Java建造者模式代码示例

好的，以下是Java建造者模式的代码示例：

public class User {
    private String username;
    private String password;
    private int age;
    private String address;

    private User(UserBuilder builder) {
        this.username = builder.username;
        this.password = builder.password;
        this.age = builder.age;
        this.address = builder.address;
    }

    public String getUsername() {
        return username;
    }

    public String getPassword() {
        return password;
    }

    public int getAge() {
        return age;
    }

    public String getAddress() {
        return address;
    }

    public static class UserBuilder {
        private String username;
        private String password;
        private int age;
        private String address;

        public UserBuilder(String username, String password) {
            this.username = username;
            this.password = password;
        }

        public UserBuilder age(int age) {
            this.age = age;
            return this;
        }

        public UserBuilder address(String address) {
            this.address = address;
            return this;
        }

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

使用建造者模式创建 User 对象的示例代码如下：

User user = new User.UserBuilder("username", "password")
                .age(20)
                .address("123, Main Street")
                .build();

这样我们就可以使用链式调用来创建 User 对象，比直接在构造函数中传入参数更加灵活和易用。