Java Generating All Key Value Pairs From List

17.12.2020by admin

The Java Keytool is a command line tool which can generate public key / private key pairs and store them in a Java KeyStore. The Keytool executable is distributed with the Java SDK (or JRE), so if you have an SDK installed you will also have the Keytool executable.

Java Key Value Pair List
Java Name Value Pair Collection
Key Value Pair In Java

Java 8 Create list of pairs from List of items. Java does not have Pair and groupBy uses AtomicInteger trick. List 2 Pairs. Skip to content. All gists Back to GitHub. Mar 20, 2018 Spring Cache is nothing but a store of key-value pairs, where values are the ones returned from @Cacheable methods, whereas, for keys there has to be some strategy to generate them. By default Spring uses a simple key generation based on the following algorithm: If @Cacheable method has no arguments then SimpleKey.EMPTY is used as key. Here we use it in a List. We store pairs of values in a single List. Two Lists could be used, but that might complicate matters. Part 1: Here we initialize a List of pairs. Each pair has 2 types separated by a comma (string, int). The Dictionary has an enumerator that returns each key and value in a KeyValuePair, one at a time.

The Keytool executable is called keytool. To execute it, open a command line (cmd, console, shell etc.). and change directory into the bin directory of your Java SDK installation. Type keytool followed by pressing the Enter key. You should see something similar to this:

As you can see, keytool supports a set of commands to work with keys, certificates and key stores. This Java Keytool tutorial will cover the most commonly used of these commands.

Keytool Scripts

Keytool commands take a lot of arguments which may be hard to remember to set correctly. Therefore it is a good idea to create some Keytool CMD or Shell scripts with the Keytool commands in. The scripts makes it easier to re-execute the keytool commands later on, and makes it possible to go back later and see how a KeyStore was generated.

Generate Key Pair

Generating a public key / private key pair is one of the most common tasks to use the Java Keytool for. The generated key pair is inserted into a Java KeyStore file as a self signed key pair. Here is the general command line format for generating a key pair with the Keytool:

The arguments are explained in the Keytool Arguments section. Not all of these arguments are needed. Many are optional. The Keytool will tell you if you are missing a required argument.

The line breaks should not be included in the final command. The line breaks are only there to make the command format easier to read here.

Here is an example keytool -genkeypair command. Remember to remove the line breaks before trying it out!

Export Certificate

The Java Keytool can also export certificates stored in a KeyStore. Here is how the Keytool command looks for exporting certificates:

The arguments are explained in the Keytool Arguments section. Not all of these arguments are needed. Many are optional. The Keytool will tell you if you are missing a required argument.

Here is a Keytool command example that exports the certificate for a key pair. Remember to remove the line breaks when entering the command on the command line.

Import Certificate

The Java Keytool can also import certificates into a KeyStore. Wifi password key generator online. Here is how the Keytool command looks for importing certificates:

The arguments are explained in the Keytool Arguments section. Not all of these arguments are needed. Many are optional. The Keytool will tell you if you are missing a required argument.

Here is an example Keytool command that imports a certificate into a KeyStore. Remember to remove the line breaks when entering the command on the command line.

List KeyStore Entries

To list the entries in a Java KeyStore you can use the Keytool -list command. Here is the format for the Keytool -list command. The line breaks are only here to make the command format easier to read. Remove the line breaks before running the command.

The arguments are explained in the Keytool Arguments section. Not all of these arguments are needed. Many are optional. The Keytool will tell you if you are missing a required argument.

Here is a Keytool -list command example. Remember to remove the line breaks!

This Keytool -list command will list all entries in the given KeyStore. The output of running this Keytool -list command will look similar to this:

If you include an -alias argument in the Keytool -list command, then only the entry matching the given alias will get listed. Here is an example Keytool -list command with an -alias argument:

The output of running the above Keytool -list command will look similar to this:

Delete KeyStore Entry

The Keytool has a command that can delete a key entry in a Java KeyStore. The Keytool command for deleting keys is -delete. Here is the format of the Keytool -delete command:

The arguments are explained in the Keytool Arguments section. Not all of these arguments are needed. Many are optional. The Keytool will tell you if you are missing a required argument.

