检测JAR包JDK编译版本是否1.5

所在项目的jdk版本是jdk1.5,而开源框架很多都升级到了1.6的版本，为了测试开源框架与现有jdk的兼容性，分享代码如下:

   
package org.myframework.jdbc;
import java.io.BufferedReader;
import java.io.DataInputStream;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.zip.ZipEntry;
import java.util.zip.ZipFile;
import java.util.zip.ZipInputStream;
//The first 4 bytes are a magic number, 0xCAFEBABe, to identify a valid class file then the next 2 bytes identify the class format version (major and minor). 
//Possible major/minor value : 
//create table m2_lib ( library1 varchar2(100)) ;
//select '"'||replace(library1,'\','/')||'",' from m2_lib   ;
//
//select * from    m2_lib  for update;
//major  minor Java platform version 
//45       3           1.0
//45       3           1.1
//46       0           1.2
//47       0           1.3
//48       0           1.4
//49       0           1.5
//50       0           1.6
public class ClassVersionChecker {
 public static void main(String[] args) throws IOException {
  // for (int i = 0; i < args.length; i++)
  // checkClassVersion(args[i]);
  String[] jarsStrings = {
         "C:/Users/wanghui/.m2/repository/net/sf/ehcache/ehcache-core/2.4.8/ehcache-core-2.4.8.jar" 
 };
  for (int i = 0; i < jarsStrings.length; i++)
   scanJarFileJDK1_5_Version(jarsStrings[i]);
 }
 private static void checkClassVersion(String filename) throws IOException {
  DataInputStream in = new DataInputStream(new FileInputStream(filename));
  int magic = in.readInt();
  if (magic != 0xcafebabe) {
   System.out.println(filename + " is not a valid class!");
   ;
  }
  int minor = in.readUnsignedShort();
  int major = in.readUnsignedShort();
  System.out.println(filename + ": " + major + " . " + minor);
  in.close();
 }
 private static void checkClassVersion(InputStream in1) throws IOException {
  DataInputStream in = new DataInputStream(in1);
  int magic = in.readInt();
  if (magic != 0xcafebabe) {
   System.out.println(in + " is not a valid class!");
   ;
  }
  int minor = in.readUnsignedShort();
  int major = in.readUnsignedShort();
  
  System.out.println(": " + major + " . " + minor);
  in.close();
 }
 
 private static void checkClassJDK1_5_Version(String jar,InputStream in1) throws IOException {
  DataInputStream in = new DataInputStream(in1);
  int magic = in.readInt();
  if (magic != 0xcafebabe) {
   System.out.println(in + " is not a valid class!");
   ;
  }
  int minor = in.readUnsignedShort();
  int major = in.readUnsignedShort();
  if (major >49)
  System.out.println(jar+": " + major + " . " + minor);
  in.close();
 }
 
 
 public static void scanJarFileJDK1_5_Version(String zipname) {
  try {
   ZipInputStream zin = new ZipInputStream(
     new FileInputStream(zipname));
   ZipEntry entry;
   while ((entry = zin.getNextEntry()) != null) {
    if (entry.getName().endsWith(".class")) {
     ZipFile file = new ZipFile(zipname);
     InputStream in = file.getInputStream(entry);
     checkClassJDK1_5_Version(zipname,in);
     break;
    }
   }
   zin.close();
  } catch (IOException e) {
  }
 }
 
 public static void scanZipFile(String zipname) {
  try {
   ZipInputStream zin = new ZipInputStream(
     new FileInputStream(zipname));
   ZipEntry entry;
   while ((entry = zin.getNextEntry()) != null) {
    System.out.println(entry.getName());
    zin.closeEntry();
   }
   zin.close();
  } catch (IOException e) {
  }
 }
 public static void scanClassFile(String zipname) {
  try {
   ZipInputStream zin = new ZipInputStream(
     new FileInputStream(zipname));
   ZipEntry entry;
   while ((entry = zin.getNextEntry()) != null) {
    if (entry.getName().endsWith(".class")) {
     System.out.println(entry.getName());
     ZipFile file = new ZipFile(zipname);
     InputStream in = file.getInputStream(entry);
     System.out.println(in);
     checkClassVersion(in);
     break;
    }
   }
   zin.close();
  } catch (IOException e) {
  }
 }
 public static void loadZipFile(String zipname, String name) {
  try {
   ZipInputStream zin = new ZipInputStream(
     new FileInputStream(zipname));
   ZipEntry entry;
   System.out.println("");
   while ((entry = zin.getNextEntry()) != null) {
    if (entry.getName().equals(name)) {
     BufferedReader in = new BufferedReader(
       new InputStreamReader(zin));
     String s;
     while ((s = in.readLine()) != null)
      System.out.println(s + "/n");
    }
    zin.closeEntry();
   }
   zin.close();
  } catch (IOException e) {
  }
 }
}
 

评论

1 楼 leo569 2016-08-04  

很少评论。但楼主分享出的就是我需要的！32个赞！
Unsupported major.minor version 51.0 这类错误很难定位错误位置！只好大量查jar包。如果有朋友有办法定位错误，请告知。非常感谢