如何在Java 代码中执行 JavaScript

 在实际应用中，可能会碰到这样的情况，需要在Java代码中执行JavaScript。
 例如:
  import java.io.IOException;
import java.io.PrintWriter;
import javax.faces.context.FacesContext;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class JsService {
/**
* function : 在java类中，执行javascript代码
* @param request
* @param response
*/
public static void postJavascriptOnHTML(HttpServletRequest request, HttpServletResponse response,String javascript){
StringBuffer buffer = new StringBuffer();
buffer.append("<mce:script type="text/javascript"><!--
\n").append(javascript).append("\n
// --></mce:script>\n");
outputResponse(request,response,buffer);
}
public static void alertMessageOnHTML(HttpServletRequest request, HttpServletResponse response,String message){
StringBuffer buffer = new StringBuffer();
buffer.append("<mce:script type="text/javascript"><!--
\n")
.append(" alert('" + message + "');\n")
.append("
// --></mce:script>");
outputResponse(request,response,buffer);
}
public static void putResultInResponse(HttpServletResponse response,String result){
StringBuffer buffer = new StringBuffer();
buffer.append(result);
outputResponse(null, response, buffer);
}
private static void outputResponse(HttpServletRequest request,HttpServletResponse response,StringBuffer buffer){
try {
response.setContentType("text/html;charset=UTF-8");
response.setCharacterEncoding("UTF-8");
PrintWriter writer;
writer = response.getWriter();
writer.write(buffer.toString());
writer.flush();
writer.close();
FacesContext context = FacesContext.getCurrentInstance();
if(context != null)
context.responseComplete();
} catch (IOException e) {
e.printStackTrace();
}
}
}