Here is a Keytool -delete command example. Remember to remove the line breaks before running it!

This Keytool -delete command will remove the KeyStore entry with the alias testkey from the KeyStore stored in the file keystore.jks .

Generate a Certificate Request

The Java Keytool can generate a certificate request using the -certreq command. A certificate request is a request for a certificate authority (CA) to create a public certificate for your organization. Once generated, the certificate request should be sent to the CA you want to create a certificate for you (e.g. Verisign, Thawte, or some other CA).

Before you can generate a certificate request for a private key, public key pair, you must have generated that private key, public key pair into the Keystore (or imported it). See elsewhere in this Java Keytool tutorial to see how to do that. Desktop clock 2.0.0.

Here is the command format for generating a certificate request. Remember to remove all line breaks when trying out this command:

The arguments are explained in the Keytool Arguments section. Not all of these arguments are needed. Many are optional. The Keytool will tell you if you are missing a required argument.

Here is a Java Keytool -certreq command example:

This command will generate a certificate request for the key stored with alias testkey in the keystore file keystore.jks, and write the certificate request into the file named certreq.certreq .

Half life product key generator. Remember, the line breaks are only included to make the command easier to read. Omit them when typing in the command on the command line yourself.

Keytool Arguments

Below is a list of the arguments the various Keytool commands take. Please keep in mind that not all commands accept all of these arguments. Look at the concrete command to see what arguments it takes.

Argument	Description
`-alias`	The name in the Java KeyStore the generated key should be identified by. Remember, an alias can only point to one key.
`-keyalg`	The name of the algorithm used to generate the key. A common value is `RSA` meaning the RSA algorithm should be used to generate the key pair.
`-keysize`	The size in bits of the key to generate. Normally key sizes are multiples of 8 which aligns with a number of bytes. Additionally, different algorithms may only support certain preset key sizes. You will need to check what the key size should be for the key you want to generate.
`-sigalg`	The signature algorithm used to sign the key pair.
`-dname`	The Distinguished Name from the X.500 standard. This name will be associated with the alias for this key pair in the KeyStore. The `dname` is also used as the 'issuer' and 'subject' fields in the self signed certificate.
`-keypass`	The key pair password needed to access this specific key pair within the KeyStore.
`-validity`	The number of days the certificate attached to the key pair should be valid.
`-storetype`	The file format the KeyStore should be saved in. The default is `JKS`. Another option is the value `PKCS11` which represents the standard PKCS11 format.
`-keystore`	The name of the KeyStore file to store the generated key pair in. If the file does not exist, it will be created.
`-file`	The name of the file to read from or write to (certificate or certificate request).
`-storepass`	The password for the whole KeyStore. Anyone who wants to open this KeyStore later will need this password. The `storepass` is not the same as the `keypass`. The `keypass` password only counts for a single key. You will need both the KeyStore password and the key password to access any given key stored in a KeyStore.
`-rfc`	If this flag is included (it has no value following it) then Keytool will use a textual format rather than binary format e.g. for export or import of certificates. The value `-rfc` refers to the RFC 1421 standard.
`-providerName`	The name of the cryptographic API provider you want to use (if any) when generating the key pair. The provider name must be listed in the Java security property files for this to work.
`-providerClass`	The name of the root class of the cryptographic API provider you want to use. Use this when the provider name is not listed in the Java security property files.
`-providerArg`	Arguments you can pass to your cryptographic provider at initialization (if needed by the provider).
`-v`	Short for 'verbose' (?!?), meaning the Keytool will print out a lot of extra information into the command line in a humanly readable format.
`-protected`	Specifies whether or not the KeyStore password should be provided by some external mechanism like a pin reader. Valid values are `true` and `false`.
`-Jjavaoption`	A Java option string (Java VM options) which can be passed to the Java VM that generates the key pair and creates the KeyStore.

