package com.coderising.jvm.test;
import org.junit.After;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;
import com.coderising.jvm.loader.ClassFileLoader;
import java.io.FileNotFoundException;
public class ClassFileloaderTest {
static String path1 = "C:\\Users\\liuxin\\git\\coding2017\\liuxin\\mini-jvm\\bin";
static String path2 = "C:\temp";
@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() throws FileNotFoundException {
ClassFileLoader loader = new ClassFileLoader();
loader.addClassPath(ClassFileloaderTest.class.getResource("/").getPath());
String className = "com.coderising.jvm.test.EmployeeV1";
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(1056, byteCodes.length);
}
@Test
public void testMagicNumber() throws FileNotFoundException {
ClassFileLoader loader = new ClassFileLoader();
loader.addClassPath(ClassFileloaderTest.class.getResource("/").getPath());
String className = "com.coderising.jvm.test.EmployeeV1";
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();
}
}