ToStringHelper of Guava

In Java, toString() method is useful for debugging. It can print the object information in human readable format. Member variables and state can be returned. Only painful stuff of toString() is that we need to implement by ourselves for custom class.

class User {
  private final String name;
  private final int    age;

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

  @Override
  public String toString() {
    return "User{name=" + name + ",age=" + age + "}"
  }
}

Formatting the string returned by toString() is painful. So MoreObjects.ToStringHelper is the one to be used.

It simply creates the readable formatted string given properties. It’s easy to use.

  @Override
  public String toString() {
    return MoreObjects.toStringHelper(this)
      .add("name", name)
      .add("age", age)
      .toString();
  }

It just prints like this.

User{name=Kai, age=27}