Right 1

Greenhorn

posted 8 years ago

I'm trying to create a HashMap, loop through that HashMap, and finally, I'm trying create an ArrayList of key/value pairs -- from the HashMap -- that contain within its value set a parameter value. I realize that might be a little hard to understand, so I've provided my code to make sense of what I'm trying to accomplish.

package data; import java.util.ArrayList; import java.util.HashMap; import java.util.Iterator; import java.util.Map; public class ProductInventory { private Map <String, ArrayList<String>> product; private ArrayList <String> buildProduct; private ArrayList <ArrayList<String>> addProduct; public ProductInventory() { /** Set default values **/ product = new <String, ArrayList<String>> HashMap(); buildProduct = new ArrayList<String> (); addProduct = new ArrayList<ArrayList <String>> (); /** START - Create ArrayList for each item and add to HashMap**/ ArrayList <String> c1 = new ArrayList<String>(); ArrayList <String> c2 = new ArrayList<String>(); c1.add('computer'); c1.add('Apple'); c1.add('iPad2'); c1.add('499.00'); c2.add('computer'); c2.add('Asus'); c2.add('Zenbook'); c2.add('1449.00'); ArrayList <String> tv1 = new ArrayList<String>(); ArrayList <String> tv2 = new ArrayList<String>(); tv1.add('television'); tv1.add('Panasonic'); tv1.add('Viera'); tv1.add('899.00'); tv2.add('television'); tv2.add('Samsung'); tv2.add('Series 6'); tv2.add('1597.00'); ArrayList <String> a1 = new ArrayList<String>(); ArrayList <String> a2 = new ArrayList<String>(); a1.add('audio'); a1.add('Bose'); a1.add('321 GS Series III'); a1.add('999.00'); a2.add('audio'); a2.add('Onkyo'); a2.add('HT-S3400'); a2.add('329.00'); /** END - Create ArrayList for each item and add to HashMap **/ /** Add entrys to HashMap **/ product.put('CMC769LLA',c1); product.put('CUX31EDH72',c2); product.put('TVTCL50E3',tv1); product.put('TVUN55D6000',tv2); product.put('A321GSIIIBK',a1); product.put('AHTS3400',a2); } /** For the sake of this example, the productAttribute parameter will be equal to 'computer' **/ public void setProducts(String productAttribute) { for (Map.Entry <String, ArrayList<String>> entry : product.entrySet()) /** Loop through all entrys in the HashMap **/ { for (String s: entry.getValue()) /** Loop through all values in HashMap**/ { /** Add product attributes **/ if (s.equals(productAttribute)) /** Check to see if param exists in the value set**/ { /** Add key to buildProduct ArrayList **/ buildProduct.add(entry.getKey()); /*Loop through values of the corresponding key and add to buildProduct*/ for (Iterator<String> i = entry.getValue().iterator(); i.hasNext();) { Object item = i.next(); buildProduct.add(item.toString()); } /** Add buildProduct arrayList to product arrayList **/ addProduct.add(buildProduct); break; /** Exit nested loop**/ } } } } }

For the desired output we can assume that the productAttribute parameter value is 'Computer'.
Current output of the addProduct ArrayList:

Desired output of the addProduct ArrayList:

I can't seem to figure out what I'm doing wrong. Any help would be greatly appreciated.

Marshal

posted 8 years ago

So you have a map which maps a String to a list of Strings. And if I understand your example right, you want to mutate that into a list of lists of Strings, where each of the inner lists comprises a key of the map followed by the list it's mapped to?
Well, looking at the lists of Strings you have in your example, I don't understand why they are lists of Strings. To me they ought to be some kind of objects which are designed specifically for these products, because obviously the first entry in the list is some kind of a category, the second entry is a manufacturer, and so on. Just putting those things in a list is a misuse of lists.
And likewise I don't see the point of making a slightly different list which just has the product code on the front. Perhaps it should be part of the product object which I was just suggesting. Making a list of products would make a lot of sense once you've done that, which is basically your non-OO requirement anyway.

Greenhorn

posted 8 years ago

Thanks for the reply Paul. Yes, your understanding of what I'm trying to do is correct. Is there any chance you could provide some pseudo code on a better way of accomplishing the task at hand?

Java Key Value Pair List

Saloon Keeper

Java Name Value Pair Collection

posted 8 years ago

Key Value Pair In Java

This might be the beginnings of such a class. For the string types, other custom-made classes may be more appropriate; that depends on the design of your app and your requirements.