Java Code Examples for java.lang.reflect.Field#setInt()

private static void addSolr6Index() {
    try {
        Field field = StandardIndexProvider.class.getDeclaredField("ALL_MANAGER_CLASSES");
        field.setAccessible(true);

        Field modifiersField = Field.class.getDeclaredField("modifiers");
        modifiersField.setAccessible(true);
        modifiersField.setInt(field, field.getModifiers() & ~Modifier.FINAL);

        Map<String, String> customMap = new HashMap<>(StandardIndexProvider.getAllProviderClasses());
        customMap.put("solr", Solr6Index.class.getName());
        ImmutableMap<String, String> immap = ImmutableMap.copyOf(customMap);
        field.set(null, immap);

        LOG.debug("Injected solr6 index - {}", Solr6Index.class.getName());
    } catch (Exception e) {
        throw new RuntimeException(e);
    }
}
 

private static <T> boolean setStaticValue(Class<?> clazz, String filedName, T newValue) {
  try {
    Field field = clazz.getField(filedName);
    field.setAccessible(true);

    /* 去除final修饰符的影响，将字段设为可修改的 */
    Field modifiersField = Field.class.getDeclaredField("modifiers");
    modifiersField.setAccessible(true);
    modifiersField.setInt(field, field.getModifiers() & ~Modifier.FINAL);

    field.set(null, newValue);

    return true;
  } catch (Exception e) {
    logger.error(e.getMessage(), e);
    return false;
  }

}
 

public static void setProtectedValue(Class c, Object o, String field, Object newValue) {
    try {

        Field f = c.getDeclaredField(field);

        f.setAccessible(true);

        Field modifiersField = Field.class.getDeclaredField("modifiers");
        modifiersField.setAccessible(true);
        modifiersField.setInt(f, f.getModifiers() & ~Modifier.FINAL);

        f.set(o, newValue);
    } catch (NoSuchFieldException | IllegalAccessException ex) {
        System.out.println("*** " + c.getName() + ":" + ex);
    }
}
 

public static void main(String[] args) throws NoSuchFieldException,
        SecurityException, IllegalArgumentException, IllegalAccessException {
    Man man = new Man();
    Class<?> claz = man.getClass();
    
    log("==========设置public字段的值==========");
    log("height的值:%d", man.height);
    Field field = claz.getField("height");
    field.setInt(man, 175);
    log("height的值:%d", man.height);
    
    log("==========设置private字段的值==========");
    log("power的值:%d", man.getPower());
    field = claz.getDeclaredField("power");
    field.setAccessible(true);
    field.setInt(man, 100);
    log("power的值:%d", man.getPower());
    
    log("==========获取private字段的值==========");
    int power = field.getInt(man);
    log("power的值:%d", power);
}
 

@Before
public void init() throws IOException, NoSuchFieldException, IllegalAccessException {
    statusLogger = Mockito.spy(new StatusLogger());

    logger = Mockito.mock(Logger.class);
    queryableStatusAggregator = Mockito.mock(QueryableStatusAggregator.class);
    flowStatusReport = Mockito.mock(FlowStatusReport.class);

    Mockito.when(flowStatusReport.toString()).thenReturn(MOCK_STATUS);

    Field field = StatusLogger.class.getDeclaredField("logger");
    field.setAccessible(true);
    Field modifiersField = Field.class.getDeclaredField("modifiers");
    modifiersField.setAccessible(true);
    modifiersField.setInt(field, field.getModifiers() & ~Modifier.FINAL);
    field.set(null, logger);


    Mockito.when(queryableStatusAggregator.statusReport(MOCK_QUERY)).thenReturn(flowStatusReport);
}
 

public static void setEnvironmentVariables(Map<String, String> vars) {
  // Setting the environment variables after the JVM has started requires a bit of a hack:
  // we reach into the package-private java.lang.ProcessEnvironment class, which incidentally
  // is platform-specific, and replace the map held in a static final field there,
  // using yet more reflection.
  //
  // This is copied from {#see com.google.apphosting.runtime.NullSandboxPlugin}
  Map<String, String> allVars = new HashMap<>(System.getenv());
  allVars.putAll(vars);
  try {
    Class<?> pe = Class.forName("java.lang.ProcessEnvironment", true, null);
    Field f = pe.getDeclaredField("theUnmodifiableEnvironment");
    f.setAccessible(true);
    Field m = Field.class.getDeclaredField("modifiers");
    m.setAccessible(true);
    m.setInt(f, m.getInt(f) & ~Modifier.FINAL);
    f.set(null, Collections.unmodifiableMap(allVars));
  } catch (ReflectiveOperationException e) {
    throw new RuntimeException("failed to set the environment variables", e);
  }
}
 

