org.springframework.beans.BeanUtils学习笔记
注:转自:https://www.cnblogs.com/dongfangshenhua/p/7099970.html
仅仅只是拿来作为笔记,方便以后自己查看。
知识点
org.springframework.beans.BeanUtils与org.apache.commons.beanutils.BeanUtils都提供了copyProperties方法,作用是将一个Bean对象中的数据封装到另一个属性结构相似的Bean对象中
1)两者的copyProperties方法参数位置不同
org.springframework.beans.BeanUtils: copyProperties(sourceDemo, targetDemo)
org.apache.commons.beanutils.BeanUtils: copyProperties(targetDemo, sourceDemo)
2)要求两个Bean的属性名相同,且有对应的setXxx方法和getXxx方法。其实底层原理是使用sourceDemo的getXxx方法和targetDemo的setXxx方法
3)sourceDemo有的属性而targetDemo没有的属性,不会封装到targetDemo对象中;
targetDemo有的属性而sourceDemo没有的属性,会封装到targetDemo中,数据为默认值(注意基本类型默认值与引用类型默认值不同)
4)类型转换问题
a)基本类型与其对应的封装类型可以相互转换
b)org.springframework.beans.BeanUtils与org.apache.commons.beanutils.BeanUtils对于String和Date类型转换的情况是不同的,具体看以下案例
案例一
SourceDemo
package com.fortis.customer.test;
import java.util.Date;
import org.apache.commons.lang3.builder.ToStringBuilder;
public class SourceDemo {
private int id;
private String name;
private String address;
private Date createTime;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
public Date getCreateTime() {
return createTime;
}
public void setCreateTime(Date createTime) {
this.createTime = createTime;
}
@Override
public String toString() {
return ToStringBuilder.reflectionToString(this);
}
}
TargetDemo
package com.fortis.customer.test;
import java.util.Date;
import org.apache.commons.lang3.builder.ToStringBuilder;
public class TargetDemo {
private Integer id;
private String name;
private String email;
private Date createTime;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
public Date getCreateTime() {
return createTime;
}
public void setCreateTime(Date createTime) {
this.createTime = createTime;
}
@Override
public String toString() {
return ToStringBuilder.reflectionToString(this);
}
}
Test
package com.fortis.customer.test;
import java.lang.reflect.InvocationTargetException;
import java.util.Date;
public class Test {
public static void main(String[] args) throws IllegalAccessException, InvocationTargetException {
SourceDemo sourceDemo = new SourceDemo();
sourceDemo.setId(10);
sourceDemo.setName("姓名");
sourceDemo.setAddress("地址");
sourceDemo.setCreateTime(new Date());
TargetDemo targetDemo = new TargetDemo();
org.springframework.beans.BeanUtils.copyProperties(sourceDemo, targetDemo);
System.out.println(targetDemo);
org.apache.commons.beanutils.BeanUtils.copyProperties(targetDemo, sourceDemo);
System.out.println(targetDemo);
}
}
测试效果:
[id=10,name=姓名,email=<null>,createTime=Fri Jun 30 16:19:31 CST 2017]
[id=10,name=姓名,email=<null>,createTime=Fri Jun 30 16:19:31 CST 2017]
结论:基本类型与其对应的封装类型是可以相互转换的
案例二
SourceDemo
package com.fortis.customer.test;
import java.util.Date;
import org.apache.commons.lang3.builder.ToStringBuilder;
public class SourceDemo {
private int id;
private String name;
private String address;
private Date createTime;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
public Date getCreateTime() {
return createTime;
}
public void setCreateTime(Date createTime) {
this.createTime = createTime;
}
@Override
public String toString() {
return ToStringBuilder.reflectionToString(this);
}
}
TargetDemo
package com.fortis.customer.test;
import org.apache.commons.lang3.builder.ToStringBuilder;
public class TargetDemo {
private Integer id;
private String name;
private String email;
private String createTime;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
public String getCreateTime() {
return createTime;
}
public void setCreateTime(String createTime) {
this.createTime = createTime;
}
@Override
public String toString() {
return ToStringBuilder.reflectionToString(this);
}
}
Test
package com.fortis.customer.test;
import java.lang.reflect.InvocationTargetException;
import java.util.Date;
public class Test {
public static void main(String[] args) throws IllegalAccessException, InvocationTargetException {
SourceDemo sourceDemo = new SourceDemo();
sourceDemo.setId(10);
sourceDemo.setName("姓名");
sourceDemo.setAddress("地址");
sourceDemo.setCreateTime(new Date(0));
TargetDemo targetDemo = new TargetDemo();
org.springframework.beans.BeanUtils.copyProperties(sourceDemo, targetDemo);
System.out.println(targetDemo);
//org.apache.commons.beanutils.BeanUtils.copyProperties(targetDemo, sourceDemo);
//System.out.println(targetDemo);
}
}
测试效果:
Exception in thread "main" org.springframework.beans.FatalBeanException: Could not copy properties from source to target; nested exception is java.lang.IllegalArgumentException: argument type mismatch
at org.springframework.beans.BeanUtils.copyProperties(BeanUtils.java:599)
at org.springframework.beans.BeanUtils.copyProperties(BeanUtils.java:509)
at com.fortis.customer.test.Test.main(Test.java:17)
Caused by: java.lang.IllegalArgumentException: argument type mismatch
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.springframework.beans.BeanUtils.copyProperties(BeanUtils.java:596)
... 2 more
结论:org.springframework.beans.BeanUtils.copyProperties不可以将java.util.Date类型转换成String类型
同时:也不可将java.sql.Date类型转换成String类型(因为网上搜的说可以支持java.sql.Date类型,我自己测试了一下发现不可以,还是信自己靠谱)
