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I know this question is old, but it is the first search result on google to "java read/write to registry". Recently I found this amazing piece of code which:
This is pure, Java code.
It uses reflection to work, by actually accessing the private methods in the java.util.prefs.Preferences class. The internals of this class are complicated, but the class itself is very easy to use.
For example, the following code obtains the exact windows distribution from the registry:
String value = WinRegistry.readString (
WinRegistry.HKEY_LOCAL_MACHINE, //HKEY
"SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion", //Key
"ProductName"); //ValueName
System.out.println("Windows Distribution = " + value);
Here is the original class. Just copy paste it and it should work:
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.Map;
import java.util.ArrayList;
import java.util.List;
import java.util.prefs.Preferences;
public class WinRegistry {
public static final int HKEY_CURRENT_USER = 0x80000001;
public static final int HKEY_LOCAL_MACHINE = 0x80000002;
public static final int REG_SUCCESS = 0;
public static final int REG_NOTFOUND = 2;
public static final int REG_ACCESSDENIED = 5;
private static final int KEY_ALL_ACCESS = 0xf003f;
private static final int KEY_READ = 0x20019;
private static final Preferences userRoot = Preferences.userRoot();
private static final Preferences systemRoot = Preferences.systemRoot();
private static final Class<? extends Preferences> userClass = userRoot.getClass();
private static final Method regOpenKey;
private static final Method regCloseKey;
private static final Method regQueryValueEx;
private static final Method regEnumValue;
private static final Method regQueryInfoKey;
private static final Method regEnumKeyEx;
private static final Method regCreateKeyEx;
private static final Method regSetValueEx;
private static final Method regDeleteKey;
private static final Method regDeleteValue;
static {
try {
regOpenKey = userClass.getDeclaredMethod("WindowsRegOpenKey",
new Class[] { int.class, byte[].class, int.class });
regOpenKey.setAccessible(true);
regCloseKey = userClass.getDeclaredMethod("WindowsRegCloseKey",
new Class[] { int.class });
regCloseKey.setAccessible(true);
regQueryValueEx = userClass.getDeclaredMethod("WindowsRegQueryValueEx",
new Class[] { int.class, byte[].class });
regQueryValueEx.setAccessible(true);
regEnumValue = userClass.getDeclaredMethod("WindowsRegEnumValue",
new Class[] { int.class, int.class, int.class });
regEnumValue.setAccessible(true);
regQueryInfoKey = userClass.getDeclaredMethod("WindowsRegQueryInfoKey1",
new Class[] { int.class });
regQueryInfoKey.setAccessible(true);
regEnumKeyEx = userClass.getDeclaredMethod(
"WindowsRegEnumKeyEx", new Class[] { int.class, int.class,
int.class });
regEnumKeyEx.setAccessible(true);
regCreateKeyEx = userClass.getDeclaredMethod(
"WindowsRegCreateKeyEx", new Class[] { int.class,
byte[].class });
regCreateKeyEx.setAccessible(true);
regSetValueEx = userClass.getDeclaredMethod(
"WindowsRegSetValueEx", new Class[] { int.class,
byte[].class, byte[].class });
regSetValueEx.setAccessible(true);
regDeleteValue = userClass.getDeclaredMethod(
"WindowsRegDeleteValue", new Class[] { int.class,
byte[].class });
regDeleteValue.setAccessible(true);
regDeleteKey = userClass.getDeclaredMethod(
"WindowsRegDeleteKey", new Class[] { int.class,
byte[].class });
regDeleteKey.setAccessible(true);
}
catch (Exception e) {
throw new RuntimeException(e);
}
}
private WinRegistry() { }
/**
* Read a value from key and value name
* @param hkey HKEY_CURRENT_USER/HKEY_LOCAL_MACHINE
* @param key
* @param valueName
* @return the value
* @throws IllegalArgumentException
* @throws IllegalAccessException
* @throws InvocationTargetException
*/
public static String readString(int hkey, String key, String valueName)
throws IllegalArgumentException, IllegalAccessException,
InvocationTargetException
{
if (hkey == HKEY_LOCAL_MACHINE) {
return readString(systemRoot, hkey, key, valueName);
}
else if (hkey == HKEY_CURRENT_USER) {
return readString(userRoot, hkey, key, valueName);
}
else {
throw new IllegalArgumentException("hkey=" + hkey);
