Java 8 的 java.util.function.* POJO 的反射新方法

酒云 • 2018年04月12日 • 阅读:1913 • java

上代码,看例子

写一个普通的 POJO

public class City {

    private String name;
    private String code;

    public City() {
    }

    public City(String name, String code) {
        this.name = name;
        this.code = code;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getCode() {
        return code;
    }

    public void setCode(String code) {
        this.code = code;
    }

}

传统的方式

// Use a constructor with parameters to create a City
City sf = new City("San Francisco", "SF");
// Use a default constructor with no parameters to create a City
City la = new City();
// Set the members using setters
la.setName("Los Angeles");
la.setCode("LA");

新的 getter 访问方式

// Use the City's method references and assign them to functions
Function<City, String> getNameFunction = City::getName;
Function<City, String> getCodeFunction = City::getCode;

System.out.println("The code for "

        + getNameFunction.apply(sf)
        + " is "
        + getCodeFunction.apply(sf));

-> The code for San Francisco is SF

新的 setter 访问方式

// Use the City's method references and assign them to biconsumers
BiConsumer<City, String> setNameBiConsumer = City::setName;
BiConsumer<City, String> setCodeBiConsumer = City::setCode;
City ny = new City();
setNameBiConsumer.accept(ny, "New York");
setCodeBiConsumer.accept(ny, "NY");

访问 constructor 创建新实例

// Use the City's constructor method reference to create
// a default constructor reference.
Supplier<City> defaultConstructor = City::new;

City sd = defaultConstructor.get();
sd.setName("San Diego");
sd.setCode("SD");

带参数的构建器

// Use the City's constructor method reference to create
// a two-parameter constructor reference.
BiFunction<String, String, City> twoParameterConstructor = City::new;

City dc = twoParameterConstructor.apply("Washington, D. C.", "DC");

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