Web开发为了java端程序能删除文件，必须在.../jre/lib/security/java.policy文件中添加以下两个中的任何一段代码进去。

注：必须是服务器的本地文件，局域网内的其他机器文件根本不能访问。

一，

grant codeBase "file:/d:/-" {

permission java.io.FilePermission "D://*", "read,delete";

};

二，

//created by me

permission java.lang.RuntimePermission "createClassLoader";

permission java.io.FilePermission "D://*", "read,delete";

permission java.lang.RuntimePermission "getProtectionDomain";

例：

// Standard extensions get all permissions by default

grant codeBase "file:${{java.ext.dirs}}/*" {

permission java.security.AllPermission;

};

//一的位置

grant codeBase "file:/d:/-" {

permission java.io.FilePermission "D://*", "read,delete";

};

// default permissions granted to all domains

grant {

// Allows any thread to stop itself using the java.lang.Thread.stop()

// method that takes no argument.

// Note that this permission is granted by default only to remain

// backwards compatible.

// It is strongly recommended that you either remove this permission

// from this policy file or further restrict it to code sources

// that you specify, because Thread.stop() is potentially unsafe.

// See "http://java.sun.com/notes" for more information.

permission java.lang.RuntimePermission "stopThread";

// allows anyone to listen on un-privileged ports

permission java.net.SocketPermission "localhost:1024-", "listen";

//二的位置

permission java.lang.RuntimePermission "createClassLoader";

permission java.io.FilePermission "D://*", "read,delete";

permission java.lang.RuntimePermission "getProtectionDomain";

// "standard" properies that can be read by anyone

permission java.util.PropertyPermission "java.version", "read";

permission java.util.PropertyPermission "java.vendor", "read";

permission java.util.PropertyPermission "java.vendor.url", "read";

permission java.util.PropertyPermission "java.class.version", "read";

permission java.util.PropertyPermission "os.name", "read";

permission java.util.PropertyPermission "os.version", "read";

permission java.util.PropertyPermission "os.arch", "read";

permission java.util.PropertyPermission "file.separator", "read";

permission java.util.PropertyPermission "path.separator", "read";

permission java.util.PropertyPermission "line.separator", "read";

permission java.util.PropertyPermission "java.specification.version", "read";

permission java.util.PropertyPermission "java.specification.vendor", "read";

permission java.util.PropertyPermission "java.specification.name", "read";

permission java.util.PropertyPermission "java.vm.specification.version", "read"; permission java.util.PropertyPermission "java.vm.specification.vendor", "read"; permission java.util.PropertyPermission "java.vm.specification.name", "read"; permission java.util.PropertyPermission "java.vm.version", "read"; permission java.util.PropertyPermission "java.vm.vendor", "read"; permission java.util.PropertyPermission "java.vm.name", "read"; };