利用invoke方法自动绑定JavaBean

最新推荐文章于 2023-12-12 08:15:00 发布

最新推荐文章于 2023-12-12 08:15:00 发布 · 135 阅读

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本文介绍了一种通过反射机制实现的Java Bean绑定方法，该方法可以从HTTP请求中获取参数，并将其绑定到Java Bean实例的相应属性上。同时，文章提供了一个示例性的类`BeanBind`，展示了如何根据不同类型（如String、Integer等）的数据进行适当的转换和赋值。

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mport java.lang.reflect.Method;
import java.util.Date;

import javax.servlet.http.HttpServletRequest;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

public class BeanBind {

    public static Log log = LogFactory.getLog(BeanBind.class);
    // choose the appropriate method to invoke and set the class properity

    public static Method select(Method[] method, String name, Class clz) {
        Method methods=null;
        for (int i = 0; i < method.length; i++) {
            int a = method[i].getName().length();
            if (method[i].getName().substring(3, a).equalsIgnoreCase(name)
                    && (method[i].getName().startsWith("set"))) {
                log.info("get the appropriate method: "+clz.getClass()+"."+method[i].getName());

                return method[i];

            }

        }
        System.out.println("check");
        return null;

    }
    //get the data from request and bind into Class clz
    public static Object bind(Class clz,HttpServletRequest request) throws InstantiationException,
            IllegalAccessException {

        java.lang.reflect.Field[] field = clz.getDeclaredFields();
        Method[] method = clz.getDeclaredMethods();
        Object obj = clz.newInstance();
        System.out.println("field.length: "+field.length);

        for (int i = 0; i < field.length; i++) {

            String parser = null;
            Method meod = null;
            String type = field[i].getType().getSimpleName();
            String str = field[i].getName();
            parser=request.getParameter(str);
            meod = select(method, str, clz);
            log.info("method: "+meod.getName()+ " bind the properity: "+str+" value : "+parser);

            if (type.equalsIgnoreCase("String")) {


                try {
                    Object[] arg = { parser };
                    System.out.println("String");
                    meod.invoke(obj, arg);


                } catch (Exception e) {
                    log.error("String value: "+parser+ "invoke error: "+clz.getName());

                }

            } else if (type.equalsIgnoreCase("Integer")) {


                try {
                   Object[] arg = { Integer.valueOf(parser) };
                    meod.invoke(obj, arg);

                } catch (Exception e) {
                    log.error("Integer value: "+parser+ "invoke error: "+clz.getName());
                }

            } else if (type.equalsIgnoreCase("Double")) {



                try {

                    Object[] arg = { Double.valueOf(parser) };
                    meod.invoke(obj, arg);


                } catch (Exception e) {
                    log.error("Double value: "+parser+ "invoke error: "+clz.getName());
                }

            } else if (type.equalsIgnoreCase("Float")) {



                try {
                    Object[] arg = { Float.valueOf(parser) };
                    meod.invoke(obj, arg);


                } catch (Exception e) {
                    log.error("Float value: "+parser+ "invoke error: "+clz.getName());
                }

            } else if (type.equalsIgnoreCase("date")) {


                try {
                    Date date = new Date(parser);
                    Object[] arg ={ date };
                    meod.invoke(obj, arg);

                } catch (Exception e) {
                    log.error("Date value: "+parser+ "invoke error: "+clz.getName());

                }

            }
            System.out.println("ahaha");

        }
        return obj;

    }

}
具体的调用方法如下.相应的值是从HttpRequest (Form表单)获取关于验证方法可以在JavaBean中自己定义一个validator方法.然后动态调用
User user=new User();
   Class clzs=user.getClass();
user=(User) BeanBind.bind(clzs, request);