List对象去重复

不念不忘少年蓝@ 2022-12-10 03:39 197阅读 0赞

首先重写equals方法和hascode方法 里面可以自定义判断根据你需要的属性这个对象是否相同

package com.web.entity;
    
    import com.fasterxml.jackson.annotation.JsonFormat;
    import lombok.Data;
    import org.springframework.format.annotation.DateTimeFormat;
    
    import java.io.Serializable;
    import java.util.Date;
    
    
    @Data
    public class TbHuidou implements Serializable {
        private static final long serialVersionUID = 1L;
    
       
        private Integer hid;
    
       
        private String acyivity_name;
    
        private String dzh_no;
    
        
        private String cf_no;
    
       
        private String lc_no;
    
       
        private String product_code;
    
        
        private String product_type;
    
        private String function_id;
    
        private Integer sent;
        
        @DateTimeFormat(pattern="yyyy-MM-dd HH:mm:ss")
        @JsonFormat(timezone = "GMT+8",pattern = "yyyy-MM-dd HH:mm:ss")
        //@com.fasterxml.jackson.annotation.JsonIgnore
        private Date create_time;
        
        @DateTimeFormat(pattern="yyyy-MM-dd HH:mm:ss")
        @JsonFormat(timezone = "GMT+8",pattern = "yyyy-MM-dd HH:mm:ss")
        // @com.fasterxml.jackson.annotation.JsonIgnore
        private Date update_time;
    
        private Integer is_delete;
    
        public TbHuidou() {
        }
    
        /**
         * 重写eques方法
         * @param o
         * @return
         */
    
        @Override
        public boolean equals(Object o) {
            if (this == o) return true;
            if (o == null || getClass() != o.getClass()) return false;
            TbHuidou tbHuidou = (TbHuidou) o;
            return dzh_no.equals(tbHuidou.dzh_no) && lc_no.equals(tbHuidou.lc_no) && product_code.equals(tbHuidou.product_code) &&  function_id.equals(tbHuidou.function_id);
        }
    
        /**
         * 重写hascode方法
         * @return
         */
        @Override
        public int hashCode() {
            final int prime = 31;
            int result = 17;
            result = prime * result + (dzh_no == null ? 0 : dzh_no.hashCode());
            result = prime * result + (lc_no == null ? 0 : lc_no.hashCode());
            result = prime * result + (product_code == null ? 0 : product_code.hashCode());
            result = prime * result + (function_id == null ? 0 : function_id.hashCode());
            return result;
        }
    
    }

set集合去重复

List<TbHuidou> tbHuidous = tbHuidouMapper.selectHuidouByDate();
       Set<TbHuidou> ts = new HashSet<>();
       ts.addAll(tbHuidous);
       System.err.println(ts);