参考http://blog.sina.com.cn/s/blog_7ffb8dd50101aoxd.html

与反射，自己定义对比https://blog.csdn.net/Darrensty/article/details/78395221

场景:

系统中一般都要打印日志的，因为所有实体的toString()方法 都用的是简单的"+"，因为每"＋" 一个就会 new 一个 String 对象，这样如果系统内存小的话会暴内存（前提系统实体比较多）。使用ToStringBuilder就可以避免暴内存这种问题的。 

注意:

ToStringBuilder、HashCodeBuilder、EqualsBuilder、ToStringStyle、ReflectionToStringBuilder、CompareToBuilder等这些类都是位于commons-lang3.jar下面的，所以要使用这些类一定要导入commons-lang3(jar)

ToStringBuilder的append方法

用于类的格式化输出。ToStringBuilder中append方法可以向该类添加基本类型、数组、和对象，只有添加的方法才会被toString输出。如：

class TaxReturn {
  private String ssn;
  private int year;
  private String lastName;
  private BigDecimal taxableIncome;
  // get/set方法省略
  public TaxReturn() {
  }
 public TaxReturn(String pSsn, int pYear, String pLastName, BigDecimal pTaxableIncome) { 
    setSsn(pSsn); 
    setYear(pYear); 
    setLastName(pLastName); 
    setTaxableIncome(pTaxableIncome); 
  } 
  public String toString() {
    return new ToStringBuilder(this).append("ssn", ssn).append("year", year).append("lastName",
        lastName).toString();
  }

  public int hashCode() {
    return new HashCodeBuilder(3, 7).append(ssn).append(year).toHashCode();
  }

  public boolean equals(Object pObject) {
    boolean equals = false;
    if (pObject instanceof TaxReturn) {
      TaxReturn bean = (TaxReturn) pObject;
      equals = (new EqualsBuilder().append(ssn, bean.ssn).append(year, bean.year)).isEquals();
    }
    return equals;
  }

  public int compareTo(Object pObject) {
    return CompareToBuilder.reflectionCompare(this, pObject);
  }

}

public class MainClass {

  public static void main(String[] pArgs) throws Exception {
     TaxReturn return1 = new TaxReturn("012-68-3242", 1998, "O'Brien", new BigDecimal(43000.00));
     TaxReturn return2 = new TaxReturn("012-68-3242", 1999, "O'Brien", new BigDecimal(45000.00));
     TaxReturn return3 = new TaxReturn("012-68-3242", 1999, "O'Brien", new BigDecimal(53222.00));
     System.out.println("ToStringBuilder: " + return1.toString());
  }
}
运行结果如下：
   ToStringBuilder: TaxReturn@1503a3[ssn=012-68-3242,year=1998,lastName=O'Brien]

reflectionToString方法

把类对应的基本属性和值输出来

package other;

import org.apache.commons.lang3.builder.ToStringBuilder;

import java.io.Serializable;

/**
 * 父类重写了reflectionToString
 */
public class Entitys implements Serializable {
    private static final long serialVersionUID = 1L;

    @Override
    public String toString() {
        return ToStringBuilder.reflectionToString(this);
    }
}


package other;

import java.io.Serializable;

/**
 * Created by Administrator on 2019/3/5/005.
 */
public class User extends Entitys implements Serializable {
    private static final long serialVersionUID = 1L;

    private String name;
    private int age ;

    public User(String name, int age) {
        this.name = name;
        this.age = age;
    }
}

package other;


public class Test {
    public static void main(String []args){
        User user1 = new User("CXY",22);
        User user2 = new User("wang",22);
        System.out.println("1>>>" + user1);
        System.out.println("2>>>" + user2);
    }
}

 DEFAULT_STYLE （默认）

     MULTI_LINE_STYLE  （分行）

 NO_FIELD_NAMES_STYLE （没有name,age）

 SHORT_PREFIX_STYLE   （即截去了包名others）
 
SIMPLE_STYLE  (CXY,22)