构建者（Builder）模式

   public class Person {
            private final String mName;
            private final int mAge;
            private final int mGender;
            private final String mAddre;

            private Person(Builder builder) {
                mName = builder.mName;
                mAge = builder.mAge;
                mGender = builder.mGender;
                mAddre = builder.mAddre;
            }

            public int getmAge() {
                return mAge;
            }

            public int getmGender() {
                return mGender;
            }

            public String getmName() {
                return mName;
            }

            public String getmAddre() {
                return mAddre;
            }

            public static final class Builder {
                private String mName;
                private int mAge;
                private int mGender;
                private String mAddre;

                public Builder(String name, int age, 
                int gender) {
                    mName = name;
                    mAge = age;
                    mGender = gender;
                }

                public Builder mAddre(String val) {
                    mAddre = val;
                    return this;
                }

                public Person build() {
                    return new Person(this);
                }
            }
        }