java基于反射得到对象属性值的方法

时间:2021-05-19

本文实例讲述了java基于反射得到对象属性值的方法。分享给大家供大家参考,具体如下:

通过反射机制得到对象中的属性和属性值 在对象中private没问题,在别的类中有时会报异常。下面的例子是在本对象中

/*** 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("汽车","发动机"); 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; }}

如果想调用private的属性的属性值,则要调用他的get方法了具体做法是:

把field2Value方法改为如下方式,这样在别的类中也可以得到private的属性值了

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;}

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希望本文所述对大家java程序设计有所帮助。

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