@Data
public class SourceBean {
    private Long age;
}
@Data
public class TargetBean {
    private String age;
}
public class Test {
    public static void main(String[] args) {
        SourceBean source = new SourceBean();
        source.setAge(25L);
        TargetBean target = new TargetBean();
        BeanUtils.copyProperties(source, target);
        System.out.println(target.getAge());  //拷貝賦值失敗，輸出null
    }
}

public class Address {
    private String city;
    //getter 和 setter 方法省略
}
public class Person {
    private String name;
    private Address address;
    //getter 和 setter 方法省略
}
 Person sourcePerson = new Person();
 sourcePerson.setName("John");
 Address address = new Address();
 address.setCity("New York");
 sourcePerson.setAddress(address);
 Person targetPerson = new Person();
 BeanUtils.copyProperties(sourcePerson, targetPerson);
 sourcePerson.getAddress().setCity("London");
 System.out.println(targetPerson.getAddress().getCity());  // 輸出為 "London"

 public class SourceBean {
    private String username;
    // getter 和 setter 方法省略
}
public class TargetBean {
    private String userName;
    // getter 和 setter 方法省略
}
 SourceBean source = new SourceBean();
 source.setUsername("撿田螺的小男孩");
 TargetBean target = new TargetBean();
 BeanUtils.copyProperties(source, target);
 System.out.println(target.getUserName());   // 輸出為 null

@Data
public class SourceBean {
    private String name;
    private String address;
}
@Data
public class TargetBean {
    private String name;
    private String address;
}
SourceBean source = new SourceBean();
source.setName("John");
source.setAddress(null);
TargetBean target = new TargetBean();
target.setAddress("田螺address");
BeanUtils.copyProperties(source, target);
System.out.println(target.getAddress());  // 輸出為 null

//org.springframework.beans.BeanUtils(源對(duì)象在左邊，目標(biāo)對(duì)象在右邊)
public static void copyProperties(Object source, Object target) throws BeansException 
//org.apache.commons.beanutils.BeanUtils（源對(duì)象在右邊，目標(biāo)對(duì)象在左邊）
public static void copyProperties(Object dest, Object orig) throws IllegalAccessException, InvocationTargetException

@Data
public class SourceBean {
    private boolean isTianLuo;
}
@Data
public class TargetBean {
    private Boolean isTianLuo;
}

SourceBean source = new SourceBean();
source.setTianLuo(true);
TargetBean target = new TargetBean();
BeanUtils.copyProperties(source, target);
System.out.println(target.getIsTianLuo()); // 輸出為 null

@Data
public class CopySource {
    public String outerName;
    public CopySource.InnerClass innerClass;
    @Data
    public static class InnerClass {
        public String InnerName;
    }
}
@Data
public class CopyTarget {
    public String outerName;
    public CopyTarget.InnerClass innerClass;
    @Data
   public static class InnerClass {
        public String InnerName;
    }
}
CopySource test1 = new CopySource();
test1.outerName = "outTianluo";
CopySource.InnerClass innerClass = new CopySource.InnerClass();
innerClass.InnerName = "innerTianLuo";
test1.innerClass = innerClass;
System.out.println(test1);
CopyTarget test2 = new CopyTarget();
BeanUtils.copyProperties(test1, test2);
System.out.println(test2);  //輸出CopyTarget(outerName=outTianluo, innerClass=null)

@Data
public class SourceBean {
    private String value;
}
@Getter   //沒(méi)有對(duì)應(yīng)的setter方法
public class TargetBean {
    private String value;
}
SourceBean source = new SourceBean();
source.setValue("撿田螺的小男孩");
TargetBean target = new TargetBean();
BeanUtils.copyProperties(source, target);
System.out.println(target.getValue()); //輸出null 

@Data
public class CopySource {
    public String outerName;
    public List<CopySource.InnerClass> clazz;
    @Data
    public static class InnerClass {
        public String InnerName;
    }
}
@ToString
@Data
public class CopyTarget {
    public String outerName;
    public List<CopyTarget.InnerClass> clazz;
    @Data
    public static class InnerClass {
        public String InnerName;
    }
}
CopySource test1 = new CopySource();
test1.outerName = "outTianluo";
CopySource.InnerClass innerClass = new CopySource.InnerClass();
innerClass.InnerName = "innerTianLuo";
List<CopySource.InnerClass> clazz = new ArrayList<>();
clazz.add(innerClass);
test1.setClazz(clazz);
System.out.println(test1);
CopyTarget test2 = new CopyTarget();
BeanUtils.copyProperties(test1, test2);
System.out.println(test2);  //輸出CopyTarget(outerName=outTianluo, clazz=null)

SourceBean sourceBean = new SourceBean();
sourceBean.setName("tianLuoBoy");
TargetBean target = new TargetBean();
long beginTime = System.currentTimeMillis();
for (int i = 0; i < 100000; i++) {  //循環(huán)10萬(wàn)次
      target.setName(sourceBean.getName());
}
System.out.println("common setter time:" + (System.currentTimeMillis() - beginTime));
long beginTime1 = System.currentTimeMillis();
for (int i = 0; i < 100000; i++) {  //循環(huán)10萬(wàn)次
    BeanUtils.copyProperties(sourceBean, target);
}
System.out.println("bean copy time:" + (System.currentTimeMillis() - beginTime1));
//輸出
common setter time:3
bean copy time:331