哈希映射混乱。读取/写入文件。JAVA
迄今为止的代码：哈希映射混乱。读取/写入文件。JAVA,java,file,hashmap,filewriter,Java,File,Hashmap,Filewriter,迄今为止的代码： public class test1 { public static void main(String[] args) throws IOException {
public class test1 {
public static void main(String[] args) throws IOException {
//declare reader and writer
BufferedReader reader = null;
PrintWriter writer = null;
//hash maps to store the data
HashMap<String, String> names = new HashMap<String, String>();
//read the first file and store the data
reader = new BufferedReader(new InputStreamReader(new FileInputStream(new File("IRStudents.txt"))));
String line;
String[] arg;
while ((line = reader.readLine()) != null) {
if (!line.startsWith("-")) {
arg = line.split(" ");
names.put(arg[0], arg[1]);
}
}
reader.close();
//read the second file, merge the data and output the data to the out file
writer = new PrintWriter(new FileOutputStream(new File("File_2.txt")));
reader = new BufferedReader(new InputStreamReader(new FileInputStream(new File("Marks.txt"))));
while((line = reader.readLine()) != null){
arg = line.split(" ");
writer.println(arg[0] + " " + names.get(arg[0]));
writer.println("Marks: " + arg[1]);
writer.println("- - - - - -");
}
writer.flush();
writer.close();
reader.close();
}
}
25220 Fiona
Marks: 68.3 Marks2: 21.2
- - - - - -
25212 Greg
Marks: 70.5 Marks2: 23.43
- - - - - -
25987 Alan
25954 Betty
25654 Chris
25622 David
添加新标记时，使用此选项将其添加到现有标记中：
String key = arg[0];
String secondMarks = arg[1];
String theMarks = names.get(key);
theMarks = theMarks + " Marks2: " + secondMarks;
names.put(key, theMarks);
我想我理解你的问题，如果这是错误的，请告诉我 要求是要有该人在自己的线路上收到的所有标记 System.out stream中有两个打印功能 print和println
arg = line.split(" ");
writer.println(arg[0] + " " + names.get(arg[0]));
writer.print("Marks: " + arg[1]);
for(int i = 2; i < args.length; i++){
writer.println(" Marks" + i + ": " + arg[i]);
}
writer.println("\n- - - - - -");
arg=line.split（“”）；
writer.println（arg[0]+“”+names.get（arg[0]）；
writer.print（“标记：+arg[1]）；
对于（int i=2；ipublic class MarksRecord {
private String subject; // or whatever this variable name should be.
// in your case it should hold value marks1.
private double marks;
}
public final class Student {
private final String rollNumber;
private final String name;
// equals, hashCode, and other methods.
}
Map<Student, ArrayList<MarksRecord>>
Map
Map<String, ArrayList<MarksRecord>>
Map
这样，每当您有一个新的标记文件时，您的数据结构将能够容纳它。您也可以执行以下操作
package toBeDeleted;
import java.util.HashMap;
import java.util.Map;
import java.util.Objects;
public class MarksProcessor {
private final Map<String, Record> map = new HashMap<>();
public static void main(String[] args) {
String fileName = "file1.txt"; // change it to your specific file.
MarksProcessor marksProcessor = new MarksProcessor();
marksProcessor.processFile(fileName, 0);
fileName = "file2.txt";
marksProcessor.processFile(fileName, 1);
marksProcessor.writeData();
}
private void processFile(String fileName, int marksIndex) {
try(/*specify your reader resources here*/) {
// read the first record and get rollNumber, name and marks.
String roll = "valueYouGot";
double value = 0.0; // the value you read.
Record record = map.get(roll);
// if record is null, you need to create one
// and put it into the map.
//record.updateMarks(marksndex, value);
}
}
private void writeData() {
// if this needs to be written to a file/stream, create a writer.
for (Map.Entry<String, Record> entry : map.entrySet()) {
String roll = entry.getKey();
Record record = entry.getValue();
if (record != null) {
String name = record.getName();
double marks1 = record.getMarks(0);
double marks2 = record.getMarks(1);
// Now you have all the values. Print them
// however you like. Wherever you like.
