完成jvm第一周所有作业

group24/315863321/src/main/java/jvm/loader/ClassFileLoader.java

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+package jvm.loader;
+
+
+import com.johnChnia.coding2017.basic.ArrayList;
+import com.johnChnia.coding2017.basic.List;
+
+import java.io.*;
+
+/**
+ * @// TODO: 2017/4/20 改成  try... with...resource
+ * @// TODO: 2017/4/20 close inputstream
+ * @// TODO: 2017/4/20 修改TreeInfo直接返回File
+ */
+public class ClassFileLoader {
+
+    private List<String> clzPaths = new ArrayList<String>();
+
+    public byte[] readBinaryCode(String className) {
+        for (int i = 0; i < clzPaths.size(); i++) {
+            // 找到指定类文件
+            Directory.TreeInfo treeInfo = Directory.walk(clzPaths.get(i), className);
+            if (treeInfo.files.size() > 0) {
+                try {
+                    FileInputStream fis = new FileInputStream(treeInfo.files.get(0));
+                    ByteArrayOutputStream bos = new ByteArrayOutputStream();  // 自动增长
+                    byte[] buff = new byte[1024];
+                    int len;
+                    while ((len = fis.read(buff)) != -1) {
+                        bos.write(buff, 0, len);
+                    }
+                    return bos.toByteArray();
+                } catch (Exception e) {
+                    e.printStackTrace();
+                }
+            }
+        }
+        return null;
+
+    }
+
+
+    public void addClassPath(String path) {
+        clzPaths.add(path);
+    }
+
+
+    public String getClassPath() {
+        StringBuilder sb = new StringBuilder();
+        for (int index = 0; index < clzPaths.size(); index++) {
+            sb.append(clzPaths.get(index));
+            sb.append(";");
+        }
+        return sb.toString().substring(0, sb.length() - 1);
+    }
+
+
+}

group24/315863321/src/main/java/jvm/loader/Directory.java

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+package jvm.loader;
+
+import java.io.File;
+import java.io.FilenameFilter;
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.List;
+import java.util.regex.Pattern;
+
+/**
+ * Created by john on 2017/4/17.
+ *
+ * @// TODO: 2017/4/20  实现 List.addAll(), list implements Iterable
+ */
+public final class Directory {
+
+    public static File[] local(File dir, final String regex) {
+        return dir.listFiles(new FilenameFilter() { // 文件过滤接口
+            private Pattern pattern = Pattern.compile(regex);
+
+            @Override
+            public boolean accept(File dir, String name) {
+                return pattern.matcher(new File(name).getName()).matches();
+            }
+        });
+    }
+
+    public static File[] local(String path, final String regex) {
+        return local(new File(path), regex);
+    }
+
+    public static class TreeInfo implements Iterable<File> {
+        public List<File> files = new ArrayList<>();
+        public List<File> dirs = new ArrayList<>();
+
+        @Override
+        public Iterator<File> iterator() {
+            return files.iterator();
+        }
+
+        public void addAll(TreeInfo other) {
+            files.addAll(other.files);
+            dirs.addAll(other.dirs);
+        }
+
+        @Override
+        public String toString() {
+            return "dirs: " + dirs +
+                    "\n\nfiles: " + files;
+        }
+    }
+
+    public static TreeInfo walk(String start, String regex) {
+        return recuresDirs(new File(start), regex);
+    }
+
+    public static TreeInfo walk(File start, String regex) {
+        return recuresDirs(start, regex);
+    }
+
+    public static TreeInfo walk(File start) {
+        return recuresDirs(start, ".*");// 全部
+    }
+
+    public static TreeInfo walk(String start) {
+        return recuresDirs(new File(start), ".*");// 全部
+    }
+
+    public static TreeInfo recuresDirs(File startDir, String regex) {
+        TreeInfo result = new TreeInfo();
+        for (File item : startDir.listFiles()) {
+            if (item.isDirectory()) {
+                result.dirs.add(item);
+                result.addAll(recuresDirs(item, regex));
+            } else if (item.getName().matches(regex))
+                result.files.add(item);
+        }
+        return result;
+    }
+
+}

group24/315863321/src/main/java/jvm/test/ClassFileloaderTest.java

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+package jvm.test;
+
+import jvm.loader.ClassFileLoader;
+import org.junit.After;
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Test;
+
+
+public class ClassFileloaderTest {
+
+
+    static String path1 = "/Users/john/Documents/mygit/coding2017/group24/315863321/target/classes/jvm";
+    static String path2 = "/Users/john/Documents";
+
+
+    @Before
+    public void setUp() throws Exception {
+    }
+
+    @After
+    public void tearDown() throws Exception {
+    }
+
+    @Test
+    public void testClassPath() {
+
+        ClassFileLoader loader = new ClassFileLoader();
+        loader.addClassPath(path1);
+        loader.addClassPath(path2);
+
+        String clzPath = loader.getClassPath();
+
+        Assert.assertEquals(path1 + ";" + path2, clzPath);
+
+    }
+
+    @Test
+    public void testClassFileLength() {
+
+        ClassFileLoader loader = new ClassFileLoader();
+        loader.addClassPath(path1);
+
+        String className = "EmployeeV1.class";
+
+        byte[] byteCodes = loader.readBinaryCode(className);
+
+        // 注意：这个字节数可能和你的JVM版本有关系， 你可以看看编译好的类到底有多大
+        Assert.assertEquals(1026, byteCodes.length);
+
+    }
+
+
+    @Test
+    public void testMagicNumber() {
+        ClassFileLoader loader = new ClassFileLoader();
+        loader.addClassPath(path1);
+        String className = "EmployeeV1.class";
+        byte[] byteCodes = loader.readBinaryCode(className);
+        byte[] codes = new byte[]{byteCodes[0], byteCodes[1], byteCodes[2], byteCodes[3]};
+
+
+        String acctualValue = this.byteToHexString(codes);
+
+        Assert.assertEquals("cafebabe", acctualValue);
+    }
+
+
+    private String byteToHexString(byte[] codes) {
+        StringBuffer buffer = new StringBuffer();
+        for (int i = 0; i < codes.length; i++) {
+            byte b = codes[i];
+            int value = b & 0xFF;
+            String strHex = Integer.toHexString(value);
+            if (strHex.length() < 2) {
+                strHex = "0" + strHex;
+            }
+            buffer.append(strHex);
+        }
+        return buffer.toString();
+    }
+
+}

group24/315863321/src/main/java/jvm/test/EmployeeV1.java

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+package jvm.test;
+
+public class EmployeeV1 {
+
+
+    private String name;
+    private int age;
+
+    public EmployeeV1(String name, int age) {
+        this.name = name;
+        this.age = age;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public void setAge(int age) {
+        this.age = age;
+    }
+
+    public void sayHello() {
+        System.out.println("Hello , this is class Employee ");
+    }
+
+    public static void main(String[] args) {
+        EmployeeV1 p = new EmployeeV1("Andy", 29);
+        p.sayHello();
+
+    }
+}