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本帖最后由 865173901 于 2018-8-31 14:00 编辑
- package cn.zhangao;
-
- import java.util.ArrayList;
- import java.util.HashMap;
- import java.util.List;
- import java.util.Map;
- import java.util.Map.Entry;
-
- public class ListGroup {
-
- public static void main(String[] args) {
- List<JavaBean> list = new ArrayList<JavaBean>();
- list.add(new JavaBean("来源A", 100));
- list.add(new JavaBean("来源B", 200));
- list.add(new JavaBean("来源C", 300));
- list.add(new JavaBean("来源B", 6600));
- list.add(new JavaBean("来源A", 99800));
-
- List<JavaBean> groupList = getListByGroup(list);
- for (JavaBean bean : groupList) {
- System.out.print(bean.getGroup() + " ");
- System.out.println(bean.getMoney());
- }
- }
-
- private static List<JavaBean> getListByGroup(List<JavaBean> list) {
- List<JavaBean> result = new ArrayList<JavaBean>();
- Map<String, Integer> map = new HashMap<String, Integer>();
-
- for (JavaBean bean : list) {
- if (map.containsKey(bean.getGroup())) {
- map.put(bean.getGroup(), map.get(bean.getGroup()) + bean.getMoney());
- } else {
- map.put(bean.getGroup(), bean.getMoney());
- }
- }
- for (Entry<String, Integer> entry : map.entrySet()) {
- result.add(new JavaBean(entry.getKey(), entry.getValue()));
- }
- return result;
- }
- }
-
- class JavaBean {
- private String group;
- private int money;
-
- public JavaBean() {
- }
-
- public JavaBean(String group, int money) {
- this.group = group;
- this.money = money;
- }
-
- public String getGroup() {
- return group;
- }
-
- public void setGroup(String group) {
- this.group = group;
- }
-
- public int getMoney() {
- return money;
- }
-
- public void setMoney(int money) {
- this.money = money;
- }
-
- }
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