Java HashMap迭代未显示键和变量之间的比较
[英]Java HashMap Iteration not showing comparison between key and variable
问题描述
I am trying to iterate through a HashMap and when a duplicate key (key=node coord) is detected I want to give the new node with the same key( coord ) the same nodeID( Hasmap value ). 
我试图通过HashMap进行迭代，并且当检测到重复的键（key = node coord）时，我想给具有相同key（coord）的新节点相同的nodeID（Hasmap value）。 Here is my problem codeblock and my output. 这是我的问题代码块和输出。 As you can see it outputs that the key( keys) and the new key(finishedLine3) have the same value but it will not go into the "if" statement and change the nodeIDs. 如您所见，它输出key（keys）和新key（finishedLine3）具有相同的值，但是不会进入“ if”语句并更改nodeID。
HISTORY: I am comparing with " == " here but have also tried if(keys.equal(finishedLine3)) and get the same result. 历史记录：我在这里与“ ==”进行比较，但也尝试过if（keys.equal（finishedLine3））并获得相同的结果。
I also show in the output that nodes key: -86.88642133.035899 nodes value: 00000001 and nodes key: -86.88642133.035899 nodes value: 00000010 are the same but at no time during the iteration does my logic allow these comparison of the two exact keys go into my "if" block. 我还在输出中显示节点键：-86.88642133.035899节点值：00000001和节点键：-86.88642133.035899节点值：00000010是相同的，但是在迭代过程中，我的逻辑没有允许对这两个精确的比较键进入我的“ if”块。
Here is my code: 这是我的代码：
package com.KatsProject.net;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.text.DecimalFormat;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Set;
public class MakeFile {
public static void main(String[] args) throws IOException {
DecimalFormat df = new DecimalFormat("00000000");
Integer numWords = 0;
Integer numLines = 1;
Integer numNodes =0;
Integer nodeID =0;
Integer counter=0;
String nodesID2 ="";
String newNodeID="";
String header = "road_id #_of_nodes node_id node_x_coord node_y_coord ... end of list";
String finishedLine1 = " ";
String finishedLine2 = " ";
String finishedLine3 = " ";
String finishedLine34 = " ";
String finishedLine = " ";
String roadID= "";
String roadID2= "";
String match=" ";
String match2=" ";
String temp=" ";
BufferedReader br= null;
BufferedWriter bw= null;
HashMap<String, String> nodes = new HashMap<String, String>();
br = new BufferedReader(new FileReader("C:\\Users\\gary\\Desktop\\roads.txt"));
try {
bw = new BufferedWriter(new FileWriter("C:\\Users\\gary\\Desktop\\Secretfile"));
} catch (IOException e) {
System.out.println("Error writing file");
e.printStackTrace();
}
String line = null;
while( (line = br.readLine())!= null )
{
if(numLines > 1){
numWords =0;
nodeID +=1;
newNodeID= df.format(nodeID);
nodesID2 = newNodeID;
String [] tokens = line.split("\\s+");
roadID = tokens[0]; // save roadID for comparison
finishedLine1="";
for(String s :tokens){
numWords+=1;
if(numWords == 1){
// x.setRoadID(roadID);
}
if(numWords ==2 ){
match += s;
}
if(numWords ==3 ){
match2 += s;
//System.out.println(match2+"this is match2 , " + match + " this is match");
}
if(numWords == 4 ){
finishedLine3 += s; //for hash table
finishedLine3.trim();
finishedLine1 += s;
finishedLine1 += " ";
//System.out.println(x.getX_coord()+ " this is x_coord.");
}
if(numWords == 5){
finishedLine3 += s; //for hash table
finishedLine3.trim();
finishedLine1 += s;
finishedLine1 += " ";
String key =finishedLine3;
//System.out.println("It is " + nodes.containsKey(key)+ " that the nodeID for the key : "+ finishedLine3 + " is: " + nodes.get(key)+ " "+ key );
//System.out.println(finishedLine3+ " Is this the line that also includes the roadID #?");
//nodes.put(key,newNodeID );
Set<String> keySet = nodes.keySet();
Iterator<String> keyIterator = keySet.iterator();
//System.out.println("Another iteration starts , this is iteration : "+ nodeID);
bw.write("Another iteration starts , this is iteration : "+ nodeID);
bw.write("\n");
while (keyIterator.hasNext()) {
String keys = keyIterator.next();
//System.out.println( keys);
//System.out.println(" nodes key: " + keys + " nodes value: " + nodes.get(keys));
//System.out.println("Is keys: "+keys + " equal to finishedLine3 : " +finishedLine3);
if (keys.equals(finishedLine3))
{
//System.out.println( "This is finishedLine3 : "+finishedLine3 +" , and it is equal to: " + keys);
newNodeID = nodes.get(keys);
// System.out.println(nodes.get(key) + " this is nodes.get(key) ");
//System.out.println(nodes.get(keys) + " this is nodes.get(keys) ");
//finishedLine2+=nodes.get(finishedLine3);
finishedLine3="";
}
}
nodes.put(key,newNodeID );
