反射获取成员变量|反射获取成员变量方法构造方法反射获取成员变量方法构造方

【反射获取成员变量|反射获取成员变量方法构造方法】一个类的组成部分
1：变量
2：方法
3：构造方法
反射步骤
1：字节码文件
2：字节码对象

public class MainActivity extends AppCompatActivity {@BindView(R.id.Field_Btn) Button FieldBtn; @BindView(R.id.Method_Btn) Button MethodBtn; @BindView(R.id.Concur_Btn) Button ConcurBtn; private Class mCls; private Student mStu; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); ButterKnife.bind(this); //首先得到字节码对象 mStu = new Student(); mCls = mStu.getClass(); }@OnClick({R.id.Field_Btn, R.id.Method_Btn, R.id.Concur_Btn}) public void onViewClicked(View view) { switch (view.getId()) { case R.id.Field_Btn: getField(); setField(); break; case R.id.Method_Btn: getMethod(); break; case R.id.Concur_Btn: getConstructors(); break; } }private void getConstructors() { Constructor[] con = mCls.getDeclaredConstructors(); for (Constructor c : con) { Log.e("构造方法", c.getName()); } try { Constructor constructor = mCls.getDeclaredConstructor(String.class, String.class, int.class); Object o = constructor.newInstance("哈哈哈", "男",19); Log.e("获取构造", o.toString()); } catch (Exception e) { e.printStackTrace(); } }private void getMethod() { //得到所有成员方法 Method[] methods = mCls.getDeclaredMethods(); for (Method m : methods) { Log.e("查看方法", m.getName()); } try { Method info = mCls.getDeclaredMethod("getInfo", String.class, String.class, int.class); info.setAccessible(true); Object instance = mCls.newInstance(); info.invoke(instance, "哈哈哈哈哈", "女", 18); } catch (Exception e) { e.printStackTrace(); } }private void setField() { try { Field field = mCls.getDeclaredField("name"); field.setAccessible(true); Student instance = (Student) mCls.newInstance(); field.set(instance, "哈哈哈"); Log.e("给属性赋值", instance.toString()); } catch (Exception e) { e.printStackTrace(); } }//反射获取属性 private void getField() { //得到该类的所有成员变量 Field[] fields = mCls.getDeclaredFields(); //所有的public修饰的变量 for (Field f : fields) { Log.e("变量", "getField: " + f.getName()); } try { Field field = mCls.getDeclaredField("lick"); field.setAccessible(true); Object o = field.get(mStu); if (o instanceof String) { Log.e("通过反射获取属性的值", o.toString()); } } catch (Exception e) { e.printStackTrace(); } } }

Bean:

public class Student { private String name; private String sex; private int age; private String lick = "今天天气很好"; public Student(String name, String sex, int age) { this.name = name; this.sex = sex; this.age = age; }public Student() { }private Student(String name) { this.name = name; }public void getInfo(String name) { this.name = name; }public void getInfo(String name, String sex, int age) { Log.e("name和sex", name + ",sex=" + sex + ",age=" + age); }@Override public String toString() { return "Student{" + "name='" + name + '\'' + ", sex='" + sex + '\'' + ", age=" + age + '}'; } }