android property 怎么单独编译
1. property应用例子
Java:
import Android.os.SystemProperties;
SystemProperties.get(“persist.sys.usb.config“, “mtp,adb“);
SystemProperties.getBoolean(“ro.adb.secure“, false);
SystemProperties.set(“sys.usb.config“, config);
SystemProperties.set需要有system权限，可以这么做
a. 在android.mk中，加上LOCAL_CERTIFICATE :=platform
b. 在AndroidManifest.xml中，加上android:sharedUserId=“android.uid.system“
Native C:
#include 《cutils/properties.h》
LOCAL_SHARED_LIBRARIES := \
libcutils
int property_set(const char *key, const char *value)
int property_get(const char *key, char *value, const char *default_value)
property_set(“service.adb.root“, “1“);
property_get(“ro.debuggable“, value, ““)
2. 设置属性的调用过程
SystemProperties.set in Java
set frameworks/base/core/java/android/os/SystemProperties.java
native_set(key, val)
SystemProperties_set frameworks/base/core/jni/android_os_SystemProperties.cpp
property_set /system/core/libcutils/properties.c
setprop in .rc/.sh file
setprop_main system/core/toolbox/setprop.c
property_set /system/core/libcutils/properties.c
property_set /system/core/libcutils/properties.c
HAVE_LIBC_SYSTEM_PROPERTIES #define HAVE_LIBC_SYSTEM_PROPERTIES 1 in build/core/combo/include/arch/Linux-arm/AndroidConfig.h
__system_property_set bionic/libc/bionic/system_properties.c
send_prop_msg(PROP_MSG_SETPROP)
handle_property_set_onfd(case PROP_MSG_SETPROP) system/core/init/property_service.c
检查权限
if “ctl.“ 开头 handle_control_message() system/core/init/init.c
ctrl.start msg_start() 启动service
ctrl.stop msg_stop() 停止service
ctrl.restart msg_restart() 重启service
else property_set()
如果能找到且以ro开头，就返回-1；能找到且不以ro开头调用 __system_property_update()
如果找不到则调用__system_property_add()
如果是“net.“开头，调用property_set(“net.change“, name)
如果以“persist.“开头，调用write_persistent_property();
property_changed(name, value);
除了“persist.“开头的property，关机后值会消失；以“persist.“开头的会保存在/data/property目录下一文件里，可以看write_persistent_property()
3. 属性的初始值
从下面一些文件可以得到属性的初始值
void start_property_service(void)
{
...
load_properties_from_file(PROP_PATH_SYSTEM_BUILD);
load_properties_from_file(PROP_PATH_SYSTEM_DEFAULT);
load_override_properties();
/* Read persistent properties after all default values have been loaded. */
load_persistent_properties();
...
#define PROP_PATH_RAMDISK_DEFAULT “/default.prop“
#define PROP_PATH_SYSTEM_BUILD “/system/build.prop“
#define PROP_PATH_SYSTEM_DEFAULT “/system/default.prop“
#define PROP_PATH_LOCAL_OVERRIDE “/data/local.prop“
4. 属性的权限
如果是serice, 调用check_control_perms()检查权限,可以看看control_perms
如果是其他属性，调用check_perms()检查权限，可以看看property_perms
5. property_changed() system/core/init/init.c
void property_changed(const char *name, const char *value)
{
if (property_triggers_enabled)
queue_property_triggers(name, value);
}
queue_property_triggers()
action_add_queue_tail(act)
设置完属性后，会调用on property相应的action, 可以看看init.rc
谁给我一个PLSQL Developer 注册码
直接下载绿色版的
密码：myuf
PLSQL Developer 11.0.0.1762 中文绿色注册版(免Oracle11g客户端)
免安装Oracle客户端，绿色无公害。
说明：
1、点击 “启动PLSQL.exe“ 即可免装oracle使用PLSQL 或者 使用qidong.bat启动 ；
2、instantclient_11_2为oracle 11 绿色精简版；
3、设置TNS,用记事本打开配置：instantclient_11_2\tnsnames.ora
qidong.bat内容：
set oracle_home=%~dp0\instantclient_11_2
set TNS_ADMIN=%~dp0\instantclient_11_2
set nls_lang=SIMPLIFIED CHINESE_CHINA.ZHS16GBK
set.GBK
start PLSQLDev.exe
作用：设置临时变量，启动plsql
如何使用Curator监听zookeeper事件变化
掌握zookeeper事件监听机制，非常重要，可以说是跨入了进阶的门槛，只有掌握了如何监听某个节点或路径，我们才能在节点变化后，做一些我们想做的事，包括：
1，配置文件同步
2，主从切换
3，分布式队列
4，分布式锁
5，其他
散仙，在以前的文章里面有写过使用zookeeper原生的api，监听zk节点变化，那么本篇我们就来看下，如何使用curator来完成监听，代码如下：
《pre name=“code“ class=“java“》package com.qin.curator.zk;
import javax.sound.midi.Patch;
import org.apache.curator.RetryPolicy;
import org.apache.curator.framework.CuratorFramework;
import org.apache.curator.framework.CuratorFrameworkFactory;
