Java dynamic creation of injected code, injected into a class or interface and invoked through reflection

1. The class that will be injected:

/* * File name: Jnautil.java * Copyright: Sunny Technologies Co., Ltd. Copyright YYYY-YYYY, All rights reserved * Description: &lt Description > * Modified by: L.hao * Modified: 2014-11-11 * Tracking Number: < Tracking number > * Revision Number: < change tracking number > * Modified: < content > */package Co M.test;import java.util.arrays;import java.util.list;import Com.fms.xx.model.parambean;import com.sun.jna.Native;/ * * < A sentence function description > * < function Details > * * @author L.hao * @version [version number, 2014-11-11] * @see [Related class/method] * @since [Product/module Version]        This] */public class jnautil{//dll file path public String FilePath;    Public Jnautil (String filePath) {this.filepath = FilePath; } public double[] XT (list<parambean> parameterlist, double[] arr) {clibrary INSTANCE = (clibrary) native.loadlibr  ary (Filepath,clibrary.class);  int num = 0; INSTANCE. XT (Double.valueof (Parameterlist.get (num++). GetParamValue ()), Double.valueof (Parameterlist.get (num++).  GetParamValue ()), Double.valueof (Parameterlist.get (num++). GetParamValue ()), arr); Returnarr;}} 

2. The interface that will be injected

/*\ * File name:  Clibrary.java * Version    rights:  Sunny Technologies Co., Ltd. Copyright yyyy-yyyy, all  rights reserved *  Describe: < description > * Modified by:  L.hao * Modified:  2014-11-11 * Tracking Number:  < tracking number > * Revision number:  < change tracking number > * Modified content :  < Modify content > */package com.test;import com.sun.jna.library;/** * < A word function summary > * < feature details > * *  @ Author  L.hao * @version  [version number, 2014-11-11] * @see  [Related Classes/methods] * @since  [Product/module version] */public interface Clibrary extends library{public      void XT (double flj,double xtt,double flk,double arr[]);}

