http断点续传简单实现（java)

/* })Ix.!p  
**SiteFileFetch.java t;bZc s  
*/ ajg7xF{l)  
package NetFox; |rG8E;>  
import java.io.*; UzP@{?  
import java.net.*; :"h Pg]'  
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public class SiteFileFetch extends Thread { w;g)Iy6x  
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SiteInfoBean siteInfoBean = null; //文件信息Bean HQjxJd5P  
long[] nStartPos; //开始位置 (Qw`%B  
long[] nEndPos; //结束位置 ~QQEHx\4zZ  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 50O7=  
long nFileLength; //文件长度 ([z<TS#Md  
boolean bFirst = true; //是否第一次取文件 H"kc^G+(R"  
boolean bStop = false; //停止标志 O#<|[Dzw  
File tmpFile; //文件下载的临时信息 _oYA;O  
DataOutputStream output; //输出到文件的输出流 +Px<DX+  
LL6ON }
 
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） )4VLm  
public SiteFileFetch(SiteInfoBean bean) throws IOException [U_Q 2<H  
{ 4IH0
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siteInfoBean = bean; 0Te)s3X  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); q|de*~@-P  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); x(T!I&i={  
if(tmpFile.exists ()) T/X?ZK(T  
{ I3F6-gH  
bFirst = false; 6jQ&dN{=qB  
read_nPos(); ;+#za?w  
} M,=@
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else {g23[$X]N  
{ I{Y {
  