}
}
/**
* Read value(s) and value name(s) form given key
* @param hkey HKEY_CURRENT_USER/HKEY_LOCAL_MACHINE
* @param key
* @return the value name(s) plus the value(s)
* @throws IllegalArgumentException
* @throws IllegalAccessException
* @throws InvocationTargetException
*/
public static Map<String, String> readStringValues(int hkey, String key)
throws IllegalArgumentException, IllegalAccessException,
InvocationTargetException
{
if (hkey == HKEY_LOCAL_MACHINE) {
return readStringValues(systemRoot, hkey, key);
}
else if (hkey == HKEY_CURRENT_USER) {
return readStringValues(userRoot, hkey, key);
}
else {
throw new IllegalArgumentException("hkey=" + hkey);
}
}
/**
* Read the value name(s) from a given key
* @param hkey HKEY_CURRENT_USER/HKEY_LOCAL_MACHINE
* @param key
* @return the value name(s)
* @throws IllegalArgumentException
* @throws IllegalAccessException
* @throws InvocationTargetException
*/
public static List<String> readStringSubKeys(int hkey, String key)
throws IllegalArgumentException, IllegalAccessException,
InvocationTargetException
{
if (hkey == HKEY_LOCAL_MACHINE) {
return readStringSubKeys(systemRoot, hkey, key);
}
else if (hkey == HKEY_CURRENT_USER) {
return readStringSubKeys(userRoot, hkey, key);
}
else {
throw new IllegalArgumentException("hkey=" + hkey);
}
}
/**
* Create a key
* @param hkey HKEY_CURRENT_USER/HKEY_LOCAL_MACHINE
* @param key
* @throws IllegalArgumentException
* @throws IllegalAccessException
* @throws InvocationTargetException
*/
public static void createKey(int hkey, String key)
throws IllegalArgumentException, IllegalAccessException,
InvocationTargetException
{
int [] ret;
if (hkey == HKEY_LOCAL_MACHINE) {
ret = createKey(systemRoot, hkey, key);
regCloseKey.invoke(systemRoot, new Object[] { new Integer(ret[0]) });
}
else if (hkey == HKEY_CURRENT_USER) {
ret = createKey(userRoot, hkey, key);
regCloseKey.invoke(userRoot, new Object[] { new Integer(ret[0]) });
}
else {
throw new IllegalArgumentException("hkey=" + hkey);
}
if (ret[1] != REG_SUCCESS) {
throw new IllegalArgumentException("rc=" + ret[1] + " key=" + key);
}
}
/**
* Write a value in a given key/value name
* @param hkey
* @param key
* @param valueName
* @param value
* @throws IllegalArgumentException
* @throws IllegalAccessException
* @throws InvocationTargetException
*/
public static void writeStringValue
(int hkey, String key, String valueName, String value)
throws IllegalArgumentException, IllegalAccessException,
InvocationTargetException
{
if (hkey == HKEY_LOCAL_MACHINE) {
writeStringValue(systemRoot, hkey, key, valueName, value);
}
else if (hkey == HKEY_CURRENT_USER) {
writeStringValue(userRoot, hkey, key, valueName, value);
}
else {
throw new IllegalArgumentException("hkey=" + hkey);
}
}
/**
* Delete a given key
* @param hkey
* @param key
* @throws IllegalArgumentException
* @throws IllegalAccessException
* @throws InvocationTargetException
*/
public static void deleteKey(int hkey, String key)
throws IllegalArgumentException, IllegalAccessException,
InvocationTargetException
{
int rc = -1;
if (hkey == HKEY_LOCAL_MACHINE) {
rc = deleteKey(systemRoot, hkey, key);
}
else if (hkey == HKEY_CURRENT_USER) {
rc = deleteKey(userRoot, hkey, key);
}
if (rc != REG_SUCCESS) {
throw new IllegalArgumentException("rc=" + rc + " key=" + key);
}
}
/**
* delete a value from a given key/value name
* @param hkey
* @param key
* @param value
* @throws IllegalArgumentException
* @throws IllegalAccessException
* @throws InvocationTargetException
*/
public static void deleteValue(int hkey, String key, String value)
throws IllegalArgumentException, IllegalAccessException,
InvocationTargetException
{
int rc = -1;
if (hkey == HKEY_LOCAL_MACHINE) {
rc = deleteValue(systemRoot, hkey, key, value);
}
else if (hkey == HKEY_CURRENT_USER) {
rc = deleteValue(userRoot, hkey, key, value);
}
if (rc != REG_SUCCESS) {
throw new IllegalArgumentException("rc=" + rc + " key=" + key + " value=" + value);
}
}
// =====================
private static int deleteValue
(Preferences root, int hkey, String key, String value)
throws IllegalArgumentException, IllegalAccessException,
InvocationTargetException
{