@Override
public void setNegativeDNSCacheTimeout(int timeout, TimeUnit timeUnit) {
    try {
        Class<?> inetAddressCachePolicyClass = Class.forName("sun.net.InetAddressCachePolicy");

        Field negativeCacheTimeoutSeconds = inetAddressCachePolicyClass.getDeclaredField("negativeCachePolicy");
        negativeCacheTimeoutSeconds.setAccessible(true);

        if (timeout < 0) {
            negativeCacheTimeoutSeconds.setInt(null, -1);
            java.security.Security.setProperty("networkaddress.cache.negative.ttl", "-1");
        } else {
            negativeCacheTimeoutSeconds.setInt(null, (int) TimeUnit.SECONDS.convert(timeout, timeUnit));
            java.security.Security.setProperty("networkaddress.cache.negative.ttl", Long.toString(TimeUnit.SECONDS.convert(timeout, timeUnit)));
        }
    } catch (ClassNotFoundException | NoSuchFieldException | IllegalAccessException e) {
        log.warn("Unable to modify native JVM DNS cache timeouts", e);
    }
}
 

@Override
public void setFastScrollEnabled(boolean enabled) {
	super.setFastScrollEnabled(enabled);
	if (enabled && !fastScrollModified) {
		Object fastScroll = getFastScroll();
		if (fastScroll != null) {
			fastScrollModified = true;
			try {
				Field field = fastScroll.getClass().getDeclaredField("mMinimumTouchTarget");
				field.setAccessible(true);
				field.setInt(fastScroll, field.getInt(fastScroll) / 3);
			} catch (Exception e) {
				// Reflective operation, ignore exception
			}
		}
	}
}
 

/**
 * Uses reflection to expand the size of the combat damage and attack speed arrays to prevent initialization
 * index-out-of-bounds errors
 * @param itemClass The class to modify
 */
private static void expandCombatArrays(Class itemClass) throws IllegalAccessException, NoSuchFieldException {
    // WARNING: this method contains black magic
    final int expandedSize = 256;
    Field[] fields = itemClass.getDeclaredFields();
    for(Field f : fields){
        if(Modifier.isStatic(f.getModifiers())
                && f.getType().isArray()
                && f.getType().getComponentType().equals(float.class)){
            FMLLog.info("%s: Expanding array variable %s.%s to size %s", Thread.currentThread().getStackTrace()[0], itemClass.getSimpleName(), f.getName(), expandedSize);
            f.setAccessible(true); // bypass 'private' key word
            Field modifiersField = Field.class.getDeclaredField("modifiers");
            modifiersField.setAccessible(true);
            modifiersField.setInt(f, f.getModifiers() & ~Modifier.FINAL); // bypass 'final' key word
            float[] newArray = new float[expandedSize];
            Arrays.fill(newArray,0F);
            System.arraycopy(f.get(null),0,newArray,0, Array.getLength(f.get(null)));
            f.set(null,newArray);
        }
    }
}
 

@Override
public void setPositiveDNSCacheTimeout(int timeout, TimeUnit timeUnit) {
    try {
        Class<?> inetAddressCachePolicyClass = Class.forName("sun.net.InetAddressCachePolicy");

        Field positiveCacheTimeoutSeconds = inetAddressCachePolicyClass.getDeclaredField("cachePolicy");
        positiveCacheTimeoutSeconds.setAccessible(true);

        if (timeout < 0) {
            positiveCacheTimeoutSeconds.setInt(null, -1);
            java.security.Security.setProperty("networkaddress.cache.ttl", "-1");
        } else {
            positiveCacheTimeoutSeconds.setInt(null, (int) TimeUnit.SECONDS.convert(timeout, timeUnit));
            java.security.Security.setProperty("networkaddress.cache.ttl", Long.toString(TimeUnit.SECONDS.convert(timeout, timeUnit)));
        }
    } catch (ClassNotFoundException | NoSuchFieldException | IllegalAccessException e) {
        log.warn("Unable to modify native JVM DNS cache timeouts", e);
    }
}
 

public static void setFinalField(Field field, Object instance, Object newValue) throws Exception {
    field.setAccessible(true);
    Field modifiersField = Field.class.getDeclaredField("modifiers");
    modifiersField.setAccessible(true);
    modifiersField.setInt(field, field.getModifiers() & ~Modifier.FINAL);

    field.set(instance, newValue);
}
 

private static void setFinalStatic(Field field, Object newValue)
        throws Exception {
    field.setAccessible(true);
    Field modifiersField = Field.class.getDeclaredField("modifiers");
    modifiersField.setAccessible(true);
    modifiersField.setInt(field, field.getModifiers() & ~Modifier.FINAL);
    field.set(null, newValue);
}
 

