cn.yangjunda.util.AutoPackObjectUtil Maven / Gradle / Ivy

Go to download
package cn.yangjunda.util;

import javax.servlet.http.HttpServletRequest;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.math.BigDecimal;
import java.util.Enumeration;

/**
 * Created by juanda on 12/6/17.
 */
public class AutoPackObjectUtil {

    Class c;

    public static  T getObject(HttpServletRequest request, Class c) {

        T t = null;
        try {
            t = c.newInstance(); // 实例化参数对象
        } catch (InstantiationException e1) {
            e1.printStackTrace();
        } catch (IllegalAccessException e1) {
            e1.printStackTrace();
        }

        @SuppressWarnings("rawtypes")
        Enumeration e = request.getParameterNames(); // 所有请求参数

        Method[] methods = c.getDeclaredMethods(); // 参数对象的所有方法

        // 根据对象的set方法的参数类型去将请求的值做相应转换
        while (e.hasMoreElements()) {
            String paramName = e.nextElement().toString();
            String setParamName = reverseParamName(paramName); //将参数名字转换成set方法名字，如：id 转换成 setId

            for (Method method : methods) {
                if (setParamName.equals(method.getName())) {
                    try {
                        Class paramType = (method.getParameterTypes())[0]; //得到set方法参数类型
                        String value = request.getParameter(paramName);
                        adapter(t, method, paramType, value); //通过适配器将值注入进POJO里面
                    } catch (IllegalArgumentException e1) {
                        e1.printStackTrace();
                    } catch (IllegalAccessException e1) {
                        e1.printStackTrace();
                    } catch (InvocationTargetException e1) {
                        e1.printStackTrace();
                    } catch (SecurityException e1) {
                        e1.printStackTrace();
                    }
                }
            }
        }
        return t;
    }

    private static String reverseParamName(String paramName) {
        char firstChar = paramName.charAt(0);
        char toUpper = Character.toUpperCase(firstChar);
        String setParamName = "set" + String.valueOf(toUpper)
                + paramName.substring(1);
        return setParamName;
    }

    private static  void adapter(T t, Method method, Class paramType,
                                    String value) throws IllegalAccessException,
            InvocationTargetException {
        if (paramType == String.class) {
            method.invoke(t, value);
        } else if (paramType == Integer.class || paramType == int.class) {
            method.invoke(t, Integer.parseInt(value));
        } else if (paramType == Long.class || paramType == long.class) {
            method.invoke(t, Long.parseLong(value));
        } else if (paramType == Boolean.class || paramType == boolean.class) {
            method.invoke(t, Boolean.parseBoolean(value));
        } else if (paramType == Short.class || paramType == short.class) {
            method.invoke(t, Short.parseShort(value));
        } else if (paramType == Float.class || paramType == float.class) {
            method.invoke(t, Float.parseFloat(value));
        } else if (paramType == Double.class || paramType == double.class) {
            method.invoke(t, Double.parseDouble(value));
        } else if (paramType == BigDecimal.class) {
            method.invoke(t, new BigDecimal(value));
        } else if (paramType == Character.class || paramType == char.class) {
            char[] cs = value.toCharArray();
            if (cs.length > 1) {
                throw new IllegalArgumentException("参数长度太大");
            }
            method.invoke(t, value.toCharArray()[0]);
        }
    }
}