Map.Entry与entrySet与entry,getKey()与entry.getValue()的用法

本文主要是介绍Map.Entry与entrySet与entry,getKey()与entry.getValue()的用法，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

直接上代码 实体类

@Data
@AllArgsConstructor
@NoArgsConstructor
public class SinglePressureResultDTO {private Integer Times;   private Integer SCU_number; private Boolean Intervention;  private Long startTime_low;   private Long low_time;   private Long startTime_rise;  private Long endTime_rise;  private Long rise_time;   private Long total_time;  private Long endTime_resistance; private Long resistance_time;   private Long time_resistance_turningup;  private Float pressure_resistance_turningup;  private Float end_resistance;   private Float initial_support;private Float moving_pressure;
}

测试

public static void main(String[] args) {//给集合赋值  元素为SinglePressureResultDTO对象List<SinglePressureResultDTO> singlePressure=new ArrayList<>();singlePressure.add(new SinglePressureResultDTO(1,2,true,1l,1l,1l,1l,1l,1l,1l,1l,1l,1f,1f,1f,1f));singlePressure.add(new SinglePressureResultDTO(1,3,true,1l,1l,1l,1l,1l,1l,1l,1l,1l,1f,1f,1f,1f));        singlePressure.add(new SinglePressureResultDTO(1,4,true,2l,1l,1l,1l,1l,1l,1l,1l,1l,1f,1f,1f,1f));singlePressure.add(new SinglePressureResultDTO(1,4,false,3l,1l,1l,1l,1l,1l,1l,1l,1l,1f,1f,1f,1f));System.out.println(adapterToASQTotalDTO(singlePressure)+"   )))");public static ASQTotalDTO adapterToASQTotalDTO(List<SinglePressureResultDTO> singlePressure) {ASQTotalDTO asqTotalDTO = new ASQTotalDTO();List<ASQSingleDTO> asqs = new ArrayList<>();if (CollectionUtil.isEmpty(singlePressure)) {return asqTotalDTO;}//将传递过来的集合以SCU_number属性进行分组  类似于key-value的形式  //key是SCU_number,value是SCU_number符合条件的所有对象(集合)//{2=[SinglePressureResultDTO(Times=1, SCU_number=2, Intervention=true, startTime_low=1, low_time=1, startTime_rise=1, endTime_rise=1, rise_time=1, total_time=1, endTime_resistance=1, resistance_time=1, time_resistance_turningup=1, pressure_resistance_turningup=1.0, end_resistance=1.0, initial_support=1.0, moving_pressure=1.0)],// 3=[SinglePressureResultDTO(Times=1, SCU_number=3, Intervention=true, startTime_low=1, low_time=1, startTime_rise=1, endTime_rise=1, rise_time=1, total_time=1, endTime_resistance=1, resistance_time=1, time_resistance_turningup=1, pressure_resistance_turningup=1.0, end_resistance=1.0, initial_support=1.0, moving_pressure=1.0)],// 4=[SinglePressureResultDTO(Times=1, SCU_number=4, Intervention=true, startTime_low=2, low_time=1, startTime_rise=1, endTime_rise=1, rise_time=1, total_time=1, endTime_resistance=1, resistance_time=1, time_resistance_turningup=1, pressure_resistance_turningup=1.0, end_resistance=1.0, initial_support=1.0, moving_pressure=1.0), SinglePressureResultDTO(Times=1, SCU_number=4, Intervention=false, startTime_low=3, low_time=1, startTime_rise=1, endTime_rise=1, rise_time=1, total_time=1, endTime_resistance=1, resistance_time=1, time_resistance_turningup=1, pressure_resistance_turningup=1.0, end_resistance=1.0, initial_support=1.0, moving_pressure=1.0)]}    Map<Integer, List<SinglePressureResultDTO>> scuResult = singlePressure.stream().collect(Collectors.groupingBy(SinglePressureResultDTO::getSCU_number));System.out.println(scuResult+"  scuResult");//获取每一个集合中的元素  确切来说，获取每一个key-value//并且遍历每一个key-valuefor (Map.Entry<Integer, List<SinglePressureResultDTO>> entry : scuResult.entrySet()) {//在这里可以打印每一个key-valueSystem.out.println(entry+"  key-value");ASQSingleDTO asqSingle = new ASQSingleDTO();List<ASQCirculateDTO> auto = new ArrayList<>();List<ASQCirculateDTO> manual = new ArrayList<>();//遍历每一个key-value中的value(注意 value是集合)for (SinglePressureResultDTO pressure : entry.getValue()) {//同样可以获取到entry中的key以及entry中的valueSystem.out.println(entry.getKey()+"  **&^&%^");System.out.println(entry.getValue()+"   *&^%");ASQCirculateDTO dto = new ASQCirculateDTO();dto.setDownStartTime(pressure.getStartTime_low());dto.setDownEndTime(pressure.getStartTime_rise());dto.setUpStartTime(pressure.getStartTime_rise());dto.setUpEndTime(pressure.getEndTime_rise());dto.setEndStrength(pressure.getEnd_resistance());dto.setInflectionPressure(pressure.getPressure_resistance_turningup());dto.setInitStrength(pressure.getInitial_support());if (pressure.getIntervention()) {manual.add(dto);} else {auto.add(dto);}}asqSingle.setScuNo(entry.getKey());System.out.println(entry.getKey()+"   entry.getKey()");asqSingle.setAsqNum(auto.size());asqSingle.setNsqNum(manual.size());asqSingle.setAuto(auto);asqSingle.setManual(manual);//每个支架数据作为asqs的一个元素asqs.add(asqSingle);}asqTotalDTO.setAsqs(asqs);System.out.println(asqTotalDTO);List<ASQSingleDTO> asqs1 = asqTotalDTO.getAsqs();//for (ASQSingleDTO asqSingleDTO:asqs1) {//System.out.println(asqSingleDTO+"   -----");//}System.out.println(asqs1+" asq1");return asqTotalDTO;}}

