reflection

hmghaha · hmghaha · commit a1e8f94fd6ff · 2019-01-06T23:06:02.000+08:00
diff --git a/CoreJava/.classpath b/CoreJava/.classpath
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <classpath>
-	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-1.8"/>
 	<classpathentry kind="src" path="src"/>
+	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER"/>
 	<classpathentry kind="output" path="bin"/>
 </classpath>
diff --git a/CoreJava/src/v1chap05/Employee.java b/CoreJava/src/v1chap05/Employee.java
@@ -1,4 +1,4 @@
-package chap5;
+package v1chap05;
 
 import java.time.LocalDate;
 import java.util.Objects;
diff --git a/CoreJava/src/v1chap05/EmployeeTest.java b/CoreJava/src/v1chap05/EmployeeTest.java
@@ -1,4 +1,4 @@
-package chap5;
+package v1chap05;
 
 /**
  * this programe demonstrates inheritance
diff --git a/CoreJava/src/v1chap05/EnumTest.java b/CoreJava/src/v1chap05/EnumTest.java
@@ -1,4 +1,4 @@
-package chap5;
+package v1chap05;
 
 public class EnumTest {
 
diff --git a/CoreJava/src/v1chap05/Manager.java b/CoreJava/src/v1chap05/Manager.java
@@ -1,4 +1,4 @@
-package chap5;
+package v1chap05;
 
 import java.util.Objects;
 
diff --git a/CoreJava/src/v1chap05/ReflectionTest.java b/CoreJava/src/v1chap05/ReflectionTest.java
@@ -1,4 +1,4 @@
-package chap5;
+package v1chap05;
 
 import java.lang.reflect.Constructor;
 import java.lang.reflect.Field;
@@ -64,10 +64,10 @@ public static void printConstructors(Class cl) {
 			Class[] paramTypes = c.getParameterTypes();
 			for(int j = 0; j < paramTypes.length; j++) {
 				if(j > 0) 
-					System.out.print(", ");
+					System.out.print(", "); //first one "0" don't print
 				System.out.print(paramTypes[j].getName());
 			}
-			System.out.println("),");
+			System.out.println(");");
 		}
 	}
 	
diff --git a/CoreJava/src/v1chap05/objectAnalyzer/ObjectAnalyzer.java b/CoreJava/src/v1chap05/objectAnalyzer/ObjectAnalyzer.java
@@ -0,0 +1,64 @@
+package v1chap05.objectAnalyzer;
+
+import java.lang.reflect.Array;
+import java.lang.reflect.Field;
+import java.lang.reflect.Modifier;
+import java.util.ArrayList;
+import java.lang.reflect.AccessibleObject;
+
+/**
+ * Convert an object to a string represtation that lists all fields.
+ * @author Code
+ *
+ */
+
+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 cl = obj.getClass();
+		if(cl == String.class) return (String) obj;
+		if(cl.isArray()) {
+			String r = cl.getComponentType() + "[]{";
+			for(int i = 0; i < Array.getLength(obj); i++) {
+				if(i > 0) r += ",";
+				Object val = Array.get(obj, i);
+				if(cl.getComponentType().isPrimitive()) r += val;
+				else r += toString(val); //&#36882;&#24402;
+			}
+			return r + "}";
+		}
+		
+		String r =cl.getName();
+		//inspect the fields of this class and superclass
+		do {
+			r += "[";
+			Field[] fields = cl.getDeclaredFields();
+			//&#23631;&#34109;Java&#35821;&#35328;&#30340;&#35775;&#38382;&#26816;&#26597;&#65292;&#20351;&#23545;&#35937;&#30340;&#31169;&#26377;&#23646;&#24615;&#20063;&#21487;&#20197;&#34987;&#26597;&#35810;&#35774;&#32622;
+			AccessibleObject.setAccessible(fields, true); 
+			//get the names and values of all fields
+			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 += "]";
+			cl = cl.getSuperclass();
+		}
+		while(cl != null);
+		return r;
+	}
+}
diff --git a/CoreJava/src/v1chap05/objectAnalyzer/ObjectAnalyzerTest.java b/CoreJava/src/v1chap05/objectAnalyzer/ObjectAnalyzerTest.java
@@ -0,0 +1,22 @@
+package v1chap05.objectAnalyzer;
+
+import java.util.ArrayList;
+
+import com.sun.org.apache.bcel.internal.generic.NEW;
+
+/**
+ * This program use reflection to spy on objects.
+ * @author Code
+ *
+ */
+
+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));
+	}
+
+}

Original file line number	Diff line number	Diff line change
`@@ -1,4 +1,4 @@`
`1`		`-package chap5;`
	`1`	`+package v1chap05;`
`2`	`2`
`3`	`3`	`import java.time.LocalDate;`
`4`	`4`	`import java.util.Objects;`