Java读写Jar-编程知识

Java读写Jar

Java提供了读写jar的类库Java.util.jar，Java获取解析jar包的工具类如下：

import java.io.File;
import java.io.IOException;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import java.util.jar.Attributes;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;
import java.util.jar.Manifest;/*** jar包解析器**/
public class JarAnalyzer {/*** jar 文件路径*/private String jarFilePath;/*** 构造函数** @param jarFilePath 文件路径*/public jarAnalyzer(String jarFilePath) {this.jarFilePath = jarFilePath;}/*** 获取jar包属性** @return jar包所有属性* @throws IOException*/public Map<String, String> getJarAttrs() throws IOException {URL url = new File(this.jarFilePath).toURI().toURL();URLClassLoader urlClassLoader = new URLClassLoader(new URL[]{url});URL manifestUrl = urlClassLoader.findResource("META-INF/MANIFEST.MF");Manifest manifest = new Manifest(manifestUrl.openStream());Attributes mainAttributes = manifest.getMainAttributes();Map<String, String> attrs = new HashMap<>();mainAttributes.forEach((key, value) -> {attrs.put(String.valueOf(key), String.valueOf(value));});return attrs;}/*** 获取入口类全路径名** @return 入口类全路径名* @throws IOException*/public String getProgamClass() throws IOException {for (String key : getJarAttrs().keySet()) {if ("program-class".equals(key)) {return getJarAttrs().get(key);}}return null;}/*** 获取jar包所有类名** @return jar包所有类名* @throws IOException*/public Set<String> getAllClasses() throws IOException {File givenFile = new File(this.jarFilePath);Set<String> classNames = new HashSet<>();try (JarFile jarFile = new JarFile(givenFile)) {Enumeration<JarEntry> e = jarFile.entries();while (e.hasMoreElements()) {JarEntry jarEntry = e.nextElement();if (jarEntry.getName().endsWith(".class")) {String className = jarEntry.getName().replace("/", ".").replace(".class", "");classNames.add(className);}}return classNames;}}}

测试类


public static void main(String[] args) throws Exception {String jarPath = "/xxx/TopSpeedWindowing.jar";JarAnalyzer jarAnalyzer = new JarAnalyzer(jarPath);log.info("jar包所有属性：");jarAnalyzer.getJarAttrs().forEach((key, value) -> {log.info("key={}，value={}", key, value);});log.info("MainClass -> {}", jarAnalyzer.getProgamClass());log.info("jar包含有的类：");jarAnalyzer.getAllClasses().forEach(clzz -> {log.info("className ->{}", clzz);});}

测试解析结果