Java中，对List存放的对象按指定属性排序_JAVA_编程开发_程序员俱乐部

class="java" name="code">
    /**
     * 对List对象按照某个成员变量进行排序
     * @param list       List对象
     * @param sortField  排序的属性名称
     * @param sortMode   排序方式：ASC，DESC 任选其一
     */
    public static <T> void sortList(List<T> list, final String sortField, final String sortMode) {
        Collections.sort(list, new Comparator<T>() {
            @Override
            public int compare(T o1, T o2) {
                try {
                    Class clazz = o1.getClass();
                    Field field = clazz.getDeclaredField(sortField); //获取成员变量
                    field.setAccessible(true); //设置成可访问状态
                    String typeName = field.getType().getName().toLowerCase(); //转换成小写

                    Object v1 = field.get(o1); //获取field的值
                    Object v2 = field.get(o2); //获取field的值

                    boolean ASC_order = (sortMode == null || "ASC".equalsIgnoreCase(sortMode));

                    //判断字段数据类型，并比较大小
                    if(typeName.endsWith("string")) {
                        String value1 = v1.toString();
                        String value2 = v2.toString();
                        return ASC_order ? value1.compareTo(value2) : value2.compareTo(value1);
                    }
                    else if(typeName.endsWith("short")) {
                        Short value1 = Short.parseShort(v1.toString());
                        Short value2 = Short.parseShort(v2.toString());
                        return ASC_order ? value1.compareTo(value2) : value2.compareTo(value1);
                    }
                    else if(typeName.endsWith("byte")) {
                        Byte value1 = Byte.parseByte(v1.toString());
                        Byte value2 = Byte.parseByte(v2.toString());
                        return ASC_order ? value1.compareTo(value2) : value2.compareTo(value1);
                    }
                    else if(typeName.endsWith("char")) {
                        Integer value1 = (int)(v1.toString().charAt(0));
                        Integer value2 = (int)(v2.toString().charAt(0));
                        return ASC_order ? value1.compareTo(value2) : value2.compareTo(value1);
                    }
                    else if(typeName.endsWith("int") || typeName.endsWith("integer")) {
                        Integer value1 = Integer.parseInt(v1.toString());
                        Integer value2 = Integer.parseInt(v2.toString());
                        return ASC_order ? value1.compareTo(value2) : value2.compareTo(value1);
                    }
                    else if(typeName.endsWith("long")) {
                        Long value1 = Long.parseLong(v1.toString());
                        Long value2 = Long.parseLong(v2.toString());
                        return ASC_order ? value1.compareTo(value2) : value2.compareTo(value1);
                    }
                    else if(typeName.endsWith("float")) {
                        Float value1 = Float.parseFloat(v1.toString());
                        Float value2 = Float.parseFloat(v2.toString());
                        return ASC_order ? value1.compareTo(value2) : value2.compareTo(value1);
                    }
                    else if(typeName.endsWith("double")) {
                        Double value1 = Double.parseDouble(v1.toString());
                        Double value2 = Double.parseDouble(v2.toString());
                        return ASC_order ? value1.compareTo(value2) : value2.compareTo(value1);
                    }
                    else if(typeName.endsWith("boolean")) {
                        Boolean value1 = Boolean.parseBoolean(v1.toString());
                        Boolean value2 = Boolean.parseBoolean(v2.toString());
                        return ASC_order ? value1.compareTo(value2) : value2.compareTo(value1);
                    }
                    else if(typeName.endsWith("date")) {
                        Date value1 = (Date)(v1);
                        Date value2 = (Date)(v2);
                        return ASC_order ? value1.compareTo(value2) : value2.compareTo(value1);
                    }
                    else if(typeName.endsWith("timestamp")) {
                        Timestamp value1 = (Timestamp)(v1);
                        Timestamp value2 = (Timestamp)(v2);
                        return ASC_order ? value1.compareTo(value2) : value2.compareTo(value1);
                    }
                    else {
                        //调用对象的compareTo()方法比较大小
                        Method method = field.getType().getDeclaredMethod("compareTo", new Class[]{field.getType()});
                        method.setAccessible(true); //设置可访问权限
                        int result  = (Integer)method.invoke(v1, new Object[]{v2});
                        return ASC_order ? result : result*(-1);
                    }
                }
                catch (Exception e) {
                    String err = e.getLocalizedMessage();
                    System.out.println(err);
                    e.printStackTrace();
                }
                return 0; //未知类型，无法比较大小
            }
        });
    }