1.提取List<bean>中的某属性集合； 2.List<bean>排序（需要指定升序降序和排序字段的类型）

标签：提取   list排序   

import java.lang.reflect.Field;
import java.math.BigDecimal;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;

import org.apache.commons.lang3.StringUtils;
import org.springframework.stereotype.Service;

import com.google.common.collect.Lists;

@Service
public class ListUtil {

    private static final String TRUE = "true";

    @SuppressWarnings({ "rawtypes", "unchecked" })
    public static List extractionProperty(List list, String fieldName) {

        List rList = Lists.newArrayList();

        try {
            for (int i = 0; i < list.size(); i++) {
                Object obj = list.get(i);
                Field field[] = list.get(i).getClass().getDeclaredFields();
                for (Field f : field) {
                    f.setAccessible(true);
                    if (fieldName.equals(f.getName())) {
                        rList.add(f.get(obj));
                        break;
                    }
                }
            }
            if (rList.isEmpty()) {
                return null;
            }
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }

        return rList;
    }

    @SuppressWarnings({ "rawtypes", "unchecked" })
    public static void sort(List list, String fieldName, SortType sortType, FieldType fieldType) {

        final String FIELD_NAME = fieldName;
        final int SORT_TYPE = sortType.getValue();
        final int FIELD_TYPE = fieldType.getValue();

        Collections.sort(list, new Comparator() {
            public int compare(Object arg0, Object arg1) {
                try {
                    Object object0 = (Object) arg0;
                    Object object1 = (Object) arg1;
                    Field field0[] = object0.getClass().getDeclaredFields();
                    Field field1[] = object1.getClass().getDeclaredFields();
                    String sVal0 = "";
                    String sVal1 = "";
                    BigDecimal bVal0 = BigDecimal.ZERO;
                    BigDecimal bVal1 = BigDecimal.ZERO;
                    int boVal0 = 0;
                    int boVal1 = 0;
                    for (Field f0 : field0) {
                        f0.setAccessible(true);
                        if (FIELD_NAME.equals(f0.getName())) {
                            if (FieldType.CHARACTER.getValue() == FIELD_TYPE) {
                                sVal0 = String.valueOf(f0.get(object0));
                            } else if (FieldType.DIGITAL.getValue() == FIELD_TYPE) {
                                bVal0 = new BigDecimal(String.valueOf(f0.get(object0)));
                            } else {
                                if (TRUE.equals(String.valueOf(f0.get(object0)))) {
                                    boVal0 = 1;
                                } else {
                                    boVal0 = 0;
                                }
                            }
                            break;
                        }
                    }
                    for (Field f1 : field1) {
                        f1.setAccessible(true);
                        if (FIELD_NAME.equals(f1.getName())) {
                            if (FieldType.CHARACTER.getValue() == FIELD_TYPE) {
                                sVal1 = String.valueOf(f1.get(object1));
                            } else if (FieldType.DIGITAL.getValue() == FIELD_TYPE) {
                                bVal1 = new BigDecimal(String.valueOf(f1.get(object1)));
                            } else {
                                if (TRUE.equals(String.valueOf(f1.get(object1)))) {
                                    boVal1 = 1;
                                } else {
                                    boVal1 = 0;
                                }
                            }
                            break;
                        }
                    }
                    if (SortType.DESC.getValue() == SORT_TYPE) {
                        if (FieldType.CHARACTER.getValue() == FIELD_TYPE) {
                            return sVal1.compareTo(sVal0);
                        } else if (FieldType.DIGITAL.getValue() == FIELD_TYPE) {
                            return bVal1.compareTo(bVal0);
                        } else {
                            return boVal1 < boVal0 ? 1 : -1;
                        }
                    } else {
                        if (FieldType.CHARACTER.getValue() == FIELD_TYPE) {
                            return sVal0.compareTo(sVal1);
                        } else if (FieldType.DIGITAL.getValue() == FIELD_TYPE) {
                            return bVal0.compareTo(bVal1);
                        } else {
                            return boVal0 < boVal1 ? 1 : -1;
                        }
                    }
                } catch (Exception e) {
                    e.printStackTrace();
                    return 0;
                }
            }
        });
    }
}


public enum FieldType {

    DIGITAL(0), CHARACTER(1), BOOLEAN(2);

    private int value;

    private FieldType(int value) {
        this.value = value;
    }

    public int getValue() {
        return value;
    }

    public void setValue(int value) {
        this.value = value;
    }
}


public enum SortType {

    ASC("ASC", 1), DESC("DESC", 2);

    private String name;
    private int value;

    private SortType(String name, int value) {
        this.name = name;
        this.value = value;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getValue() {
        return value;
    }

    public void setValue(int value) {
        this.value = value;
    }
}

1.提取List<bean>中的某属性集合； 2.List<bean>排序（需要指定升序降序和排序字段的类型）

标签：提取   list排序   

原文地址：http://522375.blog.51cto.com/512375/1725469