nStartPos = new long[bean.getNSplitter()]; kM}ic(K  
nEndPos = new long[bean.getNSplitter()]; Z:r$;`K/  
} oqQ?2k<@  
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} EusfgU:  
),W(TL  
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public void run() (PE8H~d  
{ d[qEP6B  
//获得文件长度 %s&E-*X  
//分割文件 &,6y(-  
//实例FileSplitterFetch t8a@L(J$  
//启动FileSplitterFetch线程 UH.}B3H  
//等待子线程返回 xhp-4  
try{ SFXfo1dqH  
if(bFirst) [f0oB$  
{ )e <! =S  
nFileLength = getFileSize(); r5fz6"  
if(nFileLength == -1) :p*ojl|  
{ dcc%G7w  
System.err.println("File Length is not known!"); >(1_Dn\  
} ^~*[~  
else if(nFileLength == -2) OL6xMToP  
{ Xk$l-Zfse  
System.err.println("File is not access!"); g}s-v?+  
} IJb1) ZuR  
else CzDR%vx  
{ V+@%(x@D_  
for(int i=0;i<nStartPos.length;i++) EY[
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{ Bb2r95h}^  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); aZ`_W|  
} olQ8s*  
for(int i=0;i<nEndPos.length-1;i++) AD4L`0D  
{  6@Z'fT4  
nEndPos = nStartPos[i+1]; s5Bmv\e.i5  
} 4jyr\=42F'  
nEndPos[nEndPos.length-1] = nFileLength; W;)FNP|MT  
} E]U3O>hf  
} +
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cM7k){  
~jCpL@rS  
//启动子线程 8BoT%kVeJv  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 6XxG1]84  
for(int i=0;i<nStartPos.length;i++) h1UlLy8  
{ KE)D =P  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 3I{ta/(  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 1\.zOq#  
nStartPos,nEndPos,i); P.H/H04+  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); TF iM[  
fileSplitterFetch.start(); &s}@7htE  
} %
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), <:yq~?  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 6^z\;,p  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", i[BR(D&l_p  
nEndPos = " + nFileLength); _XO)`D~  
// fileSplitterFetch[nPos.length-1].start(); ?M{6U[?  
{J6sM$aj  
^TCJh^4na  
//等待子线程结束 j[=_1~u}  
//int count = 0; y:6'&`L  
//是否结束while循环 _)Z7Le:f!  
boolean breakWhile = false; 1b]PCNz  
;h(;(  
.0*CT:1=0  
while(!bStop) GPqB\bxb'  
{ A(@gv8e[H^  
write_nPos(); UEYM;$_@4o  
Utility.sleep(500); <[B[  
breakWhile = true; =rO>b{,hs  
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{@F["YPxy  
for(int i=0;i<nStartPos.length;i++) 8iH;GFNJ7'  
{ L)nVpqm   
if(!fileSplitterFetch.bDownOver) BnnUUaE  
{ q?]@' ^:;  
breakWhile = false; <W[8k-yOV`  
break; sq6%=(q(?  
} Sph"w08  
} o_KcnVQ\  
if(breakWhile) -O>mY)  
break; mP .&fS  
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j{w,<Wt>  
//count++; Wv*BwiQ  
//if(count>4) $^D(%  
// siteStop(); (>5VS  
}  yLIj4bf  
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po
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System.err.println("文件下载结束！"); 4l!Yop0h  
} Y l3[~S  
catch(Exception e){e.printStackTrace ();} LsD9hb7  
} ]!
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{
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//获得文件长度 xW;[}t-QS  
public long getFileSize() G~hILW^  
{ > FcA,  
int nFileLength = -1; wj5s5dH  
try{ T]Td4T!  
URL url = new URL(siteInfoBean.getSSiteURL()); qsRfG~Cg  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); "91Atb;hJ  
httpConnection.setRequestProperty("User-Agent","NetFox"); pz6- hi7  
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int responseCode=httpConnection.getResponseCode(); eHyuO)(xH1  
if(responseCode>=400) ]4Yb$e`  
{ V5@[7ncVf  
processErrorCode(responseCode); ue:P#] tx  
return -2; //-2 represent access is error vKOn7  
} 6{r[Dq  
+PXfr~ 4  
86 /i~s  
String sHeader; ieLN;)Iy^  
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for(int i=1;;i++) E=~WQ13Q  
{ 4k?JxA)  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); `lh?Z3W  
//Utility.log(in.readLine()); K]*ERAfM%m  
sHeader=httpConnection.getHeaderFieldKey(i); !J(,M)p!  
if(sHeader!=null) LuQ M$/i  
{ bme#G
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if(sHeader.equals("Content-Length")) <21^{ yt1  
{ `*9FKs  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); *_rGB
W  
break; M~Dc5\T  
} 0Lz56e'j  
} Q/`o6xv  
else 1xV1#'@[Jd  
break; ef;="N  
} m]}"FMH$  
} 19{?w6G<k  
catch(IOException e){e.printStackTrace ();} b/}0 &VXo  
catch(Exception e){e.printStackTrace ();} &r%^wfp  
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Utility.log(nFileLength); ^X'7>{7Io  
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return nFileLength; _7HJ'  
}  ^52R`{  
)g^Ewzy^X  
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//保存下载信息（文件指针位置） M@[gT?mv1  
private void write_nPos() ]@T `qR  
{ X1qj l_A  
try{ N^`Efpvg  
output = new DataOutputStream(new FileOutputStream(tmpFile)); cDyC&}:f  
output.writeInt(nStartPos.length); J|8YB3K,  
for(int i=0;i<nStartPos.length;i++) y'wW2U/1-  
{ KCT"a:\  
// output.writeLong(nPos); +Z(VWu6  
output.writeLong(fileSplitterFetch.nStartPos);  #X_M  
output.writeLong(fileSplitterFetch.nEndPos); {v/6|  
} <rmV$_  
output.close(); @<JQn^M  
} :2gO) 'cD  
catch(IOException e){e.printStackTrace ();} ]-LE'Px|  
catch(Exception e){e.printStackTrace ();} 5)i0g  
} I T2sS6&R  
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n:
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//读取保存的下载信息（文件指针位置） {X"]92+  
private void read_nPos() dg8
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{ w~?eX/;  
try{ bdhgHjz  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); .
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int nCount = input.readInt(); z{WqICnb  
nStartPos = new long[nCount]; ToM*tXj  
nEndPos = new long[nCount]; 640V&<+v  
for(int i=0;i<nStartPos.length;i++) TBYL~QQD\C  
{ L(S.  
nStartPos = input.readLong(); F
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nEndPos = input.readLong(); ZWEzL$VWi  
} ub&29Qte  
input.close(); [6N39G$  
} gcF><i6  
catch(IOException e){e.printStackTrace ();} bZfJG^3  
catch(Exception e){e.printStackTrace ();} w2AWdO6  
} @eU/g![u  
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private void processErrorCode(int nErrorCode) >(a_9l;q  
{ IvH+94[)  
System.err.println("Error Code : " + nErrorCode); 6E4L4Vb  
} F\<i>LWT'  
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xc3Q7u!|  
//停止文件下载 ^Tmmx_Xw  
public void siteStop() NebZGD2K  
{ v0H#\p  
bStop = true; b7mP~]V  
for(int i=0;i<nStartPos.length;i++) _?<Fc8F  
fileSplitterFetch.splitterStop(); Vd~k4  
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 /9Xf[<  
} <0}'#9>O  
} i[J',  
//负责部分文件的抓取 MLX.MUS  
**FileSplitterFetch.java Lq^/Z4L  
*/ <'33!8 G  
package NetFox; (FHh,y~v  
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import java.io.*; ^;bkU|(`6  
import java.net.*; ]f?LQCTq<b  