int[] handles = (int[]) regOpenKey.invoke(root, new Object[] {
new Integer(hkey), toCstr(key), new Integer(KEY_ALL_ACCESS) });
if (handles[1] != REG_SUCCESS) {
return handles[1]; // can be REG_NOTFOUND, REG_ACCESSDENIED
}
int rc =((Integer) regDeleteValue.invoke(root,
new Object[] {
new Integer(handles[0]), toCstr(value)
})).intValue();
regCloseKey.invoke(root, new Object[] { new Integer(handles[0]) });
return rc;
}
private static int deleteKey(Preferences root, int hkey, String key)
throws IllegalArgumentException, IllegalAccessException,
InvocationTargetException
{
int rc =((Integer) regDeleteKey.invoke(root,
new Object[] { new Integer(hkey), toCstr(key) })).intValue();
return rc; // can REG_NOTFOUND, REG_ACCESSDENIED, REG_SUCCESS
}
private static String readString(Preferences root, int hkey, String key, String value)
throws IllegalArgumentException, IllegalAccessException,
InvocationTargetException
{
int[] handles = (int[]) regOpenKey.invoke(root, new Object[] {
new Integer(hkey), toCstr(key), new Integer(KEY_READ) });
if (handles[1] != REG_SUCCESS) {
return null;
}
byte[] valb = (byte[]) regQueryValueEx.invoke(root, new Object[] {
new Integer(handles[0]), toCstr(value) });
regCloseKey.invoke(root, new Object[] { new Integer(handles[0]) });
return (valb != null ? new String(valb).trim() : null);
}
private static Map<String,String> readStringValues
(Preferences root, int hkey, String key)
throws IllegalArgumentException, IllegalAccessException,
InvocationTargetException
{
HashMap<String, String> results = new HashMap<String,String>();
int[] handles = (int[]) regOpenKey.invoke(root, new Object[] {
new Integer(hkey), toCstr(key), new Integer(KEY_READ) });
if (handles[1] != REG_SUCCESS) {
return null;
}
int[] info = (int[]) regQueryInfoKey.invoke(root,
new Object[] { new Integer(handles[0]) });
int count = info[0]; // count
int maxlen = info[3]; // value length max
for(int index=0; index<count; index++) {
byte[] name = (byte[]) regEnumValue.invoke(root, new Object[] {
new Integer
(handles[0]), new Integer(index), new Integer(maxlen + 1)});
String value = readString(hkey, key, new String(name));
results.put(new String(name).trim(), value);
}
regCloseKey.invoke(root, new Object[] { new Integer(handles[0]) });
return results;
}
private static List<String> readStringSubKeys
(Preferences root, int hkey, String key)
throws IllegalArgumentException, IllegalAccessException,
InvocationTargetException
{
List<String> results = new ArrayList<String>();
int[] handles = (int[]) regOpenKey.invoke(root, new Object[] {
new Integer(hkey), toCstr(key), new Integer(KEY_READ)
});
if (handles[1] != REG_SUCCESS) {
return null;
}
int[] info = (int[]) regQueryInfoKey.invoke(root,
new Object[] { new Integer(handles[0]) });
int count = info[0]; // Fix: info[2] was being used here with wrong results. Suggested by davenpcj, confirmed by Petrucio
int maxlen = info[3]; // value length max
for(int index=0; index<count; index++) {
byte[] name = (byte[]) regEnumKeyEx.invoke(root, new Object[] {
new Integer
(handles[0]), new Integer(index), new Integer(maxlen + 1)
});
results.add(new String(name).trim());
}
regCloseKey.invoke(root, new Object[] { new Integer(handles[0]) });
return results;
}
private static int [] createKey(Preferences root, int hkey, String key)
throws IllegalArgumentException, IllegalAccessException,
InvocationTargetException
{
return (int[]) regCreateKeyEx.invoke(root,
new Object[] { new Integer(hkey), toCstr(key) });
}
private static void writeStringValue
(Preferences root, int hkey, String key, String valueName, String value)
throws IllegalArgumentException, IllegalAccessException,
InvocationTargetException
{
int[] handles = (int[]) regOpenKey.invoke(root, new Object[] {
new Integer(hkey), toCstr(key), new Integer(KEY_ALL_ACCESS) });
regSetValueEx.invoke(root,
new Object[] {
new Integer(handles[0]), toCstr(valueName), toCstr(value)
});
regCloseKey.invoke(root, new Object[] { new Integer(handles[0]) });
}
// utility
private static byte[] toCstr(String str) {
byte[] result = new byte[str.length() + 1];
for (int i = 0; i < str.length(); i++) {
result[i] = (byte) str.charAt(i);
}
result[str.length()] = 0;
return result;
}
}
Original Author: Apache.