运行 System.out.println(asqs1+" asq1");结果

[ASQSingleDTO{scuNo=2, asqNum=0, nsqNum=1, auto=[], manual=[ASQCirculateDTO{downStartTime=1, downEndTime=1, moveStartTime=null, moveEndTime=null, upStartTime=1, upEndTime=1, inflectionPressure=1.0, initStrength=1.0, endStrength=1.0}]}, 
ASQSingleDTO{scuNo=3, asqNum=0, nsqNum=1, auto=[], manual=[ASQCirculateDTO{downStartTime=1, downEndTime=1, moveStartTime=null, moveEndTime=null, upStartTime=1, upEndTime=1, inflectionPressure=1.0, initStrength=1.0, endStrength=1.0}]}, 
ASQSingleDTO{scuNo=4, asqNum=1, nsqNum=1, auto=[ASQCirculateDTO{downStartTime=3, downEndTime=1, moveStartTime=null, moveEndTime=null, upStartTime=1, upEndTime=1, inflectionPressure=1.0, initStrength=1.0, endStrength=1.0}], manual=[ASQCirculateDTO{downStartTime=2, downEndTime=1, moveStartTime=null, moveEndTime=null, upStartTime=1, upEndTime=1, inflectionPressure=1.0, initStrength=1.0, endStrength=1.0}]}] asq1

打印key-value运行结果

2=[SinglePressureResultDTO(Times=1, SCU_number=2, Intervention=true, startTime_low=1, low_time=1, startTime_rise=1, endTime_rise=1, rise_time=1, total_time=1, endTime_resistance=1, resistance_time=1, time_resistance_turningup=1, pressure_resistance_turningup=1.0, end_resistance=1.0, initial_support=1.0, moving_pressure=1.0)]  key-value
3=[SinglePressureResultDTO(Times=1, SCU_number=3, Intervention=true, startTime_low=1, low_time=1, startTime_rise=1, endTime_rise=1, rise_time=1, total_time=1, endTime_resistance=1, resistance_time=1, time_resistance_turningup=1, pressure_resistance_turningup=1.0, end_resistance=1.0, initial_support=1.0, moving_pressure=1.0)]  key-value
4=[SinglePressureResultDTO(Times=1, SCU_number=4, Intervention=true, startTime_low=2, low_time=1, startTime_rise=1, endTime_rise=1, rise_time=1, total_time=1, endTime_resistance=1, resistance_time=1, time_resistance_turningup=1, pressure_resistance_turningup=1.0, end_resistance=1.0, initial_support=1.0, moving_pressure=1.0), SinglePressureResultDTO(Times=1, SCU_number=4, Intervention=false, startTime_low=3, low_time=1, startTime_rise=1, endTime_rise=1, rise_time=1, total_time=1, endTime_resistance=1, resistance_time=1, time_resistance_turningup=1, pressure_resistance_turningup=1.0, end_resistance=1.0, initial_support=1.0, moving_pressure=1.0)]  key-value

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