41120634|1554|20150203|-509057.56
40998001|1554|20150203|0
40960705|1554|20150203|0
40998049|1554|20150203|0
41038826|1554|20150203|0
41081136|1554|20150203|-7198152.23
41120653|1554|20150203|-319.436349
41081091|1554|20150203|-4.28520907E+009
我决定使用如下数据结构:
Map<Integer,Map<Integer,List<Map<Integer,Float>>>
然后我的csv将被保存为:
{20150203:{1554:[{41120634:-509057.56,41120634:0,...}]}}
我的问题是如何有效地将这样的csv文件转换为我想要的数据结构?
答案 0 :(得分:3)
易于实施将是Map<K1, Map<K2, Map<K3, V>>>
之类的结构。此格式称为NestedMap
,在本例中为NestedMap3
,三个键和一个值。
使用继承实现起来非常容易,因为NestedMap3
内部使用Map<K1, NestedMap2<K2, K3, V>>
而NestedMap2
使用Map<K1, Map<K2, V>>
。
接下来,您应该考虑使用Map
的位置以及使用多个容器的位置,例如Pair<A, B>
,Triple<A, B, C>
等。
如果您的值经常更改,请使用像Pair这样的容器。如果您的值通常相同,请使用Map
。基于此,您可以混合使用某些值,例如,如果后来的值经常更改,则Map<K, Triple<A, B, C>>
可能会很好。
在您提供的方案中,第二个和第三个值通常是相同的。因此,我建议您使用NestedMap3<Integer, Integer, Integer, Float>
。
首先是设置数据结构的代码,我假设您的输入是String
中存储的inputLines
行:
NestedMap3<Integer, Integer, Integer, Float> map = new NestedMap3<>();
for (String line : inputLines) {
String[] values = inputLines.split("|");
map.put(toInt(values[0]), toInt(values[1]), toInt(values[2]), toFloat(values[3]));
}
当然,我们还需要实施toInt
和toFloat
:
public Integer toInt(final String value) {
return Integer.parseInt(value);
}
public Float toFloat(final String value) {
return Float.parseFloat(value);
}
最后实施NestedMap3
和NestedMap2
:
public class NestedMap3<K1, K2, K3, V> {
private final Map<K1, NestedMap2<K2, K3, V>> mK1ToK2ToK3V =
new HashMap<K1, NestedMap2<K2, K3, V>>();
public V put(K1 key1, K2 key2, K3 key3, V value) {
NestedMap2<K2, K3, V> k2tok3toV = mK1ToK2ToK3V.get(key1);
if (k2tok3toV == null) {
k2tok3toV = new NestedMap2<>();
mK1ToK2ToK3V.put(key1, k2tok3toV);
}
return k2tok3toV.put(key2, key3, value);
}
public V get(K1 key1, K2 key2, K3 key3) {
final NestedMap2<K2, K3, V> k2tok3toV = mK1ToK2ToK3V.get(key1);
if (k2tok3toV == null) {
return null;
} else {
return k2tok3toV.get(key2, key3);
}
}
public Map<K3, V> get(K1 key1, K2 key2) {
final NestedMap2<K2, K3, V> k2toV = mK1ToK2ToK3V.get(key1);
if (k2toV == null) {
return null;
} else {
return k2toV.get(key2);
}
}
public NestedMap2<K2, K3, V> get(K1 key1) {
return mK1ToK2ToK3V.get(key1);
}
public Set<K1> keySet() {
return mK1ToK2ToK3V.keySet();
}
public void clear() {
mK1ToK2ToK3V.clear();
}
}
public class NestedMap2<K1, K2, V> {
private final Map<K1, Map<K2, V>> mK1ToK2ToV = new HashMap<K1, Map<K2, V>>();
public V put(K1 key1, K2 key2, V value) {
Map<K2, V> k2toV = mK1ToK2ToV.get(key1);
if (k2toV == null) {
k2toV = new HashMap<>();
mK1ToK2ToV.put(key1, k2toV);
}
return k2toV.put(key2, value);
}
public V get(K1 key1, K2 key2) {
final Map<K2, V> k2toV = mK1ToK2ToV.get(key1);
if (k2toV == null) {
return null;
} else {
return k2toV.get(key2);
}
}
public Map<K2,V> get(K1 key1) {
return mK1ToK2ToV.get(key1);
}
public Set<K1> keySet() {
return mK1ToK2ToV.keySet();
}
public Iterable<Pair<K1,K2>> keys2() {
return new Iterable<Pair<K1,K2>>() {
@Override
public Iterator<Pair<K1, K2>> iterator() {
return new Iterator<Pair<K1,K2>>() {
private Iterator<Entry<K1, Map<K2, V>>> mIterator1;
private Entry<K1, Map<K2, V>> mIterator1Object;
private Iterator<K2> mIterator2;
{
mIterator1 = mK1ToK2ToV.entrySet().iterator();
if (mIterator1.hasNext()) {
mIterator1Object = mIterator1.next();
mIterator2 = mIterator1Object.getValue().keySet().iterator();
}
}
@Override
public boolean hasNext() {
if (mIterator1Object == null) {
return false;
} else {
return mIterator2.hasNext();
}
}
@Override
public Pair<K1, K2> next() {
if (mIterator1Object == null) {
throw new NoSuchElementException();
} else {
if (!mIterator2.hasNext()) {
if (!mIterator1.hasNext()) {
throw new NoSuchElementException();
} else {
mIterator1Object = mIterator1.next();
assert mIterator1Object.getValue().size() > 0 : "must contain at least one value";
mIterator2 = mIterator1Object.getValue().keySet().iterator();
}
}
return new Pair<K1, K2>(mIterator1Object.getKey(), mIterator2.next());
}
}
};
}
};
}
public Iterable<Triple<K1,K2,V>> entrySet() {
final ArrayList<Triple<K1,K2,V>> result = new ArrayList<Triple<K1,K2,V>>();
for (final Entry<K1, Map<K2, V>> entryOuter : mK1ToK2ToV.entrySet()) {
for (final Entry<K2, V> entryInner : entryOuter.getValue().entrySet()) {
result.add(new Triple<>(entryOuter.getKey(), entryInner.getKey(), entryInner.getValue()));
}
}
return result;
}
public void addAll(NestedMap2<K1, K2, V> nestedMap) {
for (final Triple<K1, K2, V> triple : nestedMap.entrySet()) {
this.put(triple.getFirst(), triple.getSecond(), triple.getThird());
}
}
public Map<K2, V> remove(K1 k1) {
return mK1ToK2ToV.remove(k1);
}
public V remove(K1 k1, K2 k2) {
final Map<K2, V> k2ToV = mK1ToK2ToV.get(k1);
if (k2ToV == null) {
return null;
} else {
return k2ToV.remove(k2);
}
}
@Override
public String toString() {
return mK1ToK2ToV.toString();
}
public void clear() {
mK1ToK2ToV.clear();
}
}
答案 1 :(得分:1)
首先,在使用CommonApache的CSV方法后,创建一个适合您数据的对象。 https://commons.apache.org/proper/commons-csv/
下面我发现了我所做的代码的摘录,我认为它对你有用。
$http({
method:'POST',
url:"http://www.example-server.com/{{param-1}}/{{param-2}}/example",
data : {
phone: $scope.phone,
company: $scope.company,
contract: '1',
privacy: '1',
email: $scope.email
},
headers: {
'Content-Type': 'application/json'
}
})