Library Source: https://github.com/apache/npanday/tree/trunk/components/dotnet-registry/src/main/java/npanday/registry
You don't actually need a 3rd party package. Windows has a reg utility for all registry operations. To get the command format, go to the DOS propmt and type:
reg /?
You can invoke reg through the Runtime class:
Runtime.getRuntime().exec("reg <your parameters here>");
Editing keys and adding new ones is straightforward using the command above. To read the registry, you need to get reg's output, and it's a little tricky. Here's the code:
import java.io.IOException;
import java.io.InputStream;
import java.io.StringWriter;
/**
* @author Oleg Ryaboy, based on work by Miguel Enriquez
*/
public class WindowsReqistry {
/**
*
* @param location path in the registry
* @param key registry key
* @return registry value or null if not found
*/
public static final String readRegistry(String location, String key){
try {
// Run reg query, then read output with StreamReader (internal class)
Process process = Runtime.getRuntime().exec("reg query " +
'"'+ location + "\" /v " + key);
StreamReader reader = new StreamReader(process.getInputStream());
reader.start();
process.waitFor();
reader.join();
String output = reader.getResult();
// Output has the following format:
// \n<Version information>\n\n<key>\t<registry type>\t<value>
if( ! output.contains("\t")){
return null;
}
// Parse out the value
String[] parsed = output.split("\t");
return parsed[parsed.length-1];
}
catch (Exception e) {
return null;
}
}
static class StreamReader extends Thread {
private InputStream is;
private StringWriter sw= new StringWriter();
public StreamReader(InputStream is) {
this.is = is;
}
public void run() {
try {
int c;
while ((c = is.read()) != -1)
sw.write(c);
}
catch (IOException e) {
}
}
public String getResult() {
return sw.toString();
}
}
public static void main(String[] args) {
// Sample usage
String value = WindowsReqistry.readRegistry("HKCU\\Software\\Microsoft\\Windows\\CurrentVersion\\"
+ "Explorer\\Shell Folders", "Personal");
System.out.println(value);
}
}
Java Native Access (JNA) is an excellent project for working with native libraries and has support for the Windows registry in the platform library (platform.jar) through Advapi32Util and Advapi32.
Update: Here's a snippet with some examples of how easy it is to use JNA to work with the Windows registry using JNA 3.4.1,
import com.sun.jna.platform.win32.Advapi32Util;
import com.sun.jna.platform.win32.WinReg;
public class WindowsRegistrySnippet {
public static void main(String[] args) {
// Read a string
String productName = Advapi32Util.registryGetStringValue(
WinReg.HKEY_LOCAL_MACHINE, "SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion", "ProductName");
System.out.printf("Product Name: %s\n", productName);
// Read an int (& 0xFFFFFFFFL for large unsigned int)
int timeout = Advapi32Util.registryGetIntValue(
WinReg.HKEY_LOCAL_MACHINE, "SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion\\Windows", "ShutdownWarningDialogTimeout");
System.out.printf("Shutdown Warning Dialog Timeout: %d (%d as unsigned long)\n", timeout, timeout & 0xFFFFFFFFL);
// Create a key and write a string
Advapi32Util.registryCreateKey(WinReg.HKEY_CURRENT_USER, "SOFTWARE\\StackOverflow");
Advapi32Util.registrySetStringValue(WinReg.HKEY_CURRENT_USER, "SOFTWARE\\StackOverflow", "url", "http://stackoverflow.com/a/6287763/277307");
// Delete a key
Advapi32Util.registryDeleteKey(WinReg.HKEY_CURRENT_USER, "SOFTWARE\\StackOverflow");
}
}
I've incremented the Pure java code originally posted by David to allow acessing the 32-bits section of the registry from a 64-bit JVM, and vice-versa. I don't think any of the other answers address this.
Here it is:
/**
* Pure Java Windows Registry access.