Exception in thread "main" org.springframework.beans.FatalBeanException: Could not copy properties from source to target; nested exception is java.lang.IllegalArgumentException: argument type mismatch
at org.springframework.beans.BeanUtils.copyProperties(BeanUtils.java:599)
at org.springframework.beans.BeanUtils.copyProperties(BeanUtils.java:509)
at com.fortis.customer.test.Test.main(Test.java:17)
Caused by: java.lang.IllegalArgumentException: argument type mismatch
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.springframework.beans.BeanUtils.copyProperties(BeanUtils.java:596)
... 2 more
案例三
Test
package com.fortis.customer.test;
import java.lang.reflect.InvocationTargetException;
import java.util.Date;
public class Test {
public static void main(String[] args) throws IllegalAccessException, InvocationTargetException {
SourceDemo sourceDemo = new SourceDemo();
sourceDemo.setId(10);
sourceDemo.setName("姓名");
sourceDemo.setAddress("地址");
sourceDemo.setCreateTime(new Date(0));
TargetDemo targetDemo = new TargetDemo();
//org.springframework.beans.BeanUtils.copyProperties(sourceDemo, targetDemo);
//System.out.println(targetDemo);
org.apache.commons.beanutils.BeanUtils.copyProperties(targetDemo, sourceDemo);
System.out.println(targetDemo);
}
}
注:SourceDemo和TargetDemo与案例二相同
测试效果:java.util.Date
[id=10,name=姓名,email=<null>,createTime=Thu Jan 01 08:00:00 CST 1970]
结论:org.apache.commons.beanutils.BeanUtils.copyProperties可以将java.util.Date类型转换成String类型
测试效果:java.sql.Date
[id=10,name=姓名,email=<null>,createTime=1970-01-01]
结论:org.apache.commons.beanutils.BeanUtils.copyProperties可以将java.sql.Date类型转换成String类型
注意:虽然都可以转换,但发现两者的日期格式还是不同的
案例四:
SourceDemo
package com.fortis.customer.test;
import org.apache.commons.lang3.builder.ToStringBuilder;
public class SourceDemo {
private int id;
private String name;
private String address;
private String createTime;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
public String getCreateTime() {
return createTime;
}
public void setCreateTime(String createTime) {
this.createTime = createTime;
}
@Override
public String toString() {
return ToStringBuilder.reflectionToString(this);
}
}
TargetDemo
package com.fortis.customer.test;
import java.util.Date;
import org.apache.commons.lang3.builder.ToStringBuilder;
public class TargetDemo {
private Integer id;
private String name;
private String email;
private Date createTime;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
public Date getCreateTime() {
return createTime;
}
public void setCreateTime(Date createTime) {
this.createTime = createTime;
}
@Override
public String toString() {
return ToStringBuilder.reflectionToString(this);
}
}
Test
package com.fortis.customer.test;
import java.lang.reflect.InvocationTargetException;
import java.text.SimpleDateFormat;
import java.util.Date;
public class Test {
public static void main(String[] args) throws IllegalAccessException, InvocationTargetException {
SourceDemo sourceDemo = new SourceDemo();
sourceDemo.setId(10);
sourceDemo.setName("姓名");
sourceDemo.setAddress("地址");
sourceDemo.setCreateTime(new SimpleDateFormat("yyyyMMddHHmmss").format(new Date(0)));
TargetDemo targetDemo = new TargetDemo();
org.springframework.beans.BeanUtils.copyProperties(sourceDemo, targetDemo);
System.out.println(targetDemo);
//org.apache.commons.beanutils.BeanUtils.copyProperties(targetDemo, sourceDemo);
//System.out.println(targetDemo);
}
}
测试效果:
Exception in thread "main" org.springframework.beans.FatalBeanException: Could not copy properties from source to target; nested exception is java.lang.IllegalArgumentException: argument type mismatch
at org.springframework.beans.BeanUtils.copyProperties(BeanUtils.java:599)
at org.springframework.beans.BeanUtils.copyProperties(BeanUtils.java:509)
at com.fortis.customer.test.Test.main(Test.java:18)
Caused by: java.lang.IllegalArgumentException: argument type mismatch
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.springframework.beans.BeanUtils.copyProperties(BeanUtils.java:596)
... 2 more
结论:org.springframework.beans.BeanUtils.copyProperties不可以将String类型转换成java.util.Date类型
同时:也不可将String类型转换成java.sql.Date类型
案例五
Test
package com.fortis.customer.test;
import java.lang.reflect.InvocationTargetException;
import java.text.SimpleDateFormat;
import java.util.Date;
public class Test {
public static void main(String[] args) throws IllegalAccessException, InvocationTargetException {
SourceDemo sourceDemo = new SourceDemo();
sourceDemo.setId(10);
sourceDemo.setName("姓名");
sourceDemo.setAddress("地址");
sourceDemo.setCreateTime(new SimpleDateFormat("yyyyMMddHHmmss").format(new Date(0)));
TargetDemo targetDemo = new TargetDemo();
//org.springframework.beans.BeanUtils.copyProperties(sourceDemo, targetDemo);
//System.out.println(targetDemo);
org.apache.commons.beanutils.BeanUtils.copyProperties(targetDemo, sourceDemo);
System.out.println(targetDemo);
}
}
测试效果:java.util.Date
log4j:WARN No appenders could be found for logger (org.apache.commons.beanutils.converters.BooleanConverter).
