一种通用的toString()方法的编写，通用tostring

一种通用的toString()方法的编写，通用tostring

在ObjectAnalyzer类中编写通用的toString()方法，代码如下：

package com.corejava.reflection;

import java.lang.reflect.AccessibleObject;
import java.lang.reflect.Array;
import java.lang.reflect.Field;
import java.lang.reflect.Modifier;
import java.util.ArrayList;

public class ObjectAnalyzer {

	private ArrayList<Object> visited = new ArrayList<>();

	public String toString(Object obj) {
		if (obj == null)
			return null;
		if (visited.contains(obj))
			return "...";
		visited.add(obj);
		Class c1 = obj.getClass();
		if (c1 == String.class)
			return (String) obj;
		if (c1.isArray()) {
			String r = c1.getComponentType() + "[]{";
			for (int i = 0; i < Array.getLength(obj); i++) {
				if (i > 0)
					r += ",";
				Object val = Array.get(obj, i);
				if (c1.getComponentType().isPrimitive())
					r += val;
				else
					r += toString(val);
			}
			return r + "}";
		}
		String r = c1.getName();
		do {
			r += "[";
			Field[] fields = c1.getDeclaredFields();
			AccessibleObject.setAccessible(fields, true);
			for (Field f : fields) {
				if (!Modifier.isStatic(f.getModifiers())) {
					if (!r.endsWith("["))
						r += ",";
					r += f.getName() + "=";
					try {
						Class t = f.getType();
						Object val = f.get(obj);
						if (t.isPrimitive())
							r += val;
						else
							r += toString(val);
					} catch (Exception e) {
						e.printStackTrace();
					}
				}
			}
			r += "]";
			c1 = c1.getSuperclass();
		} while (c1 != null);
		return r;
	}
}

主函数中调用，代码如下：

package com.corejava.reflection;

import java.util.ArrayList;

public class ObjectAnalyzerTest {

	public static void main(String[] args) {
		ArrayList<Integer> squares = new ArrayList<>();
		for (int i = 1; i < 5; i++)
			squares.add(i * i);
		System.out.println(new ObjectAnalyzer().toString(squares));
	}
}

运行后打出如下：

java.util.ArrayList[elementData=class java.lang.Object[]{java.lang.Integer[value=1][][],java.lang.Integer[value=4][][],java.lang.Integer[value=9][][],java.lang.Integer[value=16][][],null,null,null,null,null,null},size=4][modCount=4][][]