list頁(yè)面的字段要求可以根據(jù)用戶的喜好進(jìn)行排序，所以每個(gè)用戶的字段都對(duì)應(yīng)著不同的順序（字段順序存數(shù)據(jù)庫(kù)），我們從數(shù)據(jù)庫(kù)里取出來(lái)的值是對(duì)象，但是前臺(tái)傳值是用的ajax和json array，所以就面臨著一個(gè)對(duì)象到j(luò)son的轉(zhuǎn)換問(wèn)題：1. 每個(gè)用戶的字段順序不固定，代碼不能寫死， 2. 根據(jù)用戶字段順序去取值，如果用if判斷每個(gè)值然后調(diào)用不同的方法，if條件語(yǔ)句太多。然后就看了下反射。
Model 類，跟正常model一樣
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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。} |
測(cè)試類
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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])); } }} |
樣就可以根據(jù)數(shù)據(jù)庫(kù)獲取的字段遍歷從對(duì)象去取相應(yīng)的值了
上面那個(gè)方法是要給list添加get方法名，才能根據(jù)相應(yīng)的get方法名去獲取值，如果前臺(tái)傳過(guò)來(lái)的只是一個(gè)屬性名，那我們還要轉(zhuǎn)換成相應(yīng)的get方法，麻煩。
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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()); } } |
這樣就能直接通過(guò)傳過(guò)來(lái)的propertyName獲取對(duì)應(yīng)的value值了
以上這篇Java反射根據(jù)不同方法名動(dòng)態(tài)調(diào)用不同的方法(實(shí)例)就是小編分享給大家的全部?jī)?nèi)容了，希望能給大家一個(gè)參考，也希望大家多多支持服務(wù)器之家。
