技术标签： Android JSON文件解析 java OTA Android
mainActivity :
package com.example.he.toby.otademo; import android.content.pm.PackageInfo; import android.content.pm.PackageManager; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.util.Log; import android.view.View; import android.widget.Button; import android.widget.TextView; import android.widget.Toast; public class MainActivity extends AppCompatActivity { private TextView textView; private Button SerxmlOta; private Button downLoadJar; Update manager; private static final int DOWNLOAD = 1; private static final int DOWNLOAD_FINISH = 2; private String tag = getClass().getSimpleName(); private static final String MJAR_TEST = "http://192.168.11.39:8080/Uiauto-Jar/first.txt"; Update update ; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); this.textView = (TextView) findViewById(R.id.textView); update = new Update(MainActivity.this); // TODO: 2016/5/20 findViewById(R.id.button).setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { UpdateManger mUpdatemanger = new UpdateManger(MainActivity.this); mUpdatemanger.checkUpdateInfo(); Toast.makeText(getApplicationContext(), "调用updatemanger类", Toast.LENGTH_SHORT).show(); } }); // TODO: 2016/5/20 版本 findViewById(R.id.button2).setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { String versionName = getVersionName(); int versionCode = getVersionCode(); Toast.makeText(getApplicationContext(), "VersionName-->" + versionName + "\n" + "VersionCode-->" + versionCode, Toast.LENGTH_SHORT).show(); textView.setText("APP版本:" + "\nVersionName-->" + versionName + "\n" + "VersionCode-->" + versionCode); Log.e("MainActivity", "VersionName-->" + versionName+","+"VersionCode-->" + versionCode); } }); // TODO: 2016/5/20 serxml解析 this.SerxmlOta = (Button) findViewById(R.id.button3); SerxmlOta.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { Toast.makeText(getApplicationContext(), "serxml 解析更新xml文件", Toast.LENGTH_SHORT).show(); update.checkUpdate(); } }); // TODO: 2016/5/20 download JAR findViewById(R.id._dlj).setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { Log.e(tag, "down load jar "); update.resultJson(); } }); } private String getVersionName() { String versionname; try { PackageManager packageManager = getPackageManager(); PackageInfo packageInfo = packageManager.getPackageInfo(this.getPackageName(), 0); versionname = packageInfo.versionName; } catch (PackageManager.NameNotFoundException e) { e.printStackTrace(); versionname = null; } return versionname; } private int getVersionCode() { Log.e(tag, "当前的版本调用"); int versionCode; try { PackageManager packageManager = getPackageManager(); PackageInfo packageInfo = packageManager.getPackageInfo(this.getPackageName(), 0); versionCode = packageInfo.versionCode; } catch (PackageManager.NameNotFoundException e) { e.printStackTrace(); versionCode = -1; } return versionCode; } }
UpdateManger类
package com.example.he.toby.otademo; import android.annotation.SuppressLint; import android.app.Dialog; import android.content.Context; import android.content.DialogInterface; import android.content.Intent; import android.content.pm.PackageInfo; import android.content.pm.PackageManager; import android.net.Uri; import android.os.Environment; import android.os.Handler; import android.os.Message; import android.util.Log; import android.view.LayoutInflater; import android.view.View; import android.widget.ProgressBar; import android.widget.Toast; import java.io.File; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.net.HttpURLConnection; import java.net.MalformedURLException; import java.net.URL; import java.util.HashMap; /** * Created by toby.he on 2016/3/17. */ public class UpdateManger { // 应用程序Context private Context mContext; // 提示消息 private String updateMsg = "有最新的软件包，请下载！"