JavaBean
Bean的属性，字段对外提供了get或set方法那这个字段叫做属性，一个bean的属性不是由字段决定的，而是由get或set方法决定，只要有相对应的get或set方法就会有相对应的属性
内省
import java.beans.BeanInfo;
import java.beans.Introspector;
import java.beans.PropertyDescriptor;
import java.lang.reflect.Method;
import org.junit.Test;
public class Demo1 {
@Test
public void test1() throws Exception {
BeanInfo info =Introspector.getBeanInfo(Person.class,Object.class);
PropertyDescriptor[] pds = info.getPropertyDescriptors();
for (PropertyDescriptor ps : pds) {
System.out.println(ps.getName());
}
}
//操纵bean的指定属性：age
@Test
public void test2() throws Exception{
Person p=new Person();
PropertyDescriptor pd=newPropertyDescriptor("age",Person.class);
//得到属性的写方法，为属性赋值
Method method=pd.getWriteMethod();
method.invoke(p, 45);
//获取属性的值
method=pd.getReadMethod();
System.out.println(method.invoke(p,null));
}
@Test
public void test3() throws Exception{
Person p=new Person();
PropertyDescriptor pd=newPropertyDescriptor("age",Person.class);
System.out.println(pd.getPropertyType());
}
}
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;
importorg.apache.commons.beanutils.BeanUtils;
importorg.apache.commons.beanutils.ConversionException;
importorg.apache.commons.beanutils.ConvertUtils;
importorg.apache.commons.beanutils.Converter;
importorg.apache.commons.beanutils.locale.converters.DateLocaleConverter;
import org.junit.Test;
public class Demo1 {
@Test
public void test1() throws Exception{
Person p=new Person();
BeanUtils.setProperty(p," name", "nannan");
System.out.println(BeanUtils.getProperty(p,"name"));
}
@Test
public void test2() throws Exception,Exception{
String birthday="1990-06-01";
Person p=new Person();
//为了让日期赋值到birthday属性上，我们给beanUtils注册一个日期转换器
ConvertUtils.register(new Converter(){
@Override
public Object convert(Class type, Object value) {
if(value==null){
return null;
}
if(!(value instanceof String)){
throw new ConversionException("只支持String类型的转换");
}
String str=(String)value;
if(str.trim().equals(" ")){
return null;
}
SimpleDateFormat df=new SimpleDateFormat("yyyy-MM-dd");
try {
return df.parse(str);
} catch (ParseException e) {
throw new RuntimeException(e);//异常链不能断
}
}
}, Date.class);
//Date date=p.getBirthday();
BeanUtils.setProperty(p, "birthday", birthday);
Date date=p.getBirthday();
System.out.println(date.toLocaleString());
}
@Test
public void test3() throws Exception{
String birthday="1990-06-01";
ConvertUtils.register(new DateLocaleConverter(),Date.class);
Person p=new Person();
BeanUtils.setProperty(p, "birthday", birthday);
System.out.println(p.getBirthday().toLocaleString());
}
@Test
public void test4() throws Exception{
Map map=new HashMap();
map.put("name", "aaa");
map.put("password","123" );
map.put("birthday","1990-06-01");
ConvertUtils.register(new DateLocaleConverter(),Date.class);
Person bean=new Person();
BeanUtils.populate(bean, map);//用map集合中的值填充bean的属性
System.out.println(bean.getBirthday().toLocaleString());
System.out.println(bean.getName());
System.out.println(bean.getPassword());
}
}
