javaBeans 属性的概念

不只是字段，而是其get set 方法

且该get方法有返回值的称为属性，继承Object类的getClass方法

package com.swift.demo1;public class Person {    String name;    int age;    String password;    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 getPassword() {        return password;    }    public void setPassword(String password) {        this.password = password;    }    public String getAd() {
   //这个算一个属性，虽让没有字段，但如果没有返回值不算一个属性        return "getAd.....";    }}

属性个数

package com.swift.demo1;import java.beans.BeanInfo;import java.beans.Introspector;import java.beans.PropertyDescriptor;import org.junit.jupiter.api.Test;public class TestIntro {    @Test    public void test1() throws Exception {        BeanInfo info=Introspector.getBeanInfo(Person.class);        PropertyDescriptor[] pds=info.getPropertyDescriptors();        for(PropertyDescriptor des:pds) {            System.out.println(des.getName());        }    }}

阻止父类的getClass属性用

package com.swift.demo1;import java.beans.BeanInfo;import java.beans.Introspector;import java.beans.PropertyDescriptor;import org.junit.jupiter.api.Test;public class TestIntro {    @Test    public void test1() throws Exception {        BeanInfo info=Introspector.getBeanInfo(Person.class,Object.class);        PropertyDescriptor[] pds=info.getPropertyDescriptors();        for(PropertyDescriptor des:pds) {            System.out.println(des.getName());        }    }}

 

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BeanUtils使用jar包

需要两个：

都可以在Apache网站下载

BeanUtils具有比Introspector更强大的功能，可以在基本数据类型间直接转换，也可以把文本框中的字符串通过注册器转换器进行转换

自己转日期格式

package com.swift.demo1;import java.lang.reflect.InvocationTargetException;import java.text.ParseException;import java.text.SimpleDateFormat;import java.util.Date;import org.apache.commons.beanutils.BeanUtils;import org.apache.commons.beanutils.ConvertUtils;import org.apache.commons.beanutils.Converter;import org.junit.Test;public class TestUtils {    @Test    public void test() throws IllegalAccessException, InvocationTargetException, NoSuchMethodException {                Person p=new Person();                ConvertUtils.register(new Converter() {            @Override            public Object convert(Class type, Object value) {                String str=(String) value;                SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd");                try {                    return sdf.parse(str);                } catch (ParseException e) {                    throw new RuntimeException(e);//                }            }        }, Date.class);                BeanUtils.setProperty(p, "name", "swift");        BeanUtils.setProperty(p, "age", "30");        BeanUtils.setProperty(p, "password", "123");        BeanUtils.setProperty(p, "date", "2018-02-19");                System.out.println(p.getName());        System.out.println(BeanUtils.getProperty(p, "name"));        System.out.println(BeanUtils.getProperty(p, "age"));        System.out.println(BeanUtils.getProperty(p, "password"));        System.out.println(BeanUtils.getProperty(p, "date"));    }}

可以用现成的

package com.swift.demo1;import java.lang.reflect.InvocationTargetException;import java.util.Date;import org.apache.commons.beanutils.BeanUtils;import org.apache.commons.beanutils.ConvertUtils;import org.apache.commons.beanutils.locale.converters.DateLocaleConverter;import org.junit.Test;public class TestUtils {    @Test    public void test() throws IllegalAccessException, InvocationTargetException, NoSuchMethodException {                Person p=new Person();                ConvertUtils.register(new DateLocaleConverter(),Date.class);                BeanUtils.setProperty(p, "name", "swift");        BeanUtils.setProperty(p, "age", "30");        BeanUtils.setProperty(p, "password", "123");        BeanUtils.setProperty(p, "date", "2018-02-19");                System.out.println(p.getName());        System.out.println(BeanUtils.getProperty(p, "name"));        System.out.println(BeanUtils.getProperty(p, "age"));        System.out.println(BeanUtils.getProperty(p, "password"));        System.out.println(BeanUtils.getProperty(p, "date"));    }}

集合map加到BeanUtils

package com.swift.demo1;import java.lang.reflect.InvocationTargetException;import java.util.Date;import java.util.HashMap;import java.util.Map;import org.apache.commons.beanutils.BeanUtils;import org.apache.commons.beanutils.ConvertUtils;import org.apache.commons.beanutils.locale.converters.DateLocaleConverter;import org.junit.Test;public class TestUtils {    @Test    public void test() throws IllegalAccessException, InvocationTargetException, NoSuchMethodException {                Person p=new Person();                ConvertUtils.register(new DateLocaleConverter(),Date.class);                BeanUtils.setProperty(p, "name", "swift");        BeanUtils.setProperty(p, "age", "30");        BeanUtils.setProperty(p, "password", "123");        BeanUtils.setProperty(p, "date", "2018-02-19");                System.out.println(p.getName());        System.out.println(BeanUtils.getProperty(p, "name"));        System.out.println(BeanUtils.getProperty(p, "age"));        System.out.println(BeanUtils.getProperty(p, "password"));        System.out.println(BeanUtils.getProperty(p, "date"));    }        @Test    public void test1() throws IllegalAccessException, InvocationTargetException, NoSuchMethodException {                Person p=new Person();                ConvertUtils.register(new DateLocaleConverter(),Date.class);                Map
     
       map=new HashMap
      
       ();        map.put("name", "swift");        map.put("age", "30");        map.put("password", "123");        map.put("date", "2018-02-19");                BeanUtils.populate(p, map);                System.out.println(p.getName());        System.out.println(BeanUtils.getProperty(p, "name"));        System.out.println(BeanUtils.getProperty(p, "age"));        System.out.println(BeanUtils.getProperty(p, "password"));        System.out.println(BeanUtils.getProperty(p, "date"));    }}