BeanUtils.copyProperties复制不生效的解决

package com.hx.test03;  
import org.apache.commons.beanutils.BeanUtils; 

public class Test24BeanUtilsCopy {
 
  // Test24BeanUtilsCopy
  // 1. 取的 source 的 propertyDescriptor
  // 2. get, set 对应的类型不匹配
  public static void main(String[] args) throws Exception {
 
    Test24ImmutableEntity fromImmutable = new Test24ImmutableEntity("fromImmutable");
    Test24MutableEntity fromMutable = new Test24MutableEntity("fromMutable");
    Test24MutableEntity targetEntity = new Test24MutableEntity("targetEntity");
 
    // does't work
    BeanUtils.copyProperties(targetEntity, fromImmutable);
    System.out.println(targetEntity.getAttr());
    // does't work
    BeanUtils.copyProperties(targetEntity, fromMutable);
    System.out.println(targetEntity.getAttr()); 
  }
}
 

package com.hx.test03; 

public class Test24ImmutableEntity {
 
  // attr
  private final String attr;
 
  public Test24ImmutableEntity(String attr) {
    this.attr = attr;
  }
 
  public String getAttr() {
    return attr;
  } 
}

package com.hx.test03; 
import java.util.Optional; 

public class Test24MutableEntity {
 
  // attr
  private String attr;
 
  public Test24MutableEntity(String attr) {
    this.attr = attr;
  }
 
  public Optional<String> getAttr() {
    return Optional.of(attr);
  }
 
//  public String getAttr() {
//    return attr;
//  }
 
  public void setAttr(String attr) {
    this.attr = attr;
  } 
}

// 1. 寻找 getter(存在多个merge) 
// First pass. Find the latest getter method. Merge properties
// of previous getter methods.
 
// 2. 寻找 setter(存在多个merge) 
// Second pass. Find the latest setter method which
// has the same type as the getter method.
 
// 3. merge getter & setter 
// At this stage we should have either PDs or IPDs for the
// representative getters and setters. The order at which the
// property descriptors are determined represent the
// precedence of the property ordering.

package com.hx.test03;  
import org.apache.commons.beanutils.BeanUtils; 

public class Test23BeanUtilsCopy {
 
  // Test23BeanUtilsCopy
  // 1. 取的 source 的 propertyDescriptor
  // 2. get, set 对应的类型不匹配
  public static void main(String[] args) throws Exception { 
    ImmutableEntity fromImmutable = new ImmutableEntity("fromImmutable");
    MutableEntity fromMutable = new MutableEntity("fromMutable");
    MutableEntity targetEntity = new MutableEntity("targetEntity");
 
    // does't work
    BeanUtils.copyProperties(targetEntity, fromImmutable);
    System.out.println(targetEntity.getAttr());
    // does't work
    BeanUtils.copyProperties(targetEntity, fromMutable);
    System.out.println(targetEntity.getAttr()); 
  }
}
 

class ImmutableEntity {
  // attr
  private final String attr;
 
  public ImmutableEntity(String attr) {
    this.attr = attr;
  }
 
  public String getAttr() {
    return attr;
  }
}
 

class MutableEntity {
  // attr
  private String attr;
 
  public MutableEntity(String attr) {
    this.attr = attr;
  }
 
//  public Optional<String> getAttr() {
//    return Optional.of(attr);
//  }
  public String getAttr() {
    return attr;
  }
 
  public void setAttr(String attr) {
    this.attr = attr;
  }
}