1.先看看效果图吧：
打印的日志：
/com.example.administrator.testz E/TAG: getCrashFilePath: /storage/emulated/0/Testz/Crash/
2.写入文件当然需要先添加权限
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
3.开始写byte数组
package com.example.administrator.testz;
import android.annotation.SuppressLint;
import android.content.Context;
import android.os.Environment;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import java.util.Locale;
public class MainActivity extends AppCompatActivity {
private static final String CRASH_REPORTER_EXTENSION = ".txt";
private Button btn;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btn = (Button) findViewById(R.id.btn_write);
btn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
try {
writeBytesToFile();
} catch (IOException e) {
e.printStackTrace();
}
}
});
}
public void writeBytesToFile() throws IOException {
StringBuilder sb = new StringBuilder();
@SuppressLint("SimpleDateFormat") SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss", Locale.CHINA);
String now = sdf.format(new Date());
sb.append("TIME:").append(now);
String s = "69 00 01 03 AA 16";
byte[] bs = s.getBytes();
OutputStream out = new FileOutputStream(getCrashFilePath(MainActivity.this) + now + CRASH_REPORTER_EXTENSION);
InputStream is = new ByteArrayInputStream(bs);
byte[] buff = new byte[1024];
int len = 0;
while ((len = is.read(buff)) != -1) {
out.write(buff, 0, len);
}
is.close();
out.close();
}
/**
* 获取文件夹路径
*
* @param context
* @return
*/
private static String getCrashFilePath(Context context) {
String path = null;
try {
path = Environment.getExternalStorageDirectory().getCanonicalPath() + "/"
+ context.getResources().getString(R.string.app_name) + "/Crash/";
File file = new File(path);
if (!file.exists()) {
file.mkdirs();
}
} catch (IOException e) {
e.printStackTrace();
}
Log.e("TAG", "getCrashFilePath: " + path);
return path;
}
}
注意保存文件，要做动态权限申请
2.把byte转成16进制的数据，在存，大家以后碰到类似的需求时，一定要学会灵活应用
package com.example.administrator.testz;
import android.annotation.SuppressLint;
import android.content.Context;
import android.os.Environment;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import java.io.BufferedInputStream;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.UnsupportedEncodingException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import java.util.Locale;
public class MainActivity extends AppCompatActivity {
private static final String CRASH_REPORTER_EXTENSION = ".txt";
private Button btn;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btn = (Button) findViewById(R.id.btn_write);
btn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
try {
writeBytesToFile();
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/**
* 字节数组转成16进制表示格式的字符串
*
* @param byteArray 需要转换的字节数组
* @return 16进制表示格式的字符串
**/
public static String toHexString(byte[] byteArray) {
if (byteArray == null || byteArray.length < 1)
throw new IllegalArgumentException("this byteArray must not be null or empty");
final StringBuilder hexString = new StringBuilder();
for (int i = 0; i < byteArray.length; i++) {
if ((byteArray[i] & 0xff) < 0x10)//0~F前面不零
hexString.append("0");
hexString.append(Integer.toHexString(0xFF & byteArray[i]));
}
return hexString.toString().toLowerCase();
}
public void writeBytesToFile() throws IOException {
StringBuilder sb = new StringBuilder();
@SuppressLint("SimpleDateFormat") SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss", Locale.CHINA);
String now = sdf.format(new Date());
sb.append("TIME:").append(now);
byte[] datas = new byte[]{0x69, 0x01, 0x05, 0x03, 0x65, 0x16};
byte[] bs = toHexString(datas).getBytes();
OutputStream out = new FileOutputStream(getCrashFilePath(MainActivity.this) + now + CRASH_REPORTER_EXTENSION);
InputStream is = new ByteArrayInputStream(bs);
byte[] buff = new byte[1024];
int len = 0;
while ((len = is.read(buff)) != -1) {
out.write(buff, 0, len);
}
is.close();
out.close();
}
/**
* 获取文件夹路径
* @param context
* @return
*/
private static String getCrashFilePath(Context context) {
String path = null;
try {
path = Environment.getExternalStorageDirectory().getCanonicalPath() + "/"
+ context.getResources().getString(R.string.app_name) + "/Crash/";
File file = new File(path);
if (!file.exists()) {
file.mkdirs();
}
} catch (IOException e) {
e.printStackTrace();
}
Log.e("TAG", "getCrashFilePath: " + path);
return path;
}
}
