builder 模式

public class MyTestBean {
    private long age;
    private String name;
    public MyTestBean() {
    }
    public MyTestBean(long age, String name) {
        this.age = age;
        this.name = name;
    }
    public MyTestBean(String name) {
        this.name = name;
    }
    public MyTestBean(long age) {
        this.age = age;
    }
}

public class MyTestBean {
    private long age;
    private String name;
    public long getAge() {
        return age;
    }
    public void setAge(long age) {
        this.age = age;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
}

public class MyTestBean {
    private final int id;
    private final String name;
    private final int type;
    private final float price;
    private MyTestBean(Builder builder) {
        this.id = builder.id;
        this.name = builder.name;
        this.type = builder.type;
        this.price = builder.price;
    }
    public static class Builder {
        private int id;
        private String name;
        private int type;
        private float price;
        public Builder id(int id) {
            this.id = id;
            return this;
        }
        public Builder name(String name) {
            this.name = name;
            return this;
        }
        public Builder type(int type) {
            this.type = type;
            return this;
        }
        public Builder price(float price) {
            this.price = price;
            return this;
        }
        public MyTestBean build() {
            return new MyTestBean(this);
        }
    }
}