java动态调用的范例
动态调用 JAVA CLASS/JAR，不是难事。只是随便搜索了一下，没有完整的过程。於是，综合了一下，写不个综合的范例，以便提供参考。 目录结构： view plaincopy to clipboardprint?{CURDIR}\DynamicLoad.java
\{test}
\testLoad.java
{CURDIR}\DynamicLoad.java
\{test}
\testLoad.java
testLoad.java 的源码： view plaincopy to clipboardprint?
package test;
public class testLoad{
public static String testing(String name){
return "Hello, " name "! I am a public static method, I will return a String.";
}
public static void main(String []argv){
System.out.println("------------------------------Begin.");
System.out.println("Hello, dynamac load class testing!");
for(int i=0; i<argv.length; i)
System.out.println("argv[" (i) "]=" argv);
System.out.println("------------------------------End.");
}
}
package test;
public class testLoad{
public static String testing(String name){
return "Hello, " name "! I am a public static method, I will return a String.";
}
public static void main(String []argv){
System.out.println("------------------------------Begin.");
System.out.println("Hello, dynamac load class testing!");
for(int i=0; i<argv.length; i)
System.out.println("argv[" (i) "]=" argv);
System.out.println("------------------------------End.");
}
}DynamicLoad.java的源码： view plaincopy to clipboardprint?
import java.io.File;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.net.URL;
import java.net.URLClassLoader;
public class DynamicLoad extends URLClassLoader {
public static void main(String[] args) throws Exception {
dyn_load_class();
dyn_load_jar();
}
public static void dyn_load_class() {
File xFile = new File("test");//指向class所在的目录
URL xUrl;
try {
xUrl = xFile.toURL();
URLClassLoader ClassLoader = new URLClassLoader(new URL[]{xUrl});
Class cd = ClassLoader.loadClass("test.testLoad"); //class名（饱含包名)
Field[] f = cd.getDeclaredFields();
for (int k = 0; k < f.length; k) {
System.out.println(f);
}
Method mainMethod = cd.getMethod("main", new Class[]{String[].class});
String params[]={"aa","bb"};
mainMethod.invoke(null, new Object[] {params});//执行 main 方法
System.out.println("\n");
} catch (Exception e) {
e.printStackTrace();
}
}
public static void dyn_load_jar() {
DynamicLoad d = new DynamicLoad();
d.addPath("ttest.jar"); //指向 .jar 具体路径
}
public DynamicLoad() {
super(new URL, ClassLoader.getSystemClassLoader());
}
public void addPath(String paths) {
if (paths == null || paths.length() <= 0) {
return;
}
String separator = System.getProperty("path.separator");
String[] pathToAdds = paths.split(separator);
for (int i = 0; i < pathToAdds.length; i) {
if (pathToAdds != null && pathToAdds.length() > 0) {
try {
File pathToAdd = new File(pathToAdds).getCanonicalFile();
addURL(pathToAdd.toURL());
System.out.println(pathToAdd.toURL());
Class c = this.loadClass("test.testLoad"); //class名（饱含包名)
Field[] f = c.getDeclaredFields();
for (int k = 0; k < f.length; k) {
System.out.println(f);
}
Method mainMethod = c.getMethod("testing", new Class[]{String.class});
String params="小橙子";
String ret=(String)mainMethod.invoke(null, params);//执行方法
System.out.println("test.testLoad.testing() return:" ret);
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
}
import java.io.File;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.net.URL;
import java.net.URLClassLoader;
public class DynamicLoad extends URLClassLoader {
public static void main(String[] args) throws Exception {
dyn_load_class();
dyn_load_jar();
}
public static void dyn_load_class() {
File xFile = new File("test");//指向class所在的目录
URL xUrl;
try {
xUrl = xFile.toURL();
URLClassLoader ClassLoader = new URLClassLoader(new URL[]{xUrl});
Class cd = ClassLoader.loadClass("test.testLoad"); //class名（饱含包名)
Field[] f = cd.getDeclaredFields();
for (int k = 0; k < f.length; k) {
System.out.println(f);
}
Method mainMethod = cd.getMethod("main", new Class[]{String[].class});
String params[]={"aa","bb"};
mainMethod.invoke(null, new Object[] {params});//执行 main 方法
System.out.println("\n");
} catch (Exception e) {
e.printStackTrace();
}
}
public static void dyn_load_jar() {
DynamicLoad d = new DynamicLoad();
d.addPath("ttest.jar"); //指向 .jar 具体路径
}
public DynamicLoad() {
super(new URL, ClassLoader.getSystemClassLoader());
}
public void addPath(String paths) {
if (paths == null || paths.length() <= 0) {
return;
}
String separator = System.getProperty("path.separator");
String[] pathToAdds = paths.split(separator);
for (int i = 0; i < pathToAdds.length; i) {
if (pathToAdds != null && pathToAdds.length() > 0) {
try {
File pathToAdd = new File(pathToAdds).getCanonicalFile();
addURL(pathToAdd.toURL());
System.out.println(pathToAdd.toURL());
Class c = this.loadClass("test.testLoad"); //class名（饱含包名)
Field[] f = c.getDeclaredFields();
for (int k = 0; k < f.length; k) {
System.out.println(f);
}
Method mainMethod = c.getMethod("testing", new Class[]{String.class});
String params="小橙子";
String ret=(String)mainMethod.invoke(null, params);//执行方法
System.out.println("test.testLoad.testing() return:" ret);
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
}
再，还有编译方法（保存成一下.cmd文件，双击即可看到结果）： view plaincopy to clipboardprint?
@ECHO OFF
javac test\*.java
jar cvf ttest.jar ./test/*.class
javacDynamicLoad.java
java DynamicLoad
ECHO.
PAUSE
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