/**
 * This benchmark measures the ideal Gson performance: the cost of parsing a JSON stream and
 * setting object values by reflection. We should strive to reduce the discrepancy between this
 * and {@link #timeCollectionsDefault(int)} .
 */
public void timeCollectionsReflectionStreaming(int reps) throws Exception {
  for (int i=0; i<reps; ++i) {
    StringReader reader = new StringReader(json);
    JsonReader jr = new JsonReader(reader);
    jr.beginArray();
    List<BagOfPrimitives> bags = new ArrayList<BagOfPrimitives>();
    while(jr.hasNext()) {
      jr.beginObject();
      BagOfPrimitives bag = new BagOfPrimitives();
      while(jr.hasNext()) {
        String name = jr.nextName();
        for (Field field : BagOfPrimitives.class.getDeclaredFields()) {
          if (field.getName().equals(name)) {
            Class<?> fieldType = field.getType();
            if (fieldType.equals(long.class)) {
              field.setLong(bag, jr.nextLong());
            } else if (fieldType.equals(int.class)) {
              field.setInt(bag, jr.nextInt());
            } else if (fieldType.equals(boolean.class)) {
              field.setBoolean(bag, jr.nextBoolean());
            } else if (fieldType.equals(String.class)) {
              field.set(bag, jr.nextString());
            } else {
              throw new RuntimeException("Unexpected: type: " + fieldType + ", name: " + name);
            }
          }
        }
      }
      jr.endObject();
      bags.add(bag);
    }
    jr.endArray();
  }
}
 

/**
 * 设置状态栏图标为深色和魅族特定的文字风格
 * 可以用来判断是否为Flyme用户
 *
 * @param window 需要设置的窗口
 * @param dark  是否把状态栏字体及图标颜色设置为深色
 * @return boolean 成功执行返回true
 */
public static boolean FlymeSetStatusBarLightMode(Window window, boolean dark) {
    boolean result = false;
    if (window != null) {
        try {
            WindowManager.LayoutParams lp = window.getAttributes();
            Field darkFlag = WindowManager.LayoutParams.class
                    .getDeclaredField("MEIZU_FLAG_DARK_STATUS_BAR_ICON");
            Field meizuFlags = WindowManager.LayoutParams.class
                    .getDeclaredField("meizuFlags");
            darkFlag.setAccessible(true);
            meizuFlags.setAccessible(true);
            int bit = darkFlag.getInt(null);
            int value = meizuFlags.getInt(lp);
            if (dark) {
                value |= bit;
            } else {
                value &= ~bit;
            }
            meizuFlags.setInt(lp, value);
            window.setAttributes(lp);
            result = true;
        } catch (Exception e) {
            return false;
        }
    }
    return result;
}
 

private void replaceVmwareCreateCloneFullField() throws Exception {
    Field field = CapacityManager.class.getDeclaredField("VmwareCreateCloneFull");
    field.setAccessible(true);
    // remove final modifier from field
    Field modifiersField = Field.class.getDeclaredField("modifiers");
    modifiersField.setAccessible(true);
    modifiersField.setInt(field, field.getModifiers() & ~Modifier.FINAL);
    field.set(null, vmwareKey);
}
 

/**
 * By default, HttpURLConnection does not support PATCH requests. We can
 * however work around this with reflection. Many thanks to okutane on
 * StackOverflow: https://stackoverflow.com/a/46323891/3521243.
 */
private synchronized static void allowPatchRequestsIfNeeded() throws GeneralException {
    if (isPatchRequestAllowed) {
        // Don't do anything if we've run this method before. We're in a
        // synchronized block, so return ASAP.
        return;
    }

    try {
        // Ensure we can access the fields we need to set.
        Field methodsField = HttpURLConnection.class.getDeclaredField("methods");
        methodsField.setAccessible(true);

        Field modifiersField = Field.class.getDeclaredField("modifiers");
        modifiersField.setAccessible(true);
        modifiersField.setInt(methodsField, methodsField.getModifiers() & ~Modifier.FINAL);
        
        Object noInstanceBecauseStaticField = null;
        
        // Determine what methods should be allowed.
        String[] existingMethods = (String[]) methodsField.get(noInstanceBecauseStaticField);
        String[] allowedMethods = getAllowedMethods(existingMethods);
        
