本文實(shí)例講述了java基于反射得到對(duì)象屬性值的方法。分享給大家供大家參考,具體如下:
通過(guò)反射機(jī)制得到對(duì)象中的屬性和屬性值 在對(duì)象中private沒(méi)問(wèn)題,在別的類中有時(shí)會(huì)報(bào)異常。下面的例子是在本對(duì)象中
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/** * Engine entity. @author MyEclipse Persistence Tools */ public class Engine implements java.io.Serializable { // Fields private Long engineId; private String engineName; private String engineType; // Constructors /** default constructor */ public Engine() { } /** minimal constructor */ public Engine(Long engineId) { this .engineId = engineId; } public Engine(String engineName, String engineType) { this .engineName = engineName; this .engineType = engineType; } /** full constructor */ public Engine(Long engineId, String engineName, String engineType) { this .engineId = engineId; this .engineName = engineName; this .engineType = engineType; } // Property accessors public Long getEngineId() { return this .engineId; } public void setEngineId(Long engineId) { this .engineId = engineId; } public String getEngineName() { return this .engineName; } public void setEngineName(String engineName) { this .engineName = engineName; } public String getEngineType() { return this .engineType; } public void setEngineType(String engineType) { this .engineType = engineType; } public static void main(String[] args) throws Exception { Engine m = new Engine( "汽車" , "發(fā)動(dòng)機(jī)" ); Class clazz = m.getClass(); Field[] f = clazz.getDeclaredFields(); String[] name = field2Name(f); Object[] value = field2Value(f, m); showNameAndValue(name, value); } public static void showNameAndValue(String[] name, Object[] value) { for ( int i = 0 ; i < name.length; i++) { System.out.println( "--" + i + "--" ); System.out.println( "name:" + name[i]); System.out.println( "Value:" + value[i]); System.out.println( "-- --" ); } } public static String[] field2Name(Field[] f) { String[] name = new String[f.length]; for ( int i = 0 ; i < f.length; i++) { name[i] = f[i].getName(); } return name; } public static Object[] field2Value(Field[] f, Object o) throws Exception { Object[] value = new Object[f.length]; for ( int i = 0 ; i < f.length; i++) { value[i] = f[i].get(o); } return value; } } |
如果想調(diào)用private的屬性的屬性值,則要調(diào)用他的get方法了具體做法是:
把field2Value方法改為如下方式,這樣在別的類中也可以得到private的屬性值了
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public static Object[] field2Value(Field[] fields, Object o) throws Exception { Object[] values = new Object[fields.length]; Class classType = o.getClass(); for ( int i = 0 ; i < fields.length; i++) { String fieldName = fields[i].getName(); String firstLetter = fieldName.substring( 0 , 1 ).toUpperCase(); String getMethodName = "get" + firstLetter + fieldName.substring( 1 ); Method getMethod = classType.getMethod(getMethodName, new Class[] {}); values[i] = getMethod.invoke(o, new Object[] {}); } return values; } |
希望本文所述對(duì)大家java程序設(shè)計(jì)有所幫助。