java 读取文本文件并将键值对存储在不同的映射中
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Read the text file and store the key-value pairs in different maps
提问by SASM
This is the text file:
这是文本文件：
#Person
PRIM_KEY=personId
SEX=gender
YEARS=age
NAME=fullName
#Automobil
PRIM_KEY=registrationNumber
MAKE=manufacturer
TYPE=model
Read the file:
读取文件：
Scanner scanner = new Scanner(new FileReader("C:/workspace/column-mapping.txt"));
When I encounter #Person, in the following map defined:
当我遇到#Person，在下面的地图中定义：
Map<String, String> personMap = new LinkedHashMap<String, String>();
I want to store the key-value pairs below it.
So store these key-value pairs in personMap:
我想在它下面存储键值对。因此，将这些键值对存储在personMap：
PRIM_KEY=personId
SEX=gender
YEARS=age
NAME=fullName
Similarly when I encounter #Automobil, in the following map
同样的，当我遇到时#Automobil，在下图中
Map<String, String> automobilMap = new LinkedHashMap<String, String>();
I want these key-value pairs stored:
我希望存储这些键值对：
PRIM_KEY=registrationNumber
MAKE=manufacturer
TYPE=model
When I read the file, how to store these key-value pairs in two different maps depending upon, in this example, #Personand #Automobil?
当我读文件，如何存储在两个不同的地图，这些键值对，这取决于，在这个例子中，#Person和#Automobil？
EDIT Sample Code:
编辑示例代码：
Scanner scanner = new Scanner(new FileReader("C:/workspace/column-mapping.txt"));
Map<String, String> personMap = new LinkedHashMap<String, String>();
Map<String, String> automobilMap = new LinkedHashMap<String, String>();
String line;
while (scanner.hasNext()) {
line = scanner.next();
if (!line.startsWith("#") && !line.isEmpty()) {
String[] columns = line.split("=");
personMap.put(columns[0], columns[1]);
}
}
System.out.println(personMap);
This way I can put all key-value pairs in one map personMap. But depending upon sections, I want to be able to put it in different maps.
这样我就可以将所有键值对放在一个 map 中personMap。但是根据不同的部分，我希望能够将它放在不同的地图中。
回答by Niles
I want to propose you two different approaches. The first approach is simply solving your problem with a an if case, in the second approach I am supposing you want to store multiple Automobil and multiple Person so I am creating two classes to solve the problem.
我想向您推荐两种不同的方法。第一种方法只是用 if 案例解决您的问题，在第二种方法中，我假设您想要存储多个 Automobil 和多个 Person，因此我创建了两个类来解决问题。
I hope this can be useful, it was interesting to make this code
我希望这很有用，制作这段代码很有趣
First approach
第一种方法
public static void main(String args[]) throws FileNotFoundException{
Scanner scanner = new Scanner(new FileReader("C:/workspace/column-mapping.txt"));
Map<String, String> personMap = new LinkedHashMap<String, String>();
Map<String, String> automobilMap = new LinkedHashMap<String, String>();
String line= scanner.nextLine();
while(scanner.hasNext()){
Map<String, String> currentMap = null;
if(line.equals("#Person")){
currentMap=personMap;
}
if(line.equals("#Automobil")){
currentMap=automobilMap;
}
while(scanner.hasNext()){
line=scanner.nextLine();
if(line.startsWith("#"))
break; //restart the loop
String splitted[] = line.split("=");
currentMap.put(splitted[0], splitted[1]);
}
}
}
Second approach
第二种方法
public static void main(String[] args) throws FileNotFoundException {
Scanner scanner = new Scanner(new FileReader("C:/workspace/column-mapping.txt"));
Map<String, Person> personMap = new LinkedHashMap<String, Person>();
Map<String, Car> automobilMap = new LinkedHashMap<String, Car>();
String line;
while (scanner.hasNextLine()) {
line = scanner.nextLine();
if(line.equals("#Person")){
String primaryKey = scanner.nextLine().split("=")[1];
String sex = scanner.nextLine().split("=")[1];
String years = scanner.nextLine().split("=")[1];
String name = scanner.nextLine().split("=")[1];
personMap.put(primaryKey, new Person(sex,years,name));
}
if(line.equals("#Automobil")){
String primaryKey = scanner.nextLine().split("=")[1];
String make = scanner.nextLine().split("=")[1];
String type = scanner.nextLine().split("=")[1];
automobilMap.put(primaryKey, new Car(make,type));
}
}
Set<String> personKeys = personMap.keySet();
Set<String> automobilKeys = automobilMap.keySet();
for(String k : personKeys){
System.out.println("Person: "+k);
System.out.println(personMap.get(k));
}
for(String k : automobilKeys){
System.out.println("Car: "+k);
System.out.println(automobilMap.get(k));
}
}
The two classes for the second approach
第二种方法的两个类
public class Person {
boolean male; //true for male, false for female
int years;
String name;
String surname;
public Person(String gender, String age, String fullName){
if(gender.equals("male"))
male = true;
else
male = false;
years=Integer.parseInt(age);
String splitted[] = fullName.split(" ");
name = splitted[0];
surname = splitted[1];
}
@Override
public String toString(){
String gender = "male";
if(!male)
gender = "female";
return "SEX = "+gender+"\nYEARS = "+years+"\nNAME = "+name+" "+surname;
}
}
public class Car {
String make;
String type;
public Car(String manufacturer,String model){
make=manufacturer;
type=model;
}
@Override
public String toString(){
return "MAKE = "+make+"\nTYPE = "+type;
}
}
}
回答by SASM
Not the most elegant solution, but got it working.
不是最优雅的解决方案，但让它发挥作用。
Scanner scanner = new Scanner(new FileReader("C:/workspace/column-mapping.txt"));
Map<String, String> personMap = new LinkedHashMap<String, String>();
Map<String, String> automobilMap = new LinkedHashMap<String, String>();
String line;
boolean person = false;
boolean automobil= false;
while (scanner.hasNext()) {
line = scanner.next();
if(line.startsWith("#Person") && !line.isEmpty()){
line = scanner.next();
person = true;
automobil = false;
}
if(line.startsWith("#Automobil") && !line.isEmpty()){
line = scanner.next();
automobil = true;
person = false;
}
if(person){
if (!line.startsWith("#") && !line.isEmpty()) {
String[] columns = line.split("=");
for(String str:columns){
System.out.println(str);
}
personMap.put(columns[0], columns[1]);
}
}
if(automobil){
if (!line.startsWith("#") && !line.isEmpty()) {
String[] columns = line.split("=");
for(String str:columns){
System.out.println(str);
}
automobilMap.put(columns[0], columns[1]);
}
}
}
System.out.println("personMap"+personMap);
System.out.println("automobilMap"+automobilMap);