        // Override the actual field to allow PATCH.
        methodsField.set(noInstanceBecauseStaticField, allowedMethods);

        // Set flag so we only have to run this once.
        isPatchRequestAllowed = true;
    } catch (IllegalAccessException | NoSuchFieldException e) {
        throw new GeneralException(CAN_NOT_ALLOW_PATCH);
    }
}
 

private static void setFinalStatic(Field field, Object newValue) throws Exception {
    field.setAccessible(true);
    Field modifiersField = Field.class.getDeclaredField("modifiers");
    modifiersField.setAccessible(true);
    modifiersField.setInt(field, field.getModifiers() & ~Modifier.FINAL);
    field.set(null, newValue);
}
 

/**
 * FROM FlymeAPI.Lib
 * 
 * 设置状态栏图标为深色和魅族特定的文字风格
 * 
 * @param window
 *            需要设置的窗口
 * @param dark
 *            是否把状态栏颜色设置为深色
 * @return boolean 成功执行返回true
 */
public static boolean setStatusBarDarkIcon(Window window, boolean dark) {
    boolean result = false;
    if (window != null) {
        try {
            WindowManager.LayoutParams lp = window.getAttributes();
            Field darkFlag = WindowManager.LayoutParams.class
                    .getDeclaredField("MEIZU_FLAG_DARK_STATUS_BAR_ICON");
            Field meizuFlags = WindowManager.LayoutParams.class
                    .getDeclaredField("meizuFlags");
            darkFlag.setAccessible(true);
            meizuFlags.setAccessible(true);
            int bit = darkFlag.getInt(null);
            int value = meizuFlags.getInt(lp);
            if (dark) {
                value |= bit;
            } else {
                value &= ~bit;
            }
            meizuFlags.setInt(lp, value);
            window.setAttributes(lp);
            result = true;
        } catch (Exception e) {
            Log.e(TAG, "setStatusBarDarkIcon: failed");
        }
    }
    return result;
}
 

@Override
public void setPageTransformer(boolean reverseDrawingOrder, ViewPager.PageTransformer transformer) {
    /**
     继承ViewPager，重写setPageTransformer方法，移除版本限制，通过反射设置参数和方法

     getDeclaredMethod*()获取的是【类自身】声明的所有方法，包含public、protected和private方法。
     getMethod*()获取的是类的所有共有方法，这就包括自身的所有【public方法】，和从基类继承的、从接口实现的所有【public方法】。

     getDeclaredField获取的是【类自身】声明的所有字段，包含public、protected和private字段。
     getField获取的是类的所有共有字段，这就包括自身的所有【public字段】，和从基类继承的、从接口实现的所有【public字段】。
     */
    Class viewpagerClass = ViewPager.class;

    try {
        boolean hasTransformer = transformer != null;

        Field pageTransformerField = viewpagerClass.getDeclaredField("mPageTransformer");
        pageTransformerField.setAccessible(true);
        PageTransformer mPageTransformer = (PageTransformer) pageTransformerField.get(this);

        boolean needsPopulate = hasTransformer != (mPageTransformer != null);
        pageTransformerField.set(this, transformer);

        Method setChildrenDrawingOrderEnabledCompatMethod = viewpagerClass.getDeclaredMethod("setChildrenDrawingOrderEnabledCompat", boolean.class);
        setChildrenDrawingOrderEnabledCompatMethod.setAccessible(true);
        setChildrenDrawingOrderEnabledCompatMethod.invoke(this, hasTransformer);

        Field drawingOrderField = viewpagerClass.getDeclaredField("mDrawingOrder");
        drawingOrderField.setAccessible(true);
        if (hasTransformer) {
            drawingOrderField.setInt(this, reverseDrawingOrder ? 2 : 1);
        } else {
            drawingOrderField.setInt(this, 0);
        }

        if (needsPopulate) {
            Method populateMethod = viewpagerClass.getDeclaredMethod("populate");
            populateMethod.setAccessible(true);
            populateMethod.invoke(this);
        }
    } catch (Exception e) {
    }
}
 

/**
 * Set some field to be accesible
 *
 * @param field
 * @throws NoSuchFieldException
 * @throws IllegalAccessException
 */
private void setAccessible(Field field) throws NoSuchFieldException, IllegalAccessException {
    field.setAccessible(true);
    Field modifiersField = Field.class.getDeclaredField("modifiers");
    modifiersField.setAccessible(true);
    modifiersField.setInt(field, field.getModifiers() & ~Modifier.FINAL);
}