAddress("sss");student.setIdno("5664");//student.setPhone("sss");check.test1(student);
}
public void test(Student student) throws IllegalAccessException,IllegalArgumentException, InvocationTargetException {CheckParamUtil<Student> checkParamUtil = new CheckParamUtil<Student>();checkParamUtil.checkParam(student);System.out.println("student:" + student);}
public void test1(Student student) throws IllegalAccessException,IllegalArgumentException, InvocationTargetException {CheckParamUtil<Student> checkParamUtil = new CheckParamUtil<Student>();checkParamUtil.checkParam(student, "name", "address", "idno","phone");System.out.println("student:" + student);}
}
class Student {private String name;private int age;private String address;private String idno;private String phone;
public Student() {}
public Student(String name, int age, String address, String idno,String phone) {super();this.name = name;this.age = age;this.address = address;this.idno = idno;this.phone = phone;}
public String getName() {return name;}
public void setName(String name) {this.name = name;}
public int getAge() {return age;}
public void setAge(int age) {this.age = age;}
public String getAddress() {return address;}
public void setAddress(String address) {this.address = address;}
public String getIdno() {return idno;}
public void setIdno(String idno) {this.idno = idno;}
public String getPhone() {return phone;}
public void setPhone(String phone) {this.phone = phone;}
@Overridepublic String toString() {return "Student [name=" + name + ", age=" + age + ", address="+ address + ", idno=" + idno + ", phone=" + phone + "]";}
public void a() {System.out.println("haha");}}
class CheckParamUtil<T> {/** *  * @Title:checkParam * @Description:(该方法用来校验对象及其属性是否为空) * @param t * @param args * @author * @throws InvocationTargetException * @throws IllegalArgumentException * @throws IllegalAccessException * @修改时间：2017年6月9日 下午2:18:54 * @修改内容：创建 */public void checkParam(T t, String... args) throws IllegalAccessException,IllegalArgumentException, InvocationTargetException {// 如果传入的对象为空，则直接抛出异常if (t == null) {throw new IllegalArgumentException("This object cann't be empty!");}Class<? extends Object> clazz = t.getClass();// 定义属性列表List<String> argsList = new ArrayList<String>();// 如果传入的属性名不为空，则将传入的属性名放入属性列表if (args != null && args.length > 0) {argsList = Arrays.asList(args);} else {// 如果传入的属性名为空，则将所有属性名放入属性列表Field[] fields = clazz.getDeclaredFields();for (Field field : fields) {argsList.add(field.getName());}}// 获取该类自定义的方法数组Method[] methods = clazz.getDeclaredMethods();for (Method method : methods) {// 方法名String methodName = method.getName();// 获取方法对应的属性名String fieldName = "";if (methodName.length() >= 4) {fieldName = methodName.substring(3, 4).toLowerCase()+ methodName.substring(4);// 如果方法是“get方法”，并且属性列表中包含该方法对应的属性名if (methodName.startsWith("get")&& argsList.contains(fieldName)) {// 如果为null，抛出异常if (method.invoke(t) == null) {throw new IllegalArgumentException(fieldName+ " cann't be null!");}// 如果该方法返回类型为String,返回结果为空字符串，抛出异常。Class<?> returnType = method.getReturnType();String returnTypeName = returnType.getSimpleName();if (returnTypeName.equals("String")&& "".equals(((String)(method.invoke(t))).trim())) {throw new IllegalArgumentException(fieldName+ " cann't be empty String!");}}}
}
}}