Mybatis BeanUtil 日期报错

org.apache.commons.beanutils.ConversionException: DateConverter does not support default String to 'Date' conversion.
报错控制台：

hrf
八月 24, 2017 10:49:12 上午 org.apache.commons.beanutils.converters.DateTimeConverter toDate
警告:     DateConverter does not support default String to 'Date' conversion.
八月 24, 2017 10:49:12 上午 org.apache.commons.beanutils.converters.DateTimeConverter toDate
警告:     (N.B. Re-configure Converter or use alternative implementation)

这个错，或许不是代码问题，我也找了挺久的，是导入错了包，把 import  java.sql.Date-->import java.util.Date

改后控制台:
hrf
Tue May 14 00:00:00 CST 1996

注意:

转换日期（定义转换器）:

1.创建一个类让其实现Convert接口

2.覆盖这个接口的Convert方法，在这个方法中实现转换

3.在拷贝之前，必须注册转换器

package com.amaker.bean;

import java.util.Date;
public class User {
private int id;
private String username;
private int age;
private Date born;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public Date getBorn() {
return born;
}
public void setBorn(Date born) {
this.born = born;
}

}

package com.amaker.bean;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.sql.Date;
import org.apache.commons.beanutils.Converter;
public class DateConverter implements Converter{
  SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd");

       //该方法中的两个参数，第一个参数表示要转换的类型，如果要拷贝一个字符串到日期中，此时这就是日期类型，第二个参数表示要转换的值，该方法的值就是要转换的值。
@Override
public Object convert(Class cls, Object value) {
if(cls!=Date.class){
return null;
}
if(value instanceof String){
try {
return sdf.parse((String)value);
} catch (ParseException e) {
e.printStackTrace();}
}
return null;}

}

package com.amaker.bean;
import static org.junit.Assert.*;
import java.lang.reflect.InvocationTargetException;
import java.sql.Date;
import org.apache.commons.beanutils.BeanUtils;
import org.apache.commons.beanutils.ConvertUtils;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;

public class TestUtil {
@Test
public void test() {
User u=new User();
try {
BeanUtils.copyProperty(u, "username", "hrf");
System.out.println(u.getUsername());
ConvertUtils.register(new DateConverter(),Date.class);
BeanUtils.copyProperty(u,"born", "1996-05-14");
System.out.println(u.getBorn());
} catch (IllegalAccessException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (InvocationTargetException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}