list中对相同name的内容，对count值加和，最终相同name合并成一条数据

痛定思痛。 2021-09-28 12:58 204阅读 0赞

package until;
    
    /**
     * Created by csucoderlee on 2019/4/30
     * <p>
     * list中对相同name的内容，对count值加和，最终相同name合并成一条数据
     */
    import java.util.ArrayList;
    import java.util.HashMap;
    import java.util.List;
    import java.util.Map;
    
    
    public class ListGroupSumList {
    
        public static void main(String[] args) {
            List<A> inList = new ArrayList<A>();
            A a1 = new A().setId(1).setName("aaaa").setCount(1);
            A a2 = new A().setId(2).setName("bbbb").setCount(4);
            A a3 = new A().setId(3).setName("cccc").setCount(3);
            A a4 = new A().setId(4).setName("aaaa").setCount(3);
            inList.add(a1);
            inList.add(a2);
            inList.add(a3);
            inList.add(a4);
    
            Map<String, A> map = new HashMap<String, A>();
            A tmpUser;
            for(A oUser : inList) {
                tmpUser = map.get(oUser.getName());
                if (tmpUser != null) {
                    tmpUser.setCount(tmpUser.getCount() + oUser.getCount());
                } else {
                    map.put(oUser.getName(), oUser);
                }
            }
    
            List<A> returnList = new ArrayList<>();
            for (A a : map.values()){
                returnList.add(a);
            }
    
            System.out.print(returnList);
        }
    
        static class A {
    
            private Integer id;
            private String name;
            private Integer count;
    
            public Integer getId() {
                return id;
            }
    
            public A setId(Integer id) {
                this.id = id;
                return this;
            }
    
            public String getName() {
                return name;
            }
    
            public A setName(String name) {
                this.name = name;
                return this;
            }
    
            public Integer getCount() {
                return count;
            }
    
            public A setCount(Integer count) {
                this.count = count;
                return this;
            }
        }
    }