match2="";
match="";
}
}
if ((!(roadID.equals(roadID2)))&&(match.equals(match2)))
{
finishedLine+= roadID;
finishedLine+= " ";
finishedLine+=numNodes;
finishedLine+= " ";
finishedLine+=finishedLine2;
finishedLine+="...end of list \n";
bw.write(finishedLine);
bw.write("\n");
finishedLine=" ";
finishedLine2=" ";
finishedLine3=" ";
numNodes=0;
roadID2 = roadID;
//roadID2 = x.roadID;
match="";
match2="";
}
if((roadID.equals(roadID2))||roadID2==""){
//finishedLine2+= x.getNodeID();
finishedLine2+= newNodeID;
//System.out.println( " This is finishedLine2 after inserting newNodeID: "+ newNodeID+" "+ finishedLine2);
//System.out.println(newNodeID + " this is newNodeID copied to finishedLine2 string."+finishedLine2+" checking to see if newNOdeID was changed in string");
//System.out.println(" This is finishedLine1: " +finishedLine1);
finishedLine2+=" ";
finishedLine2 += finishedLine1;
finishedLine2+=" ";
//System.out.println( " This is finishedLine2: "+ finishedLine2);
numNodes+=1;
finishedLine1="";
match2="";
match="";
//System.out.println("this is in if statement");
}
finishedLine3 = "";
}
else{
System.out.print(header+"\n");
bw.write(header + "\n");
numLines+=1;
}
roadID2 = roadID;
match="";
match2="";
}
br.close();
}
}
And here is my output: 这是我的输出：
road_id #_of_nodes node_id node_x_coord node_y_coord ... end of list
This is keys: -86.88642133.035899and this is the : 1 iteration through the while loop
Is keys: -86.88642133.035899 equal to finishedLine3 : -86.88651833.035997?
This is keys: -86.88642133.035899and this is the : 2 iteration through the while loop
Is keys: -86.88642133.035899 equal to finishedLine3 : -86.88657833.03605?
This is keys: -86.88651833.035997and this is the : 3 iteration through the while loop
Is keys: -86.88651833.035997 equal to finishedLine3 : -86.88657833.03605?
This is keys: -86.88642133.035899and this is the : 4 iteration through the while loop
Is keys: -86.88642133.035899 equal to finishedLine3 : -86.88666833.03609?
This is keys: -86.88651833.035997and this is the : 5 iteration through the while loop
Is keys: -86.88651833.035997 equal to finishedLine3 : -86.88666833.03609?
This is keys: -86.88657833.03605and this is the : 6 iteration through the while loop
Is keys: -86.88657833.03605 equal to finishedLine3 : -86.88666833.03609?
This is keys: -86.88642133.035899and this is the : 7 iteration through the while loop
Is keys: -86.88642133.035899 equal to finishedLine3 : -86.88674233.03608?
This is keys: -86.88651833.035997and this is the : 8 iteration through the while loop
Is keys: -86.88651833.035997 equal to finishedLine3 : -86.88674233.03608?
This is keys: -86.88666833.03609and this is the : 9 iteration through the while loop
Is keys: -86.88666833.03609 equal to finishedLine3 : -86.88674233.03608?
This is keys: -86.88657833.03605and this is the : 10 iteration through the while loop
Is keys: -86.88657833.03605 equal to finishedLine3 : -86.88674233.03608?
This is keys: -86.88642133.035899and this is the : 11 iteration through the while loop
Is keys: -86.88642133.035899 equal to finishedLine3 : -86.88679433.036037?
This is keys: -86.88651833.035997and this is the : 12 iteration through the while loop
Is keys: -86.88651833.035997 equal to finishedLine3 : -86.88679433.036037?
This is keys: -86.88674233.03608and this is the : 13 iteration through the while loop
Is keys: -86.88674233.03608 equal to finishedLine3 : -86.88679433.036037?
This is keys: -86.88666833.03609and this is the : 14 iteration through the while loop
Is keys: -86.88666833.03609 equal to finishedLine3 : -86.88679433.036037?
This is keys: -86.88657833.03605and this is the : 15 iteration through the while loop
Is keys: -86.88657833.03605 equal to finishedLine3 : -86.88679433.036037?
This is keys: -86.88642133.035899and this is the : 16 iteration through the while loop
Is keys: -86.88642133.035899 equal to finishedLine3 : -86.88679133.035966?
This is keys: -86.88651833.035997and this is the : 17 iteration through the while loop
Is keys: -86.88651833.035997 equal to finishedLine3 : -86.88679133.035966?
This is keys: -86.88674233.03608and this is the : 18 iteration through the while loop
Is keys: -86.88674233.03608 equal to finishedLine3 : -86.88679133.035966?
This is keys: -86.88679433.036037and this is the : 19 iteration through the while loop
Is keys: -86.88679433.036037 equal to finishedLine3 : -86.88679133.035966?