* Modified by petrucio@stackoverflow(828681) to add support for
* reading (and writing but not creating/deleting keys) the 32-bits
* registry view from a 64-bits JVM (KEY_WOW64_32KEY)
* and 64-bits view from a 32-bits JVM (KEY_WOW64_64KEY).
*****************************************************************************/
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.Map;
import java.util.ArrayList;
import java.util.List;
import java.util.prefs.Preferences;
public class WinRegistry {
public static final int HKEY_CURRENT_USER = 0x80000001;
public static final int HKEY_LOCAL_MACHINE = 0x80000002;
public static final int REG_SUCCESS = 0;
public static final int REG_NOTFOUND = 2;
public static final int REG_ACCESSDENIED = 5;
public static final int KEY_WOW64_32KEY = 0x0200;
public static final int KEY_WOW64_64KEY = 0x0100;
private static final int KEY_ALL_ACCESS = 0xf003f;
private static final int KEY_READ = 0x20019;
private static Preferences userRoot = Preferences.userRoot();
private static Preferences systemRoot = Preferences.systemRoot();
private static Class<? extends Preferences> userClass = userRoot.getClass();
private static Method regOpenKey = null;
private static Method regCloseKey = null;
private static Method regQueryValueEx = null;
private static Method regEnumValue = null;
private static Method regQueryInfoKey = null;
private static Method regEnumKeyEx = null;
private static Method regCreateKeyEx = null;
private static Method regSetValueEx = null;
private static Method regDeleteKey = null;
private static Method regDeleteValue = null;
static {
try {
regOpenKey = userClass.getDeclaredMethod("WindowsRegOpenKey", new Class[] { int.class, byte[].class, int.class });
regOpenKey.setAccessible(true);
regCloseKey = userClass.getDeclaredMethod("WindowsRegCloseKey", new Class[] { int.class });
regCloseKey.setAccessible(true);
regQueryValueEx= userClass.getDeclaredMethod("WindowsRegQueryValueEx",new Class[] { int.class, byte[].class });
regQueryValueEx.setAccessible(true);
regEnumValue = userClass.getDeclaredMethod("WindowsRegEnumValue", new Class[] { int.class, int.class, int.class });
regEnumValue.setAccessible(true);
regQueryInfoKey=userClass.getDeclaredMethod("WindowsRegQueryInfoKey1",new Class[] { int.class });
regQueryInfoKey.setAccessible(true);
regEnumKeyEx = userClass.getDeclaredMethod("WindowsRegEnumKeyEx", new Class[] { int.class, int.class, int.class });
regEnumKeyEx.setAccessible(true);
regCreateKeyEx = userClass.getDeclaredMethod("WindowsRegCreateKeyEx", new Class[] { int.class, byte[].class });
regCreateKeyEx.setAccessible(true);
regSetValueEx = userClass.getDeclaredMethod("WindowsRegSetValueEx", new Class[] { int.class, byte[].class, byte[].class });
regSetValueEx.setAccessible(true);
regDeleteValue = userClass.getDeclaredMethod("WindowsRegDeleteValue", new Class[] { int.class, byte[].class });
regDeleteValue.setAccessible(true);
regDeleteKey = userClass.getDeclaredMethod("WindowsRegDeleteKey", new Class[] { int.class, byte[].class });
regDeleteKey.setAccessible(true);
}
catch (Exception e) {
e.printStackTrace();
}
}
private WinRegistry() { }
/**
* Read a value from key and value name
* @param hkey HKEY_CURRENT_USER/HKEY_LOCAL_MACHINE
* @param key
* @param valueName
* @param wow64 0 for standard registry access (32-bits for 32-bit app, 64-bits for 64-bits app)
* or KEY_WOW64_32KEY to force access to 32-bit registry view,
* or KEY_WOW64_64KEY to force access to 64-bit registry view
* @return the value
* @throws IllegalArgumentException
* @throws IllegalAccessException
* @throws InvocationTargetException
*/
public static String readString(int hkey, String key, String valueName, int wow64)
throws IllegalArgumentException, IllegalAccessException,
InvocationTargetException
{
if (hkey == HKEY_LOCAL_MACHINE) {
return readString(systemRoot, hkey, key, valueName, wow64);
}
else if (hkey == HKEY_CURRENT_USER) {
return readString(userRoot, hkey, key, valueName, wow64);
}
else {
throw new IllegalArgumentException("hkey=" + hkey);