log4j:WARN Please initialize the log4j system properly.
Exception in thread "main" org.apache.commons.beanutils.ConversionException: DateConverter does not support default String to 'Date' conversion.
at org.apache.commons.beanutils.converters.DateTimeConverter.toDate(DateTimeConverter.java:468)
at org.apache.commons.beanutils.converters.DateTimeConverter.convertToType(DateTimeConverter.java:343)
at org.apache.commons.beanutils.converters.AbstractConverter.convert(AbstractConverter.java:156)
at org.apache.commons.beanutils.converters.ConverterFacade.convert(ConverterFacade.java:60)
at org.apache.commons.beanutils.BeanUtilsBean.convert(BeanUtilsBean.java:1078)
at org.apache.commons.beanutils.BeanUtilsBean.copyProperty(BeanUtilsBean.java:437)
at org.apache.commons.beanutils.BeanUtilsBean.copyProperties(BeanUtilsBean.java:286)
at org.apache.commons.beanutils.BeanUtils.copyProperties(BeanUtils.java:137)
at com.fortis.customer.test.Test.main(Test.java:21)
结论:org.apache.commons.beanutils.BeanUtils
看错误日志,发现说是默认的转换器是不可以将String类型转换成java.util.Date,可能自己配置一个转换器就可以转了吧,我没有测试过
测试效果:java.sql.Date
log4j:WARN No appenders could be found for logger (org.apache.commons.beanutils.converters.BooleanConverter).
log4j:WARN Please initialize the log4j system properly.
Exception in thread "main" org.apache.commons.beanutils.ConversionException: String must be in JDBC format [yyyy-MM-dd] to create a java.sql.Date
at org.apache.commons.beanutils.converters.DateTimeConverter.toDate(DateTimeConverter.java:436)
at org.apache.commons.beanutils.converters.DateTimeConverter.convertToType(DateTimeConverter.java:343)
at org.apache.commons.beanutils.converters.AbstractConverter.convert(AbstractConverter.java:156)
at org.apache.commons.beanutils.converters.ConverterFacade.convert(ConverterFacade.java:60)
at org.apache.commons.beanutils.BeanUtilsBean.convert(BeanUtilsBean.java:1078)
at org.apache.commons.beanutils.BeanUtilsBean.copyProperty(BeanUtilsBean.java:437)
at org.apache.commons.beanutils.BeanUtilsBean.copyProperties(BeanUtilsBean.java:286)
at org.apache.commons.beanutils.BeanUtils.copyProperties(BeanUtils.java:137)
at com.fortis.customer.test.Test.main(Test.java:21)
结论:org.apache.commons.beanutils.BeanUtils
看错误日志,发现说是需要将String类型转成java.sql.Date,使用simpleDateFormat是将String类型转成java.util.Date,可能转成java.sql.Date就可以了吧,我没测试过
注意:我这里说的转换,单纯是指这一行代码sourceDemo.setCreateTime(new SimpleDateFormat("yyyyMMddHHmmss").format(new Date(0)));而不是两个Bean的类型转换
总之,无论是org.springframework.beans.BeanUtils还是org.apache.commons.beanutils.BeanUtils,默认情况下都不能将String类型转成Date类型
案例六:
SourceDemo:
private String name;
TargetDemo:
private String name = “马超”;
private String email = "张飞";
复制之后的结果:name = null,email = “张飞”
SourceDemo:
private String name = “诸葛亮”;
TargetDemo:
private String name = “马超”;
private String email = "张飞";
复制之后的结果:name = “诸葛亮”,email = “张飞”
注:使用两种BeanUtils效果相同
posted on 2019-03-18 11:54 AHRI-9245 阅读(4247) 评论(0) 编辑 收藏 举报