通过反射调用 getter 的最佳方法

该变数命名原则是完善的 JavaBeans规范的一部分，并得到了 爪哇咖啡豆包中类的支持。

我认为这会给你指明正确的方向:

import java.beans.*


for (PropertyDescriptor pd : Introspector.getBeanInfo(Foo.class).getPropertyDescriptors()) {
if (pd.getReadMethod() != null && !"class".equals(pd.getName()))
System.out.println(pd.getReadMethod().invoke(foo));
}

请注意，您可以自己创建 BeanInfo 或 PropertyDescriptor 实例，也就是说，不需要使用 intrspector。然而，内部检查器在内部进行一些缓存，这通常是一件好事(tm)。如果你很高兴没有缓存，你甚至可以去

// TODO check for non-existing readMethod
Object value = new PropertyDescriptor("name", Person.class).getReadMethod().invoke(person);

但是，有许多库扩展和简化了 java.beans API。Commons BeanUtils 是一个众所周知的例子。在那里，你只需要做:

Object value = PropertyUtils.getProperty(person, "name");

BeanUtils 还有其他方便的东西。即动态值转换(对象到字符串，字符串到对象) ，以简化从用户输入设置属性。

您可以为此使用 反光框架

import static org.reflections.ReflectionUtils.*;
Set<Method> getters = ReflectionUtils.getAllMethods(someClass,
withModifier(Modifier.PUBLIC), withPrefix("get"), withAnnotation(annotation));

您可以调用反射，也可以通过注释为值设置 getter 的顺序

public class Student {


private String grade;


private String name;


private String id;


private String gender;


private Method[] methods;


@Retention(RetentionPolicy.RUNTIME)
public @interface Order {
int value();
}


/**
* Sort methods as per Order Annotations
*
* @return
*/
private void sortMethods() {


methods = Student.class.getMethods();


Arrays.sort(methods, new Comparator<Method>() {
public int compare(Method o1, Method o2) {
Order or1 = o1.getAnnotation(Order.class);
Order or2 = o2.getAnnotation(Order.class);
if (or1 != null && or2 != null) {
return or1.value() - or2.value();
}
else if (or1 != null && or2 == null) {
return -1;
}
else if (or1 == null && or2 != null) {
return 1;
}
return o1.getName().compareTo(o2.getName());
}
});
}


/**
* Read Elements
*
* @return
*/
public void readElements() {
int pos = 0;
/**
* Sort Methods
*/
if (methods == null) {
sortMethods();
}
for (Method method : methods) {
String name = method.getName();
if (name.startsWith("get") && !name.equalsIgnoreCase("getClass")) {
pos++;
String value = "";
try {
value = (String) method.invoke(this);
}
catch (IllegalAccessException | IllegalArgumentException | InvocationTargetException e) {
e.printStackTrace();
}
System.out.println(name + " Pos: " + pos + " Value: " + value);
}
}
}


// /////////////////////// Getter and Setter Methods


/**
* @param grade
* @param name
* @param id
* @param gender
*/
public Student(String grade, String name, String id, String gender) {
super();
this.grade = grade;
this.name = name;
this.id = id;
this.gender = gender;
}


/**
* @return the grade
*/
@Order(value = 4)
public String getGrade() {
return grade;
}


/**
* @param grade the grade to set
*/
public void setGrade(String grade) {
this.grade = grade;
}


/**
* @return the name
*/
@Order(value = 2)
public String getName() {
return name;
}


/**
* @param name the name to set
*/
public void setName(String name) {
this.name = name;
}


/**
* @return the id
*/
@Order(value = 1)
public String getId() {
return id;
}


/**
* @param id the id to set
*/
public void setId(String id) {
this.id = id;
}


/**
* @return the gender
*/
@Order(value = 3)
public String getGender() {
return gender;
}


/**
* @param gender the gender to set
*/
public void setGender(String gender) {
this.gender = gender;
}


/**
* Main
*
* @param args
* @throws IOException
* @throws SQLException
* @throws InvocationTargetException
* @throws IllegalArgumentException
* @throws IllegalAccessException
*/
public static void main(String args[]) throws IOException, SQLException, IllegalAccessException,
IllegalArgumentException, InvocationTargetException {
Student student = new Student("A", "Anand", "001", "Male");
student.readElements();
}
}

排序后的输出

getId Pos: 1 Value: 001
getName Pos: 2 Value: Anand
getGender Pos: 3 Value: Male
getGrade Pos: 4 Value: A