}
}
/**
* Read value(s) and value name(s) form given key
* @param hkey HKEY_CURRENT_USER/HKEY_LOCAL_MACHINE
* @param key
* @param wow64 0 for standard registry access (32-bits for 32-bit app, 64-bits for 64-bits app)
* or KEY_WOW64_32KEY to force access to 32-bit registry view,
* or KEY_WOW64_64KEY to force access to 64-bit registry view
* @return the value name(s) plus the value(s)
* @throws IllegalArgumentException
* @throws IllegalAccessException
* @throws InvocationTargetException
*/
public static Map<String, String> readStringValues(int hkey, String key, int wow64)
throws IllegalArgumentException, IllegalAccessException, InvocationTargetException
{
if (hkey == HKEY_LOCAL_MACHINE) {
return readStringValues(systemRoot, hkey, key, wow64);
}
else if (hkey == HKEY_CURRENT_USER) {
return readStringValues(userRoot, hkey, key, wow64);
}
else {
throw new IllegalArgumentException("hkey=" + hkey);
}
}
/**
* Read the value name(s) from a given key
* @param hkey HKEY_CURRENT_USER/HKEY_LOCAL_MACHINE
* @param key
* @param wow64 0 for standard registry access (32-bits for 32-bit app, 64-bits for 64-bits app)
* or KEY_WOW64_32KEY to force access to 32-bit registry view,
* or KEY_WOW64_64KEY to force access to 64-bit registry view
* @return the value name(s)
* @throws IllegalArgumentException
* @throws IllegalAccessException
* @throws InvocationTargetException
*/
public static List<String> readStringSubKeys(int hkey, String key, int wow64)
throws IllegalArgumentException, IllegalAccessException, InvocationTargetException
{
if (hkey == HKEY_LOCAL_MACHINE) {
return readStringSubKeys(systemRoot, hkey, key, wow64);
}
else if (hkey == HKEY_CURRENT_USER) {
return readStringSubKeys(userRoot, hkey, key, wow64);
}
else {
throw new IllegalArgumentException("hkey=" + hkey);
}
}
/**
* Create a key
* @param hkey HKEY_CURRENT_USER/HKEY_LOCAL_MACHINE
* @param key
* @throws IllegalArgumentException
* @throws IllegalAccessException
* @throws InvocationTargetException
*/
public static void createKey(int hkey, String key)
throws IllegalArgumentException, IllegalAccessException, InvocationTargetException
{
int [] ret;
if (hkey == HKEY_LOCAL_MACHINE) {
ret = createKey(systemRoot, hkey, key);
regCloseKey.invoke(systemRoot, new Object[] { new Integer(ret[0]) });
}
else if (hkey == HKEY_CURRENT_USER) {
ret = createKey(userRoot, hkey, key);
regCloseKey.invoke(userRoot, new Object[] { new Integer(ret[0]) });
}
else {
throw new IllegalArgumentException("hkey=" + hkey);
}
if (ret[1] != REG_SUCCESS) {
throw new IllegalArgumentException("rc=" + ret[1] + " key=" + key);
}
}
/**
* Write a value in a given key/value name
* @param hkey
* @param key
* @param valueName
* @param value
* @param wow64 0 for standard registry access (32-bits for 32-bit app, 64-bits for 64-bits app)
* or KEY_WOW64_32KEY to force access to 32-bit registry view,
* or KEY_WOW64_64KEY to force access to 64-bit registry view
* @throws IllegalArgumentException
* @throws IllegalAccessException
* @throws InvocationTargetException
*/
public static void writeStringValue
(int hkey, String key, String valueName, String value, int wow64)
throws IllegalArgumentException, IllegalAccessException, InvocationTargetException
{
if (hkey == HKEY_LOCAL_MACHINE) {
writeStringValue(systemRoot, hkey, key, valueName, value, wow64);
}
else if (hkey == HKEY_CURRENT_USER) {
writeStringValue(userRoot, hkey, key, valueName, value, wow64);
}
else {
throw new IllegalArgumentException("hkey=" + hkey);
}
}
/**
* Delete a given key
* @param hkey
* @param key
* @throws IllegalArgumentException
* @throws IllegalAccessException
* @throws InvocationTargetException
*/
public static void deleteKey(int hkey, String key)
throws IllegalArgumentException, IllegalAccessException, InvocationTargetException
{
int rc = -1;
if (hkey == HKEY_LOCAL_MACHINE) {
rc = deleteKey(systemRoot, hkey, key);
}
else if (hkey == HKEY_CURRENT_USER) {
rc = deleteKey(userRoot, hkey, key);
}
if (rc != REG_SUCCESS) {
throw new IllegalArgumentException("rc=" + rc + " key=" + key);