import org.apache.curator.framework.CuratorFrameworkFactory.Builder;
import org.apache.curator.framework.api.CuratorWatcher;
import org.apache.curator.framework.recipes.cache.NodeCache;
import org.apache.curator.framework.recipes.cache.NodeCacheListener;
import org.apache.curator.framework.recipes.cache.PathChildrenCache;
import org.apache.curator.framework.recipes.cache.PathChildrenCacheEvent;
import org.apache.curator.framework.recipes.cache.PathChildrenCacheListener;
import org.apache.curator.retry.ExponentialBackoffRetry;
import org.apache.curator.utils.ZKPaths;
import org.apache.zookeeper.WatchedEvent;
/**
*
* 使用curator监听zookeeper节点
* @author qindongliang
* **/
public class CuratorWatch {
static CuratorFramework zkclient=null;
static String nameSpace=“php“;
static {
String zkhost=“192.168.46.22:2181“;//zk的host
RetryPolicy rp=new ExponentialBackoffRetry(1000, 3);//重试机制
Builder builder = CuratorFrameworkFactory.builder().connectString(zkhost)
.connectionTimeoutMs(5000)
.sessionTimeoutMs(5000)
.retryPolicy(rp);
builder.namespace(nameSpace);
CuratorFramework zclient = builder.build();
zkclient=zclient;
zkclient.start();// 放在这前面执行
zkclient.newNamespaceAwareEnsurePath(nameSpace);
}
public static void main(String args) throws Exception{
watch();
Thread.sleep(Long.MAX_VALUE);
}
/**
*
* 监听节点变化
*
* */
public static void watch()throws Exception{
PathChildrenCache cache = new PathChildrenCache(zkclient, “/zk“, false);
cache.start();
System.out.println(“监听开始/zk........“);
PathChildrenCacheListener plis=new PathChildrenCacheListener() {
@Override
public void childEvent(CuratorFramework client, PathChildrenCacheEvent event)
throws Exception {
switch ( event.getType() )
{
case CHILD_ADDED:
{
System.out.println(“Node added: “ + ZKPaths.getNodeFromPath(event.getData().getPath()));
break;
}
case CHILD_UPDATED:
{
System.out.println(“Node changed: “ + ZKPaths.getNodeFromPath(event.getData().getPath()));
break;
}
case CHILD_REMOVED:
{
System.out.println(“Node removed: “ + ZKPaths.getNodeFromPath(event.getData().getPath()));
break;
}
}
}
};
//注册监听
cache.getListenable().addListener(plis);
}
}
《/pre》
运行后的控制台打印：
《pre name=“code“ class=“java“》18:33:07.722 [main] INFO o.a.c.f.imps.CuratorFrameworkImpl - Starting
18:33:07.727 [main] DEBUG o.a.curator.CuratorZookeeperClient - Starting
18:33:07.727 [main] DEBUG org.apache.curator.ConnectionState - Starting
18:33:07.727 [main] DEBUG org.apache.curator.ConnectionState - reset
18:33:07.734 [main] INFO org.apache.zookeeper.ZooKeeper - Client environment:zookeeper.version=3.4.6-1569965, built on 02/20/2014 09:09 GMT
18:33:07.734 [main] INFO org.apache.zookeeper.ZooKeeper - Client environment:host.name=QINDONGLIANG.dhgatecn.msf
18:33:07.734 [main] INFO org.apache.zookeeper.ZooKeeper - Client environment:java.version=1.7.0_04
18:33:07.734 [main] INFO org.apache.zookeeper.ZooKeeper - Client environment:java.vendor=Oracle Corporation
18:33:07.734 [main] INFO org.apache.zookeeper.ZooKeeper - Client environment:java.home=D:\Java\jdk1.7.0_04\jre
18:33:07.734 [main] INFO org.apache.zookeeper.ZooKeeper - Client environment:java.class.path=D:\eclipseworkspace2yw\opzk\bin;D:\eclipseworkspace2yw\opzk\lib\curator-client-2.6.0.jar;D:\eclipseworkspace2yw\opzk\lib\curator-examples-2.6.0.jar;D:\eclipseworkspace2yw\opzk\lib\curator-framework-2.6.0.jar;D:\eclipseworkspace2yw\opzk\lib\curator-recipes-2.6.0.jar;D:\eclipseworkspace2yw\opzk\lib\curator-test-2.6.0.jar;D:\eclipseworkspace2yw\opzk\lib\curator-x-discovery-2.6.0.jar;D:\eclipseworkspace2yw\opzk\lib\curator-x-discovery-server-2.6.0.jar;D:\eclipseworkspace2yw\opzk\lib\curator-x-rpc-2.6.0.jar;D:\eclipseworkspace2yw\opzk\lib\log4j-1.2.15.jar;D:\eclipseworkspace2yw\opzk\lib\zookeeper-3.4.5.jar;D:\eclipseworkspace2yw\opzk\lib\commons-io-2.1.jar
-oper
