构造方法_普通方法_成员变量的反射

package itcast.cn.Reflect;
import java.lang.reflect.Array;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.util.Arrays;
public class TestReflect {
/**
* @param args
*/
public static void main(String[] args) throws Exception {
// TODO Auto-generated method stub
String str1 = "abc";

//str1.charAt(1);
Method methodCharAt = str1.getClass().getMethod("charAt", int.class);
System.out.println(methodCharAt.invoke(str1, 1));
System.out.println(methodCharAt.invoke(str1, new Object[] {2}));
}
}

package itcast.cn.Reflect;
import java.lang.reflect.Array;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.util.Arrays;
// 使用反射将一个类中的成员变量为String类型的值中的"b"替换成"a"
public class TestReflect {
public static void main(String[] args) throws Exception {
ReflectPoint rp = new ReflectPoint(3, 5);
Field fieldY = rp.getClass().getField("y");
System.out.println(fieldY.get(rp));

Field fieldX = rp.getClass().getDeclaredField("x");
fieldX.setAccessible(true);
System.out.println(fieldX.get(rp));

System.out.println("在没有使用反射之前：" + rp.toString());
changeFieldValue(rp);
System.out.println("在没有使用反射之后：" + rp.toString());
}

private static void changeFieldValue(Object obj) throws Exception {
Field[] fields = obj.getClass().getFields();
for (int i=0; i<fields.length; i++) {
Field field = fields[i];
if (field.getType() == String.class) {
String oldValue = (String)field.get(obj);
String newValue = oldValue.replace("b", "a");
//System.out.println(changeValue);
field.set(obj, newValue);
}
}
}
}

package itcast.cn.Reflect;
public class ReflectPoint {
private int x;
public int y;
public String s1 = "bbbb";
public String s2 = "abcd";
public String s3 = "aabb";

public ReflectPoint(int x, int y) {
this.x = x;
this.y = y;
}

public String toString() {
return "s1: " + s1 + " s2: " + s2 + " s3: " + s3;
}
}