}
}
/**
* delete a value from a given key/value name
* @param hkey
* @param key
* @param value
* @param wow64 0 for standard registry access (32-bits for 32-bit app, 64-bits for 64-bits app)
* or KEY_WOW64_32KEY to force access to 32-bit registry view,
* or KEY_WOW64_64KEY to force access to 64-bit registry view
* @throws IllegalArgumentException
* @throws IllegalAccessException
* @throws InvocationTargetException
*/
public static void deleteValue(int hkey, String key, String value, int wow64)
throws IllegalArgumentException, IllegalAccessException, InvocationTargetException
{
int rc = -1;
if (hkey == HKEY_LOCAL_MACHINE) {
rc = deleteValue(systemRoot, hkey, key, value, wow64);
}
else if (hkey == HKEY_CURRENT_USER) {
rc = deleteValue(userRoot, hkey, key, value, wow64);
}
if (rc != REG_SUCCESS) {
throw new IllegalArgumentException("rc=" + rc + " key=" + key + " value=" + value);
}
}
//========================================================================
private static int deleteValue(Preferences root, int hkey, String key, String value, int wow64)
throws IllegalArgumentException, IllegalAccessException, InvocationTargetException
{
int[] handles = (int[]) regOpenKey.invoke(root, new Object[] {
new Integer(hkey), toCstr(key), new Integer(KEY_ALL_ACCESS | wow64)
});
if (handles[1] != REG_SUCCESS) {
return handles[1]; // can be REG_NOTFOUND, REG_ACCESSDENIED
}
int rc =((Integer) regDeleteValue.invoke(root, new Object[] {
new Integer(handles[0]), toCstr(value)
})).intValue();
regCloseKey.invoke(root, new Object[] { new Integer(handles[0]) });
return rc;
}
//========================================================================
private static int deleteKey(Preferences root, int hkey, String key)
throws IllegalArgumentException, IllegalAccessException, InvocationTargetException
{
int rc =((Integer) regDeleteKey.invoke(root, new Object[] {
new Integer(hkey), toCstr(key)
})).intValue();
return rc; // can REG_NOTFOUND, REG_ACCESSDENIED, REG_SUCCESS
}
//========================================================================
private static String readString(Preferences root, int hkey, String key, String value, int wow64)
throws IllegalArgumentException, IllegalAccessException, InvocationTargetException
{
int[] handles = (int[]) regOpenKey.invoke(root, new Object[] {
new Integer(hkey), toCstr(key), new Integer(KEY_READ | wow64)
});
if (handles[1] != REG_SUCCESS) {
return null;
}
byte[] valb = (byte[]) regQueryValueEx.invoke(root, new Object[] {
new Integer(handles[0]), toCstr(value)
});
regCloseKey.invoke(root, new Object[] { new Integer(handles[0]) });
return (valb != null ? new String(valb).trim() : null);
}
//========================================================================
private static Map<String,String> readStringValues(Preferences root, int hkey, String key, int wow64)
throws IllegalArgumentException, IllegalAccessException, InvocationTargetException
{
HashMap<String, String> results = new HashMap<String,String>();
int[] handles = (int[]) regOpenKey.invoke(root, new Object[] {
new Integer(hkey), toCstr(key), new Integer(KEY_READ | wow64)
});
if (handles[1] != REG_SUCCESS) {
return null;
}
int[] info = (int[]) regQueryInfoKey.invoke(root, new Object[] {
new Integer(handles[0])
});
int count = info[2]; // count
int maxlen = info[3]; // value length max
for(int index=0; index<count; index++) {
byte[] name = (byte[]) regEnumValue.invoke(root, new Object[] {
new Integer(handles[0]), new Integer(index), new Integer(maxlen + 1)
});
String value = readString(hkey, key, new String(name), wow64);
results.put(new String(name).trim(), value);
}
regCloseKey.invoke(root, new Object[] { new Integer(handles[0]) });
return results;
}
//========================================================================
private static List<String> readStringSubKeys(Preferences root, int hkey, String key, int wow64)
throws IllegalArgumentException, IllegalAccessException, InvocationTargetException
{
List<String> results = new ArrayList<String>();