; // 下载安装包的网络路径 private String apkUrl = "http://192.168.11.39:8080/Tracer/GigasetTracers1.0.apk"; private Dialog noticeDialog;// 提示有软件更新的对话框 private Dialog downloadDialog;// 下载对话框 private static final String savePath = Environment.getExternalStorageDirectory().toString()+File.separator; // 保存apk的文件夹 private static final String saveFileName = savePath + "UpdateDemoRelease.apk"; // 进度条与通知UI刷新的handler和msg常量 private ProgressBar mProgress; private static final int DOWN_UPDATE = 1; private static final int DOWN_OVER = 2; private int progress;// 当前进度 private Thread downLoadThread; // 下载线程 private boolean interceptFlag = false;// 用户取消下载 private String TAG = getClass().getSimpleName(); HashMap<String, String> mHashMap; // 通知处理刷新界面的handler private Handler mHandler = new Handler() { @SuppressLint("HandlerLeak") @Override public void handleMessage(Message msg) { switch (msg.what) { case DOWN_UPDATE: mProgress.setProgress(progress); break; case DOWN_OVER: installApk(); break; } super.handleMessage(msg); } }; public UpdateManger(Context context) { this.mContext = context; } // 显示更新程序对话框，供主程序调用 public void checkUpdateInfo() { // if (isUpdate()) { showNoticeDialog(); // } // else { // Toast.makeText(mContext, "不更新", Toast.LENGTH_LONG).show(); // } } private int getVersionCode(Context context) { int versionCode = 0; try { versionCode = context.getPackageManager().getPackageInfo("com.example.he.toby.otademo", 0).versionCode; } catch (PackageManager.NameNotFoundException e) { e.printStackTrace(); } return versionCode; } private boolean isUpdate() { { int versionCode = getVersionCode(mContext); //本地的XML更新 // InputStream inStream = ParseXmlService.class // // .getResourceAsStream("version.xml"); // InputStream inStream = ParseXmlService.class // .getClassLoader() // .getResourceAsStream( // "version1.xml"); //解析网络xml进行更新软件 URL url = null; try { url = new URL("http://192.168.11.39:8080/Tracer/ServerVersion.xml"); Log.e(TAG, "down load "); } catch (MalformedURLException e1) { // TODO Auto-generated catch block e1.printStackTrace(); } HttpURLConnection conn = null; try { conn = (HttpURLConnection)url.openConnection(); } catch (IOException e1) { // TODO Auto-generated catch block e1.printStackTrace(); } conn.setConnectTimeout(5000); InputStream is = null; try { is = conn.getInputStream(); } catch (IOException e1) { // TODO Auto-generated catch block e1.printStackTrace(); } ParseXmlService service = new ParseXmlService(); try { mHashMap = service .parseXml(is); } catch (Exception e) { e.printStackTrace(); } if (null != mHashMap) { int serviceCode = Integer.valueOf(mHashMap.get("version")); if (serviceCode > versionCode) { Log.e(TAG,"当前版本是version-->"+versionCode+"\n服务server版本是-->"+serviceCode); return true; } } return false; } } private void showNoticeDialog() { android.app.AlertDialog.Builder builder = new android.app.AlertDialog.Builder( mContext);// Builder，可以通过此builder设置改变AleartDialog的默认的主题样式及属性相关信息 builder.setTitle("软件版本更新"); builder.setMessage(updateMsg); builder.setPositiveButton("下载", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { dialog.dismiss();// 当取消对话框后进行操作一定的代码？取消对话框 showDownloadDialog(); } }); Log.e("shownoticeD","show noticedialog"); builder.setNegativeButton("以后再说", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { dialog.dismiss(); } }); noticeDialog = builder.create(); noticeDialog.show(); } protected void showDownloadDialog() { android.app.AlertDialog.Builder builder = new android.app.AlertDialog.Builder(mContext); builder.setTitle("软件版本更新"); final LayoutInflater inflater = LayoutInflater.from(mContext); View v = inflater.inflate(R.layout.progress, null); mProgress = (ProgressBar) v.findViewById(R.id.progress); builder.setView(v);// 设置对话框的内容为一个View builder.setNegativeButton("取消", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { dialog.dismiss(); interceptFlag = true; } }); downloadDialog = builder.create(); downloadDialog.show(); downloadApk(); } private void downloadApk() { downLoadThread = new Thread(mdownApkRunnable); downLoadThread.start(); } protected void