}
}
}
static class Record {
private String name;
private double[] marks = new double[2];
Record(String name) {
this.name = name;
}
public String getName() {
return name;
}
public double getMarks(int index) {
if (index < 0 || index > 1)
throw new IllegalArgumentException("index should be 0 or 1 but"
+ " the supplied index was " + index);
return marks[index];
}
public void updateMarks(int index, double value ) {
if (index < 0 || index > 1)
throw new IllegalArgumentException("index should be 0 or 1 but"
+ " the supplied index was " + index);
marks[index] = value;
}
@Override
public String toString() {
return "the way you want to type your output";
}
}
}
要删除的包；
导入java.util.HashMap；
导入java.util.Map；
导入java.util.Objects；
公共类标记处理器{
私有最终映射=新HashMap（）；
公共静态void main（字符串[]args）{
String fileName=“file1.txt”；//将其更改为您的特定文件。
MarksProcessor MarksProcessor=新的MarksProcessor（）；
marksProcessor.processFile（文件名，0）；
fileName=“file2.txt”；
marksProcessor.processFile（文件名，1）；
marksProcessor.writeData（）；
}
私有void进程文件（字符串文件名，int-marksIndex）{
尝试（/*在此处指定您的读卡器资源*/）{
//读取第一条记录并获取卷号、名称和标记。
String roll=“valueYouGot”；
double value=0.0；//读取的值。
记录=map.get（roll）；
//如果记录为空，则需要创建一个
//把它放到地图上。
//record.updateMarks（marksndex，value）；
}
}
私有无效写入数据（）{
//如果需要将其写入文件/流，请创建一个writer。
对于（Map.Entry:Map.entrySet（））{
字符串roll=entry.getKey（）；
Record=entry.getValue（）；
if（记录！=null）{
String name=record.getName（）；
双标记s1=记录.getMarks（0）；
双标记2=记录.getMarks（1）；
//现在你有了所有的值。打印它们
//不管你喜欢什么，无论你喜欢哪里。
}
}
}
静态课堂记录{
私有字符串名称；
专用双精度[]标记=新双精度[2]；
记录（字符串名称）{
this.name=名称；
}
公共字符串getName（）{
返回名称；
}
公共双标记（整数索引）{
如果（索引<0 | |索引>1）
抛出新的IllegalArgumentException（“索引应为0或1，但”
+“提供的指数为”+指数）；
返回标记[索引]；
}
公共void更新标记（整数索引，双精度值）{
如果（索引<0 | |索引>1）
抛出新的IllegalArgumentException（“索引应为0或1，但”
+“提供的指数为”+指数）；
标记[索引]=值；
}
@凌驾
公共字符串toString（）{
返回“输入输出的方式”；
}
}
}
package toBeDeleted;
import java.util.HashMap;
import java.util.Map;
import java.util.Objects;
public class MarksProcessor {
private final Map<String, Record> map = new HashMap<>();
public static void main(String[] args) {
String fileName = "file1.txt"; // change it to your specific file.
MarksProcessor marksProcessor = new MarksProcessor();
marksProcessor.processFile(fileName, 0);
fileName = "file2.txt";
marksProcessor.processFile(fileName, 1);
marksProcessor.writeData();
}
private void processFile(String fileName, int marksIndex) {
try(/*specify your reader resources here*/) {
// read the first record and get rollNumber, name and marks.
String roll = "valueYouGot";
double value = 0.0; // the value you read.
Record record = map.get(roll);
// if record is null, you need to create one
// and put it into the map.
//record.updateMarks(marksndex, value);
}
}
private void writeData() {
// if this needs to be written to a file/stream, create a writer.
for (Map.Entry<String, Record> entry : map.entrySet()) {
String roll = entry.getKey();
Record record = entry.getValue();
if (record != null) {
String name = record.getName();
double marks1 = record.getMarks(0);
double marks2 = record.getMarks(1);
// Now you have all the values. Print them
// however you like. Wherever you like.
}
}
}
static class Record {
private String name;
private double[] marks = new double[2];
Record(String name) {
this.name = name;
}
public String getName() {
return name;
}
public double getMarks(int index) {
if (index < 0 || index > 1)
throw new IllegalArgumentException("index should be 0 or 1 but"
+ " the supplied index was " + index);
return marks[index];
}
public void updateMarks(int index, double value ) {
if (index < 0 || index > 1)
throw new IllegalArgumentException("index should be 0 or 1 but"
+ " the supplied index was " + index);
marks[index] = value;
}
@Override
public String toString() {
return "the way you want to type your output";
}
}
}