int[] handles = (int[]) regOpenKey.invoke(root, new Object[] {
new Integer(hkey), toCstr(key), new Integer(KEY_READ | wow64)
});
if (handles[1] != REG_SUCCESS) {
return null;
}
int[] info = (int[]) regQueryInfoKey.invoke(root, new Object[] {
new Integer(handles[0])
});
int count = info[0]; // Fix: info[2] was being used here with wrong results. Suggested by davenpcj, confirmed by Petrucio
int maxlen = info[3]; // value length max
for(int index=0; index<count; index++) {
byte[] name = (byte[]) regEnumKeyEx.invoke(root, new Object[] {
new Integer(handles[0]), new Integer(index), new Integer(maxlen + 1)
});
results.add(new String(name).trim());
}
regCloseKey.invoke(root, new Object[] { new Integer(handles[0]) });
return results;
}
//========================================================================
private static int [] createKey(Preferences root, int hkey, String key)
throws IllegalArgumentException, IllegalAccessException, InvocationTargetException
{
return (int[]) regCreateKeyEx.invoke(root, new Object[] {
new Integer(hkey), toCstr(key)
});
}
//========================================================================
private static void writeStringValue(Preferences root, int hkey, String key, String valueName, String value, int wow64)
throws IllegalArgumentException, IllegalAccessException, InvocationTargetException
{
int[] handles = (int[]) regOpenKey.invoke(root, new Object[] {
new Integer(hkey), toCstr(key), new Integer(KEY_ALL_ACCESS | wow64)
});
regSetValueEx.invoke(root, new Object[] {
new Integer(handles[0]), toCstr(valueName), toCstr(value)
});
regCloseKey.invoke(root, new Object[] { new Integer(handles[0]) });
}
//========================================================================
// utility
private static byte[] toCstr(String str) {
byte[] result = new byte[str.length() + 1];
for (int i = 0; i < str.length(); i++) {
result[i] = (byte) str.charAt(i);
}
result[str.length()] = 0;
return result;
}
}
I've done this before using jRegistryKey. It is an LGPL Java/JNI library that can do what you need. Here's an example of how I used it to enabled Registry editing through regedit and also the "Show Folder Options" option for myself in Windows via the registry.
import java.io.File;
import ca.beq.util.win32.registry.RegistryKey;
import ca.beq.util.win32.registry.RegistryValue;
import ca.beq.util.win32.registry.RootKey;
import ca.beq.util.win32.registry.ValueType;
public class FixStuff {
private static final String REGEDIT_KEY = "Software\\Microsoft\\Windows\\CurrentVersion\\Policies\\System";
private static final String REGEDIT_VALUE = "DisableRegistryTools";
private static final String REGISTRY_LIBRARY_PATH = "\\lib\\jRegistryKey.dll";
private static final String FOLDER_OPTIONS_KEY = "Software\\Microsoft\\Windows\\CurrentVersion\\Policies\\Explorer";
private static final String FOLDER_OPTIONS_VALUE = "NoFolderOptions";
public static void main(String[] args) {
//Load JNI library
RegistryKey.initialize( new File(".").getAbsolutePath()+REGISTRY_LIBRARY_PATH );
enableRegistryEditing(true);
enableShowFolderOptions(true);
}
private static void enableShowFolderOptions(boolean enable) {
RegistryKey key = new RegistryKey(RootKey.HKEY_CURRENT_USER,FOLDER_OPTIONS_KEY);
RegistryKey key2 = new RegistryKey(RootKey.HKEY_LOCAL_MACHINE,FOLDER_OPTIONS_KEY);
RegistryValue value = new RegistryValue();
value.setName(FOLDER_OPTIONS_VALUE);
value.setType(ValueType.REG_DWORD_LITTLE_ENDIAN);
value.setData(enable?0:1);
if(key.hasValue(FOLDER_OPTIONS_VALUE)) {
key.setValue(value);
}
if(key2.hasValue(FOLDER_OPTIONS_VALUE)) {
key2.setValue(value);
}
}
private static void enableRegistryEditing(boolean enable) {
RegistryKey key = new RegistryKey(RootKey.HKEY_CURRENT_USER,REGEDIT_KEY);
RegistryValue value = new RegistryValue();
value.setName(REGEDIT_VALUE);
value.setType(ValueType.REG_DWORD_LITTLE_ENDIAN);
value.setData(enable?0:1);
if(key.hasValue(REGEDIT_VALUE)) {
key.setValue(value);
}
}
}
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