installApk() { File apkfile = new File(saveFileName); if (!apkfile.exists()) { return; } Intent i = new Intent(Intent.ACTION_VIEW); i.setDataAndType(Uri.parse("file://" + apkfile.toString()), "application/vnd.android.package-archive");// File.toString()会返回路径信息 mContext.startActivity(i); } private Runnable mdownApkRunnable = new Runnable() { @Override public void run() { URL url; try { url = new URL(apkUrl); HttpURLConnection conn = (HttpURLConnection) url.openConnection(); conn.connect(); int length = conn.getContentLength(); conn.setConnectTimeout(5000); InputStream ins = conn.getInputStream(); File file = new File(savePath); if (!file.exists()) { file.mkdir(); } String apkFile = saveFileName; File ApkFile = new File(apkFile); FileOutputStream outStream = new FileOutputStream(ApkFile); int count = 0; byte buf[] = new byte[1024]; do { int numread = ins.read(buf); count += numread; progress = (int) (((float) count / length) * 100); // 下载进度 mHandler.sendEmptyMessage(DOWN_UPDATE); if (numread <= 0) { // 下载完成通知安装 mHandler.sendEmptyMessage(DOWN_OVER); break; } outStream.write(buf, 0, numread); } while (!interceptFlag);// 点击取消停止下载 outStream.close(); ins.close(); } catch (Exception e) { e.printStackTrace(); } } }; }
Update 类
package com.example.he.toby.otademo; import android.app.AlertDialog; import android.app.AlertDialog.Builder; import android.app.Dialog; import android.content.ContentValues; import android.content.Context; import android.content.DialogInterface; import android.content.Intent; import android.content.pm.PackageManager; import android.net.Uri; import android.os.Environment; import android.os.Handler; import android.os.Message; import android.util.Log; import android.view.LayoutInflater; import android.view.View; import android.widget.ProgressBar; import android.widget.Toast; import com.android.volley.RequestQueue; import com.android.volley.Response; import com.android.volley.VolleyError; import com.android.volley.toolbox.JsonObjectRequest; import com.android.volley.toolbox.Volley; import org.json.JSONArray; import org.json.JSONException; import org.json.JSONObject; import java.io.ByteArrayOutputStream; import java.io.File; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.net.HttpURLConnection; import java.net.MalformedURLException; import java.net.URL; import java.util.ArrayList; import java.util.HashMap; import java.util.Iterator; import java.util.Map; /** * Created by toby.he on 2016/3/22. */ public class Update { private static final int DOWNLOAD_ING = 1; private static final int DOWNLOAD_FINISH = 2; private String TAG = getClass().getSimpleName().toString(); HashMap<String, String> mHashMap; private String mSavePath; private int progress; private boolean cancelUpdate = false; private Context mContext; private ProgressBar mProgress; private Dialog mDownloadDialog; private static final String PATH = "http://192.168.11.39:8080/Tracer/ServerVersion.html"; private String mVersion_code; private String mVersion_name; private String mVersion_desc; private String mVersion_path; // TODO: 2016/4/12 jar文件地址 private String mJar_name; private String mJar_url; public static final String MJAR_PATH = "http://192.168.11.39:8080/Uiauto-Jar/test.html"; String[] nameList=null ; // 通知处理刷新界面的handler private Handler mHandler = new Handler() { public void handleMessage(Message msg) { switch (msg.what) { case DOWNLOAD_ING: mProgress.setProgress(progress); break; case DOWNLOAD_FINISH: // 隐藏当前下载对话框 mDownloadDialog.dismiss(); //安装APK installApk(); break; default: break; } } }; // TODO: 2016/4/12 获取版本 private Handler mGetVersion = new Handler() { public void handleMessage(Message msg) { JSONObject jsonObject = (JSONObject) msg.obj; System.out.println(jsonObject.toString()); try { mVersion_code = jsonObject.getString("version_code"); mVersion_name = jsonObject.getString("version_name"); mVersion_desc = jsonObject.getString("version_desc"); mVersion_path = jsonObject.getString("version_path"); if (isUpdate()) { Toast.makeText(mContext, "需要更新", Toast.LENGTH_SHORT).show(); // 显示提示更新对话框 showNoticeDialog(); } else { Toast.makeText(mContext, "已是最新版本", Toast.LENGTH_SHORT).show(); } } catch (Exception e) { e.printStackTrace(); } } }; public Update(Context context) { this.mContext = context; Log.e(TAG, "update"); } //检查更新 public void checkUpdate() { RequestQueue requestQueue = Volley.newRequestQueue(mContext); JsonObjectRequest request = new JsonObjectRequest(PATH, null, new Response.Listener<JSONObject>() { @Override public void onResponse(JSONObject jsonObject) { Message msg = Message.obtain(); msg.obj = jsonObject; mGetVersion.sendMessage(msg); Log.e(TAG, jsonObject.toString()); } }, new Response.ErrorListener() { @Override public void onErrorResponse(VolleyError volleyError) { Log.e(TAG, volleyError.toString()); } }); requestQueue.add(request); } public static int getLineNumber(Exception e){ StackTraceElement[] trace =e.getStackTrace(); if(trace==null||trace.length==0) return -1; // return trace[0].getLineNumber(); } // TODO: 2016/4/12 检测jar文件 public void checkJar() { try { String result = readParse(mJar_url); Toast.makeText(mContext,"result-->"+result,Toast.LENGTH_SHORT).show(); } catch (Exception e) { e.printStackTrace(); } } Handler mGetJarHandler = new Handler(){ @Override public void handleMessage(Message msg) { super.handleMessage(msg); JSONArray jsonArray = null; ArrayList<HashMap<String, String>> list = new ArrayList<>(); try { jsonArray = new JSONArray(msg.obj); } catch (JSONException e) { e.printStackTrace(); } // JSONObject jsonObject = (JSONObject) msg.obj; // System.out.println(jsonObject.toString()); for (int i = 0 ; i <jsonArray.length();i++) { try { JSONObject jsonObject = jsonArray.getJSONObject(i); } catch (JSONException e) { e.printStackTrace(); } HashMap<String,String> map = new HashMap<String,String>(); map.put("NAME",mJar_name); map.put("URL", mJar_url); list.add(map); } Iterator<HashMap<String, String>> it = list.iterator(); StringBuffer strbf = new StringBuffer(); while (it.hasNext()) { HashMap<String, String> ma = it.next(); // strbf.append(ma.) } } }; // TODO: 2016/4/12 多选对话框 private void MultiChoiceDialog() { AlertDialog.Builder builder = new AlertDialog.Builder(mContext); builder.setIcon(R.mipmap.ic_launcher); builder.setTitle("所有的JAR包"); // final String[] hobbies = {"篮球", "足球", "网球", "斯诺克"}; // 设置一个单项选择下拉框 /** * 第一个参数指定我们要显示的一组下拉多选框的数据集合 * 第二个参数代表哪几个选项被选择，如果是null，则表示一个都不选择，如果希望指定哪一个多选选项框被选择， * 需要传递一个boolean[]数组进去，其长度要和第一个参数的长度相同，例如 {true, false, false, true}; * 第三个参数给每一个多选项绑定一个监听器 */ builder.setMultiChoiceItems(nameList, null, new DialogInterface.OnMultiChoiceClickListener() { StringBuffer sb = new StringBuffer(100); @Override public void onClick(DialogInterface dialog, int which, boolean isChecked) { if(isChecked) { sb.append(nameList[which] + ", "); } // Toast.makeText(mContext, "爱好为：" + sb.toString(), Toast.LENGTH_SHORT).show(); } }); builder.setPositiveButton("确定", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { Log.e(TAG, "sure"); // Toast.makeText(mContext,"这里添加要下载执行",Toast.LENGTH_SHORT).show(); } }); builder.setNegativeButton("取消", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { } }); builder.show(); } /* * 与本地版本比较判断是否需要更新 */ public boolean isUpdate() { int serverVersion = Integer.parseInt(mVersion_code); int localVersion = 1; localVersion = getVersionCode(mContext); if (serverVersion > localVersion) { Log.e(TAG, "当前版本是version-->" + localVersion + "\n服务server版本是-->" + serverVersion); return true; } return false; } private int getVersionCode(Context context) { int versionCode = 0; try { versionCode = context.getPackageManager().getPackageInfo("com.example.he.toby.otademo", 0).versionCode; } catch (PackageManager.NameNotFoundException e) { e.printStackTrace(); } return versionCode; } private void showNoticeDialog() { Log.e(TAG, "showNoticeDialog()"); AlertDialog.Builder builder = new Builder(mContext); builder.setTitle("提示"); String msg = "有软件更新,要下载更新么 ?