List<Object>根据Object里的2个属性排序

曾经终败给现在 2022-07-15 23:15 179阅读 0赞

<pre style="font-family: 宋体; font-size: 13.5pt; background-color: rgb(255, 255, 255);"><pre name="code" class="java">import java.lang.reflect.InvocationTargetException;
    import java.lang.reflect.Method;
    import java.math.BigDecimal;
    import java.util.*;
    
    /**
     * Created by huguoju on 2016/9/22.
     * List按照指定字段排序工具类
     * @param <T> 实体对象
     */
    public class ListSortUtil<T> {
        /**
         * @param targetList 目标排序List
         * @param field1 排序字段(实体类属性名)
         * @param field2 排序字段（如果field1相同，按照field2排序）
         * @param sortMode field1排序方式（asc or  desc）
         * @param sortMode2 field2排序方式
         */
        @SuppressWarnings({ "unchecked", "rawtypes" })
        public void sort(List<T> targetList, final String field1,final String field2, final String sortMode,String sortMode2) {
            LogUtils.audit("排序前："+targetList);
            Collections.sort(targetList, new Comparator() {
                public int compare(Object arg1, Object arg2) {
                    int retVal = 0;
                    try {
                        retVal=sortObj(field1,arg1,arg2);
                        if(retVal==0){
                            if (sortMode2 != null && "desc".equals(sortMode2)){
                                retVal=sortObj(field2,arg1,arg2);
                            }else {
                                retVal=sortObj(field2,arg2,arg1);
                            }
    
                        }
                        if (sortMode != null && "desc".equals(sortMode)) {
                            // 倒序
                            retVal = -retVal;
                        }
                    } catch (Exception e) {
                        throw new RuntimeException();
                    }
                    return retVal;
                }
            });
            LogUtils.audit("排序后:"+targetList);
        }
        public int sortObj(String field,Object arg1, Object arg2) throws NoSuchMethodException,InvocationTargetException,IllegalAccessException{
            //首字母转大写
            String newStr1=field.substring(0, 1).toUpperCase()+field.replaceFirst("\\w","");
            String newStr2=field.substring(0, 1).toUpperCase()+field.replaceFirst("\\w","");
            String methodStr1="get"+newStr1;
            String methodStr2="get"+newStr2;
    
            Method method1 = ((T)arg1).getClass().getMethod(methodStr1, null);
            Method method2 = ((T)arg2).getClass().getMethod(methodStr2, null);
            Object obj1 = method1.invoke(((T)arg1), null);
            Object obj2 = method2.invoke(((T)arg2), null);
            int result=0;
            if(obj1 instanceof String) {
                // 字符串
                result = obj1.toString().compareTo(obj2.toString());
            }else if(obj1 instanceof Date) {
                // 日期
                long l = ((Date)obj1).getTime() - ((Date)obj2).getTime();
                if(l > 0) {
                    result = 1;
                }else if(l < 0) {
                    result = -1;
                }else {
                    result = 0;
                }
            }else if(obj1 instanceof Integer) {
                // 整型（Method的返回参数可以是int的，因为JDK1.5之后，Integer与int可以自动转换了）
                result = (Integer)obj1 - (Integer)obj2;
            }else if(obj1 instanceof BigDecimal){
                result=((BigDecimal) obj1).subtract((BigDecimal) obj2).intValue();
            }
            return result;
        }
    }

使用：

<pre style="font-family: 宋体; font-size: 13.5pt; background-color: rgb(255, 255, 255);">ListSortUtil<User> sortUtil=<span style="color:#000080;"><strong>new </strong></span>ListSortUtil<User>();

sortUtil.sort(list,"name","createDate","desc","asc");//name和createDate为User对象的属性

String转List<Object>

JSONArray data = JSONArray.fromObject(liststring);  
List<要转成的model> plist =  JSONArray.toList(data, 要转成的model.class);