This is keys: -86.88666833.03609and this is the : 20 iteration through the while loop
Is keys: -86.88666833.03609 equal to finishedLine3 : -86.88679133.035966?
This is keys: -86.88657833.03605and this is the : 21 iteration through the while loop
Is keys: -86.88657833.03605 equal to finishedLine3 : -86.88679133.035966?
This is keys: -86.88642133.035899and this is the : 22 iteration through the while loop
Is keys: -86.88642133.035899 equal to finishedLine3 : -86.88674333.03591?
This is keys: -86.88651833.035997and this is the : 23 iteration through the while loop
Is keys: -86.88651833.035997 equal to finishedLine3 : -86.88674333.03591?
This is keys: -86.88679133.035966and this is the : 24 iteration through the while loop
Is keys: -86.88679133.035966 equal to finishedLine3 : -86.88674333.03591?
This is keys: -86.88674233.03608and this is the : 25 iteration through the while loop
Is keys: -86.88674233.03608 equal to finishedLine3 : -86.88674333.03591?
This is keys: -86.88679433.036037and this is the : 26 iteration through the while loop
Is keys: -86.88679433.036037 equal to finishedLine3 : -86.88674333.03591?
This is keys: -86.88666833.03609and this is the : 27 iteration through the while loop
Is keys: -86.88666833.03609 equal to finishedLine3 : -86.88674333.03591?
This is keys: -86.88657833.03605and this is the : 28 iteration through the while loop
Is keys: -86.88657833.03605 equal to finishedLine3 : -86.88674333.03591?
This is keys: -86.88642133.035899and this is the : 29 iteration through the while loop
Is keys: -86.88642133.035899 equal to finishedLine3 : -86.88668133.035885?
This is keys: -86.88651833.035997and this is the : 30 iteration through the while loop
Is keys: -86.88651833.035997 equal to finishedLine3 : -86.88668133.035885?
This is keys: -86.88674333.03591and this is the : 31 iteration through the while loop
Is keys: -86.88674333.03591 equal to finishedLine3 : -86.88668133.035885?
This is keys: -86.88679133.035966and this is the : 32 iteration through the while loop
Is keys: -86.88679133.035966 equal to finishedLine3 : -86.88668133.035885?
This is keys: -86.88674233.03608and this is the : 33 iteration through the while loop
Is keys: -86.88674233.03608 equal to finishedLine3 : -86.88668133.035885?
This is keys: -86.88679433.036037and this is the : 34 iteration through the while loop
Is keys: -86.88679433.036037 equal to finishedLine3 : -86.88668133.035885?
This is keys: -86.88666833.03609and this is the : 35 iteration through the while loop
Is keys: -86.88666833.03609 equal to finishedLine3 : -86.88668133.035885?
This is keys: -86.88657833.03605and this is the : 36 iteration through the while loop
Is keys: -86.88657833.03605 equal to finishedLine3 : -86.88668133.035885?
This is keys: -86.88642133.035899and this is the : 37 iteration through the while loop
Is keys: -86.88642133.035899 equal to finishedLine3 : -86.88642133.035899?
Thanks to anyone that can help and hope I was clear and concise enough. 感谢任何能够提供帮助并希望我足够清楚和简洁的人。
2 个解决方案
解决方案1
0 2016-02-28 06:23:42
While using the == , you normally imply that the objects are the same. 使用== ，通常意味着对象是相同的。 Therefore, avoid using == for objects in favor of Object equals() but use == for primitives. 因此，避免对对象使用==来支持Object equals()而对基本类型使用== 。 In your case, you should be using keys.equals(finishedLine3) as these are two different objects. 在您的情况下，应使用keys.equals(finishedLine3)因为这是两个不同的对象。 In your problem above, you haven't shown initialization of the finishedLine3 which is probably causing the wrong behavior. 在上面你的问题，你有没有表现出的初始化finishedLine3这可能是导致错误的行为。
解决方案2
0 2016-02-28 07:43:11
I am assuming that you replicated the output of the code you have run. 我假设您复制了已运行的代码的输出。 I would suggest you use Object equals() when comparing two string objects. 我建议您在比较两个字符串对象时使用Object equals（）。 But what I could see in your code is that there is a leading blank space in your key(" -86.88642133.035899" instead of "-86.88642133.035899"). 但是我可以在您的代码中看到的是，您的密钥中有一个前导空格（“ -86.88642133.035899”而不是“ -86.88642133.035899”）。 So you could try avoiding this while creating the HashMap or if you are getting your input from some file you could trim the string, here is a link to the documentation- 因此，您可以在创建HashMap时尝试避免这种情况，或者如果您从某个文件中获取输入，则可以修剪字符串，这是指向文档的链接-
https://docs.oracle.com/javase/7/docs/api/java/lang/String.html#trim() https://docs.oracle.com/javase/7/docs/api/java/lang/String.html#trim（）
Hope this helps. 希望这可以帮助。
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