3, inject dynamic code and invoke

/* * File name: Writejavafile.java * Copyright: Sunny Technologies Co., Ltd. Copyright YYYY-YYYY, All rights reserved * Description : < Description > * Modified by: L.hao * Modified: 2014-11-15 * Tracking Number: < Tracking number > * Revision Number: < change tracking number > * Modified: < content > */pack Age Com.test;import java.io.bufferedreader;import Java.io.file;import java.io.filereader;import java.io.FileWriter; Import Java.io.ioexception;import Java.lang.reflect.constructor;import Java.lang.reflect.method;import Java.util.arraylist;import Java.util.arrays;import Java.util.list;import Java.util.map;import Javax.tools.diagnostic;import Javax.tools.diagnosticcollector;import Javax.tools.javafileobject;import Com.fms.xx.common.functionparam;import com.fms.xx.model.parambean;/** * Write Java File * < function description > * * @author L.hao * @ve rsion [version number, 2014-11-15] * @see [related classes/methods] * @since [Product/Module Version] */public class writejavafile{private static String Filep        Ath = "F:\\workspaces\\myeclipse10\\xxcalculate\\src\\com\\test\\clibrary.java"; Private STatic String filepath_jnautil = "F:\\workspaces\\myeclipse10\\xxcalculate\\src\\com\\test\\jnautil.java"; private static String Chfile = "f:\\soft\\apache-tomcat-7.0.52\\webapps\\xxcalculate\\upload\\141112212749\\        SharedLib.h "; /** < A word function description > * < function Details > * @param args [parameter description] * * @return void [return type description] * @throws Excepti  On * @exception throws [violation type] [violation description] * @see [Class, Class # method, Class # Member] */public static void main (string[] args) throws        Exception {//the path of the current class System.out.println ("Path of the current class:" +new File (""). GetAbsolutePath ());        Create file CreateFile (FilePath);                Read interface clibrary file String clibraryfilecontent = ReadFile (FilePath);        list<functionparam> params = Parsehfile (chfile);        The content to be spliced String appendcontent = spliceclibrarystring (params); Write the file (without stitching if it already exists) if (!clibraryfilecontent.trim (). ReplaceAll ("\\s*", ""). Contains (Appendcontent.trim ().   ReplaceAll ("\\s*", ""))) {         Writestringtofile (FilePath, clibraryfilecontent, appendcontent);                }//Read interface Jnautil file String jnautilfilecontent = ReadFile (filepath_jnautil);        Appendcontent = splicejnautilstring (params); Write the file (without stitching if it already exists) if (!jnautilfilecontent.trim (). ReplaceAll ("\\s*", ""). Contains (Appendcontent.trim (). ReplaceAll ("\\s*", "")))        {Writestringtofile (Filepath_jnautil, jnautilfilecontent, appendcontent);        } String FilePath = "F:\\workspaces\\myeclipse10\\xxcalculate\\src\\com\\test";        String SourceDir = "F:\\workspaces\\myeclipse10\\xxcalculate\\src\\com\\test";                String TargetDir = "f:\\soft\\apache-tomcat-7.0.52\\webapps\\xxcalculate\\web-inf\\classes";        Boolean result = Compiler (FilePath, SourceDir, TargetDir);        list<parambean> parames = new arraylist<parambean> (); Parambean (String Paramcode, String paramname, String paramvalue, string paramtype) paramEs.add (New Parambean ("Flj", "Air density", "0.42", "double"));        Parames.add (New Parambean ("XTT", "Air density", "0.3", "double"));        Parames.add (New Parambean ("FLK", "Air density", "0.2", "double"));        double[] arr = new DOUBLE[4];        Compile successfully, start calculation if (result) {Reflectcall (Parames,arr); }}/** * Reflection call Generated file * < function details > * @param parames * @param arr [parameter description] * @return V OID [Return type description] * @exception throws [violation type] [violation description] * @see [Class, Class # method, Class # Member] */public static void Reflectcall (list& Lt Parambean> parames, double[] arr) {try {constructor<?> conststr = Class.forName ("Co            M.test.jnautil "). Getdeclaredconstructor (New class[] {string.class});            Conststr.setaccessible (TRUE); Object bl = conststr.newinstance (new object[] {"f:\\soft\\apache-tomcat-7.0.52\\webapps\\xxcalculate\\upload\\                        141112212749\\sharedlib.dll "}); Class<?                        Extends object> clazz = Bl.getclass ();                        method = Clazz.getdeclaredmethod ("XT", List.class, Double[].class);            Method.invoke (BL, parames, arr);        System.out.println ("Calculated results:" + arrays.tostring (arr));        } catch (Exception e) {e.printstacktrace (); }}//Create a single file public static Boolean createFile (String filePath) {File File = new file (FilePath        );            if (file.exists ()) {//Determine if the file exists System.out.println ("destination file already exists" + FilePath);            File.delete ();        return false; if (Filepath.endswith (File.separator)) {//Determine if the file is a directory System.out.println ("The destination file cannot be a directory!            ");        return false; } if (!file.getparentfile (). exists ()) {//Determine if the directory where the destination file exists///If the destination file contains a folder that does not exist, create a parent folder Syst EM.OUT.PRINTLN ("The directory where the target file is not present, prepare to create it!")            "); if (!file.Getparentfile (). Mkdirs ()) {//Determine if the directory was created successfully System.out.println ("The directory where the target file was created failed!                ");            return false; }} try {if (File.createnewfile ()) {//Create destination file System.out.printl                N ("Create file succeeded:" + FilePath);            return true; } else {System.out.println ("Failed to create file!                ");            return false;            }} catch (IOException e) {//catch exception e.printstacktrace (); System.out.println ("Failed to create file!            "+ e.getmessage ());        return false; }}/** * Reads the contents of the specified file * reads the contents of the specified file into the StringBuffer * @param filePath * @return [parameter description] * * return String [Return type description] * @exception throws [violation type] [violation description] * @see [Class, Class # method, Class # Member] */public static String READF        Ile (String filePath) {File File = new file (FilePath);        BufferedReader reader = null; StringBuffer sb = NEW StringBuffer ();            try {//system.out.println ("reads the contents of the file in the behavior unit, reads a whole line at a time:");            reader = new BufferedReader (new FileReader (file));            String tempstring = null;            int line = 1; Reads one line at a time until NULL is read into the file end while ((tempstring = Reader.readline ()) = null) {Sb.append (                            tempstring). Append ("\t\n");        } reader.close ();        } catch (Exception e) {e.printstacktrace ();    } return sb.tostring ();  /** * Writes a string to the specified file * Write new content based on existing file contents * @param filePath file path * @param oldcontent already has content * @param    Newcontent New Additions * * @return void [return type description] * @exception throws [violation type] [violation description] * @see [Class, Class # method, Class # member] */ public static void Writestringtofile (String filePath, String oldcontent, String newcontent) {Stri        Ngbuffer Strbuffer = new StringBuffer (); try {Oldcontent = oldcontent.substring (0, Oldcontent.lastindexof ("}"));            Strbuffer.append (oldcontent);            Strbuffer.append (newcontent);            Strbuffer.append ("}");            Open a write file, the second parameter in the constructor true indicates that the file is written in append form FileWriter writer = new FileWriter (FilePath, false);            Writer.write (Strbuffer.tostring ());        Writer.close ();        } catch (IOException e) {e.printstacktrace (); }}/** * File compile * Call Java compiler to compile Java file * @param filePath file path * @param the directory where the SourceDir source file is located * @par      Am TargetDir Destination File directory * * @return Boolean [return type description] * @exception throws [violation type] [violation description] * @see [Class, Class # method, Class # member] */@SuppressWarnings ("Rawtypes") public static Boolean compiler (String FilePath, String SourceDir, S        Tring TargetDir) {Boolean compilerresult = false; try {diagnosticcollector<javafileobject> diagnostics = new Diagnosticcollector<javafilEobject> ();                    Compilerresult = Dynamiccompilerutil.compiler (FilePath, SourceDir, TargetDir,            Diagnostics);            if (Compilerresult) {System.out.println ("compile succeeded");                } else {System.out.println ("compilation Failed"); For (Diagnostic diagnostic:diagnostics.getDiagnostics ()) {System.out.println (diagnost                Ic.getmessage (null));        }}} catch (Exception e) {e.printstacktrace ();    } return Compilerresult; }/** * < A sentence function description > * < function Details > * @param fileName * @return [parameter description] * @return Li st<functionparam> [Return type description] * @exception throws [violation type] [violation description] * @see [Class, Class # method, Class # Member] */public static Li St<functionparam> parsehfile (String fileName) {map<string, list<functionparam>> map = Readhfile.parseh (fileName);                list<functionparam> params = (list<functionparam>) map.get ("params");    return params; }/** * Splicing interface file Contents * < function Detail Description > * @param params * @return [parameter description] * * @return String [Return class Type description] * @exception throws [violation type] [description of violation] * @see [Class, Class # method, Class # Member] */public static String spliceclibrarystring (Li        st<functionparam> params) {StringBuffer Strbuffer = new StringBuffer ();        Strbuffer.append ("public void");        Strbuffer.append (Params.get (0). Getmethodname ()). Append ("(");                    for (Functionparam functionparam:params) {strbuffer.append (Functionparam.getparamtype ())        . Append (""). Append (Functionparam.getparamname ()). Append (",");        } strbuffer.replace (Strbuffer.length ()-1, Strbuffer.length (), ""); Strbuffer.append (");").        Append ("\t\n"); return sTrbuffer.tostring (); }/** * Splicing called class contents * < function Details > * @param params * @return [parameter description] * * @return String [Return class Type description] * @exception throws [violation type] [description of violation] * @see [Class, Class # method, Class # Member] */public static String splicejnautilstring (Lis        t<functionparam> params) {String methodName = params.get (0). Getmethodname ();        StringBuffer strbuffer = new StringBuffer ();        Strbuffer.append ("public double[]");                Strbuffer.append (MethodName). Append ("(List<parambean> parameterlist, double[] arr)")        . Append ("\t\n");        Strbuffer.append ("{"). Append ("\t\n");                Strbuffer.append ("Clibrary INSTANCE = (clibrary) native.loadlibrary (Filepath,clibrary.class);")        . Append ("\t\n"); Strbuffer.append ("int num = 0;").        Append ("\t\n"); Strbuffer.append ("INSTANCE.").                Append (MethodName). Append ("(");                int count = Params.size ();        int num = 0; for (FuncTionparam functionparam:params) {num++;            if (count = = num) {continue;    } if ("Double". Equalsignorecase (Functionparam.getparamtype ())) {Strbuffer.append ("            Double.valueof (Parameterlist.get (num++). GetParamValue ()), "). Append (" \t\n ");    } if ("Char". Equalsignorecase (Functionparam.getparamtype ())) {Strbuffer.append ("            Parameterlist.get (num++). GetParamValue (). ToCharArray (), "). Append (" \t\n "); }} strbuffer.append ("arr);").        Append ("\t\n"); Strbuffer.append ("return arr;").        Append ("\t\n");        Strbuffer.append ("}"). Append ("\t\n");    return strbuffer.tostring (); }}

Java dynamic creation of injected code, injected into a class or interface and invoked through reflection