Java反射根据不同方法名动态调用不同的方法(实例)
list页面的字段要求可以根据用户的喜好进行排序,所以每个用户的字段都对应着不同的顺序(字段顺序存数据库),我们从数据库里取出来的值是对象,但是前台传值是用的ajax和json array,所以就面临着一个对象到json的转换问题:1. 每个用户的字段顺序不固定,代码不能写死, 2. 根据用户字段顺序去取值,如果用if判断每个值然后调用不同的方法,if条件语句太多。然后就看了下反射。
Model 类,跟正常model一样
public class Person { private String name; private int age; private String address; private String phoneNumber; private String sex; public String getName() { return name; } // 以下是get 和set方法,省略。 }
测试类
import java.lang.reflect.InvocationTargetException; import java.lang.reflect.Method; import java.util.ArrayList; import java.util.List; public class Test { // init person object. private Person initPerson() { Person p = new Person(); p.setName("name"); p.setAge(21); p.setAddress("this is my addrss"); p.setPhoneNumber("12312312312"); p.setSex("f"); return p; } public static void main(String[] args) throws SecurityException, NoSuchMethodException, IllegalArgumentException, IllegalAccessException, InvocationTargetException { Test test = new Test(); Person p = test.initPerson(); List<String> list = new ArrayList<String>(); // Add all get method. // There is no ‘()' of methods name. list.add("getName"); list.add("getAge"); list.add("getAddress"); list.add("getPhoneNumber"); list.add("getSex"); for (String str : list) { // Get method instance. first param is method name and second param is param type. // Because Java exits the same method of different params, only method name and param type can confirm a method. Method method = p.getClass().getMethod(str, new Class[0]); // First param of invoke method is the object who calls this method. // Second param is the param. System.out.println(str + "(): Get Value is " + method.invoke(p, new Object[0])); } } }
样就可以根据数据库获取的字段遍历从对象去取相应的值了
上面那个方法是要给list添加get方法名,才能根据相应的get方法名去获取值,如果前台传过来的只是一个属性名,那我们还要转换成相应的get方法,麻烦。
public static void getValueByProperty(Person p, String propertyName) throws IntrospectionException, IllegalArgumentException, IllegalAccessException, InvocationTargetException { // get property by the argument propertyName. PropertyDescriptor pd = new PropertyDescriptor(propertyName, p.getClass()); Method method = pd.getReadMethod(); Object o = method.invoke(p); System.out.println("propertyName: " + propertyName + "\t value is: " + o); } public static void main(String[] args) throws SecurityException, NoSuchMethodException, IllegalArgumentException, IllegalAccessException, InvocationTargetException, IntrospectionException { Test test = new Test(); Person p = test.initPerson(); // get all properties. Field[] fields = p.getClass().getDeclaredFields(); for (Field field : fields) { getValueByProperty(p, field.getName()); } }
这样就能直接通过传过来的propertyName获取对应的value值了
以上这篇Java反射根据不同方法名动态调用不同的方法(实例)就是小编分享给大家的全部内容了,希望能给大家一个参考,也希望大家多多支持我们。
赞 (0)