\n" + mVersion_desc; builder.setMessage(msg); builder.setPositiveButton("UPDATE", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { //隐藏对话框 dialog.dismiss(); //显示下载对话框 showDownloadDialog(); } }); builder.setNegativeButton("Cancle", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { dialog.dismiss(); } }); builder.create().show(); } private void installApk() { File apkfile = new File(mSavePath, mVersion_name); if (!apkfile.exists()) { return; } Intent i = new Intent(Intent.ACTION_VIEW); i.setDataAndType(Uri.parse("file://" + apkfile.toString()), "application/vnd.android.package-archive"); mContext.startActivity(i); } private void showDownloadDialog() { Builder builder = new Builder( mContext); builder.setTitle("更新中"); final LayoutInflater inflater = LayoutInflater.from(mContext); View v = inflater.inflate(R.layout.progress, null); mProgress = (ProgressBar) v.findViewById(R.id.progress); builder.setView(v); builder.setNegativeButton(R.string.soft_update_cancel, new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { dialog.dismiss(); cancelUpdate = true; } }); mDownloadDialog = builder.create(); mDownloadDialog.show(); // TODO: 2016/3/22 下载 downloadApk(); } private void downloadApk() { new downloadApkThread().start(); } private class downloadApkThread extends Thread { @Override public void run() { Log.e(TAG, " Will Downloadapk"); try { if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) { String sdpath = Environment.getExternalStorageDirectory() + "/"; mSavePath = sdpath + "download"; File file = new File(mSavePath); if (!file.exists()) { file.mkdir(); } // TODO: 2016/4/1 下载 HttpURLConnection conn = (HttpURLConnection) new URL(mVersion_path).openConnection(); conn.connect(); int length = conn.getContentLength(); InputStream is = conn.getInputStream(); File apkFile = new File(mSavePath, mVersion_name); FileOutputStream fos = new FileOutputStream(apkFile); int count = 0; byte buf[] = new byte[1024]; do { int numread = is.read(buf); count += numread; progress = (int) (((float) count / length) * 100); // 更新进度条 mHandler.sendEmptyMessage(DOWNLOAD_ING); if (numread < 0) { mHandler.sendEmptyMessage(DOWNLOAD_FINISH); break; } fos.write(buf, 0, numread); } while (!cancelUpdate); fos.close(); is.close(); } } catch (MalformedURLException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } // mDownloadDialog.dismiss(); } } /** * 从指定的URL中获取数组 * @param urlPath * @return * @throws Exception */ public String readParse(String urlPath) throws Exception { ByteArrayOutputStream outStream = new ByteArrayOutputStream(); byte[] data = new byte[1024]; int len = 0; URL url = new URL(urlPath); HttpURLConnection conn = (HttpURLConnection) url.openConnection(); InputStream inStream = conn.getInputStream(); while ((len = inStream.read(data)) != -1) { outStream.write(data, 0, len); } inStream.close(); return new String((outStream.toByteArray()));//通过out.Stream.toByteArray获取到写的数据 } /** * 解析 * * @throws JSONException */ private ArrayList<HashMap<String, Object>> Analysis(String jsonStr) throws JSONException { /******************* 解析 ***********************/ JSONArray jsonArray = null; Log.d(TAG, "后：" + jsonStr); // 初始化list数组对象 ArrayList<HashMap<String, Object>> list = new ArrayList<HashMap<String, Object>>(); //转化成 JSONObject类 JSONObject js = new JSONObject(jsonStr); if (js.has("TestJar")) { jsonArray = js.getJSONArray("TestJar"); if (jsonArray.length()>0) { for (int i = 0; i<jsonArray.length();i++) { JSONObject jsonOj = jsonArray.getJSONObject(i); String NAME = ""; String URL = ""; if(jsonOj.has("NAME")){ NAME = jsonOj.getString("NAME"); } if(jsonOj.has("URL")){ URL = jsonOj.getString("URL"); } // 初始化map数组对象 HashMap<String, Object> map = new HashMap<String, Object>(); map.put("NAME", NAME); map.put("URL", URL); list.add(map); Log.d(TAG, "SearchResultJson>>>" + " NAME=" + NAME + " URL=" + URL); System.out.println("name:" + NAME); } } } // nameList = new String[jsonArray.length()]; return list; } /** * readParse（String）从服务器端获取数据 * Analysis（String）解析json数据 */ ArrayList<HashMap<String, Object>> allData ; String jsonObject = null; public void resultJson() { new Thread(new Runnable() { @Override public void run() { try { jsonObject = readParse(MJAR_PATH); Log.e(TAG, "从服务器中读取到的数据:\n"+jsonObject); allData = Analysis(jsonObject); Iterator<HashMap<String, Object>> it = allData.iterator(); while (it.hasNext()) { Map<String, Object> ma = it.next(); Log.e("name&&url","NAME: "+ma.get("NAME")+",URL:"+ma.get("URL")+"\n"); } // MultiChoiceDialog(); } catch (Exception e) { e.printStackTrace(); } } }).start(); // try { // allData = Analysis(readParse(MJAR_PATH)); } }
xml文件
<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin" android:paddingRight="@dimen/activity_horizontal_margin" android:paddingTop="@dimen/activity_vertical_margin" android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".MainActivity"> <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="UpdateManger_OTA" android:id="@+id/button" android:layout_alignParentTop="true" android:layout_alignParentRight="true" android:layout_alignParentEnd="true" android:layout_alignParentLeft="true" android:layout_alignParentStart="true" /> <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="版本code" android:id="@+id/button2" android:layout_below="@+id/button" android:layout_alignParentLeft="true" android:layout_alignParentStart="true" android:layout_alignRight="@+id/button" android:layout_alignEnd="@+id/button" /> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/textView" android:layout_below="@+id/button2" android:layout_alignParentLeft="true" android:layout_alignParentStart="true" android:layout_alignParentRight="true" android:layout_alignParentEnd="true" /> <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Server-xml解析-OTA" android:id="@+id/button3" android:layout_centerVertical="true" android:layout_alignParentLeft="true" android:layout_alignParentStart="true" android:layout_alignParentRight="true" android:layout_alignParentEnd="true" /> <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="DownLoadJar从服务器上下载" android:id="@+id/_dlj" android:layout_below="@+id/button3" android:layout_alignParentLeft="true" android:layout_alignParentStart="true" android:layout_alignRight="@+id/button3" android:layout_alignEnd="@+id/button3" /> </RelativeLayout>
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comparable和comparator之间的区别Java 中为我们提供了两种比较机制：Comparable 和 Comparator，二者都是用来实现对象的比较、排序。下面分别对Comparable 和 Comparator做具体介绍并总结。Comparable：Comparable可以认为是一个内比较器，实现了Comparable接口的类有一个特点，就是这些类是可以和自己比较的，至于具体和另一个实现了Comparable接口的类如何比较，则依赖compareTo方法的实现。如果add进入一个_请说明使用comparator比使用comparable好在什么地方
Time Limit: 1 Sec Memory Limit:128 MBSubmit: 527 Solved: 282[Submit][Status][Web Board]Description在主函数中输入n(nInputn和n个不等长字符串Outputn个已排好序的字符串Sample Input5abc_问题 f: c语言习题 不等长字符串排序
1)auto 这个关键字用于声明变量的生存期为自动，即将不在任何类、结构、枚举、联合和函数中定义的变量视为全局变量，而在函数中定义的变量视为局部变量。这个关键字不怎么多写，因为所有的变量默认就是auto的。 (2)register 这个关键字命令编译器尽可能的将变量存在CPU内部寄存器中而不是通过内存寻址访问以提高效率。 (3)static 常见的两种用途
统计字符个数C语言程序统计字符个数的C语言程序输入一行字符，分别统计出其中英文字母、空格、数字和其他字符的个数。[题解分析]：统计程序的典型结构：初值归零: int n=0; // n的取名最好与被统计的对象相关。输入数据。计数: 循环事件{ if ( 相关对象出现 ) n++; }输出。//当存在多项统计时，注意输出序列不要混乱。//注解：因为统计是针对输入的，所以输入可以放在循环事件内。..._编写程序统计分析文本,求其中出现的字符种数
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JVM1:如何查看虚拟机是哪个类型cmd命令 查看 java -version 查看本地虚拟机版本，我本机安装的是HotSpot3:特点一次编译，到处运行 自动内存管理 自动垃圾回收机机制 JVM就是二进制字节码的运行环境4: 结构硬件-----windows/linux 操作系统----JVM虚拟机---- 二进制字节码文件-----java文件5:jvm ,jre , jdk, javase , javaee 都是什么jvm 是虚拟机 j...
一、JDBCUtils工具类作用：使代码更加的简洁，更具有逻辑性和复用性。简介：连接数据库的四个参数：驱动类、URL、用户名、密码若要更改连接数据库信息，那么就可以直接在配置文件中修改这四个参数；具体实现代码如下：JdbcUtils.classpackage com.health.JDBC.util;import java.io.FileNotFoundExcept..._jdbcutils.class