Java相同id的数据集合，合并数据为一条，并将几个字段内容合并为一个

Java实现，当然也可以数据库实现;

/** * Created by shaozhiqi on 2019/7/31. */ public class TestUnion { @Test public void test1() { List<Map<String, Object>> dbList = new ArrayList<>(); Map map1 = new HashMap<>(); map1.put("id", "1"); map1.put("assort_no", "11111"); map1.put("name", "test"); map1.put("leve1", "high"); map1.put("leve1Desc", "高风险"); dbList.add(map1); Map map2 = new HashMap<>(); map2.put("id", "2"); map2.put("assort_no", "11111"); map2.put("name", "test"); map2.put("leve1", "low"); map2.put("leve1Desc", "低风险1"); dbList.add(map2); Map map3 = new HashMap<>(); map3.put("id", "3"); map3.put("assort_no", "11222"); map3.put("name", "test2"); map3.put("leve1", "low"); map3.put("leve1Desc", "低风险2"); dbList.add(map3); Map map4 = new HashMap<>(); map4.put("id", "4"); map4.put("assort_no", "11111"); map4.put("name", "test"); map4.put("leve1", "low"); map4.put("leve1Desc", "低风险3"); dbList.add(map4); Map map5 = new HashMap<>(); map5.put("id", "5"); map5.put("assort_no", "11111"); map5.put("name", "test"); map5.put("leve1", "high"); map5.put("leve1Desc", "高风险5"); dbList.add(map5); for (Map<String, Object> m : dbList) { List high = new ArrayList<String>(); List low = new ArrayList<String>(); for (Map<String, Object> mm : dbList) { if (mm.get("assort_no").toString().equals(m.get("assort_no").toString())) { if ("high".equals(mm.get("leve1").toString())) { high.add(mm.get("leve1Desc").toString()); } else if ("low".equals(mm.get("leve1").toString())) { low.add(mm.get("leve1Desc").toString()); } } } m.put("high", high); m.put("low", low); } dbList.forEach(m -> { System.out.println(GSON.toJson(m)); }); Map<String, Object> mapResult=new HashMap<>(); for (Map<String, Object> m : dbList) { mapResult.put(m.get("assort_no").toString(),m); } System.out.println("========================去重后=========================="); mapResult.forEach((k,v) -> { System.out.println(GSON.toJson(v)); }); } }

结果：

{"high":["高风险","高风险5"],"low":["低风险1","低风险3"],"assort_no":"11111","name":"test","leve1":"high","id":"1","leve1Desc":"高风险"} {"high":["高风险","高风险5"],"low":["低风险1","低风险3"],"assort_no":"11111","name":"test","leve1":"low","id":"2","leve1Desc":"低风险1"} {"high":[],"low":["低风险2"],"assort_no":"11222","name":"test2","leve1":"low","id":"3","leve1Desc":"低风险2"} {"high":["高风险","高风险5"],"low":["低风险1","低风险3"],"assort_no":"11111","name":"test","leve1":"low","id":"4","leve1Desc":"低风险3"} {"high":["高风险","高风险5"],"low":["低风险1","低风险3"],"assort_no":"11111","name":"test","leve1":"high","id":"5","leve1Desc":"高风险5"} ======================去重后============================ {"high":["高风险","高风险5"],"low":["低风险1","低风险3"],"assort_no":"11111","name":"test","leve1":"high","id":"5","leve1Desc":"高风险5"} {"high":[],"low":["低风险2"],"assort_no":"11222","name":"test2","leve1":"low",

 

转载于:https://www.cnblogs.com/shaozhiqi/p/11535221.html

相关资源：mmwave_studio_user_guide.pdf