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public class FileSplitterFetch extends Thread { ]=Q'1%  
0kfw8Lon  
_i#Z'4?2E  
String sURL; //File URL 50A_+f.7%  
long nStartPos; //File Snippet Start Position 0Jr<>7Q1  
long nEndPos; //File Snippet End Position X)+N>8o?N  
int nThreadID; //Thread's ID fCR;Fk2B  
boolean bDownOver = false; //Downing is over i`;
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boolean bStop = false; //Stop identical duCm+4,.  
FileAccessI fileAccessI = null; //File Access interface :1Cc~+]w(u  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException {[+gM?  
{ LtBH4A  
this.sURL = sURL; HS7!
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this.nStartPos = nStart; EC0auB7G  
this.nEndPos = nEnd; +FR"Gt$g  
nThreadID = id; Kkm7L-  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 I(e
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} ';%g^!lM a  
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public void run() [(mq8Nb  
{ $nW>]S\|  
while(nStartPos < nEndPos && !bStop) /e\dsC{uJ  
{ y:L|]p}huE  
zoU.\]#C  
57r)&8  
try{ "7DPsPs  
URL url = new URL(sURL); [B[J%?NS  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); "O`;zC  
httpConnection.setRequestProperty("User-Agent","NetFox"); ?W(f%/B#  
String sProperty = "bytes="+nStartPos+"-"; yLP0w^Q  
httpConnection.setRequestProperty("RANGE",sProperty); EMo6$(  
Utility.log(sProperty); "M tQj}  
>
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InputStream input = httpConnection.getInputStream(); %j,Ny}a  
//logResponseHead(httpConnection); 7blZAA?-  
='FEC-f95  
x?kZD~|{)  
byte[] b = new byte[1024]; uH#NJoRO  
int nRead; = N#Ww
NC  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 3^\y>
 
{ Y'P8`$  
nStartPos += fileAccessI.write(b,0,nRead); g6farLBF  
//if(nThreadID == 1) S.z;Bm  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);  7)T+!>  
} ,Xw/ t>  
m`|Z1CT  
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Utility.log("Thread " + nThreadID + " is over!"); *=8)]_=f  
bDownOver = true; +2?[=g4;}  
//nPos = fileAccessI.write (b,0,nRead); 4R]|  
} >h9U~#G=  
catch(Exception e){e.printStackTrace ();} tv0xfAV  
} g 0L 4  
} UpITx]y?"m  
\?o%<c5{  
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//打印回应的头信息 ;WhB2/5v  
public void logResponseHead(HttpURLConnection con) x[X.// :  
{ D7@10;F}[  
for(int i=1;;i++) ^V:YNUqp#  
{ &Fi8@0Fh  
String header=con.getHeaderFieldKey(i); La!PGZ{  
if(header!=null) p4[W@JV  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 5^xt/vYa)  
Utility.log(header+" : "+con.getHeaderField(header)); 5FMKJ7sC9  
else 8|l Yf%n>j  
break; H`
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} L81"W`?  
} O Rfl v+  
75F&s,4+  
3"".kf,O5e  
public void splitterStop() HOw hl  
{ _eF*8 /z  
bStop = true; Rm RV8 WJ6  
} ;ry{cq  
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@6E[K'5c1  
} %[0"[<1a  
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/* jC oZm(bi  
**FileAccess.java M;E&@[5  
*//文件访问(定位，写) I9MI}0}7  
package NetFox; sOJ~PRA  
import java.io.*; t!k 0n&P  
9we=aX5  
29GiNy+ob  
public class FileAccessI implements Serializable{ m4iR '~L}  
]mc,FlhU@  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 B5cTzY.h-  
RandomAccessFile oSavedFile; ,R)[$n  
long nPos; OJ 2M_q)e  
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public FileAccessI() throws IOException 4 (yHD  
{ {hl_/ aG  
this("",0); qGw6Wp~  
} suVS!} C  
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public FileAccessI(String sName,long nPos) throws IOException vw3W:TL  
{ 2|cIu 'U  
oSavedFile = new RandomAccessFile(sName,"rw"); >
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this.nPos = nPos; *-n$n  
oSavedFile.seek(nPos); [`&cA#C9Yp  
} >A)he!I  
ua{eri[  
Ze~\=X" "  
public synchronized int write(byte[] b,int nStart,int nLen) E )PEKWK\  
{ ^O?$}sr  
int n = -1; 5t PmrWZ  
try{ $&4Zw6"=  
oSavedFile.write(b,nStart,nLen); U!Lws#\X  
n = nLen; j04Q3d \f  
} e#AB0-f  
catch(IOException e) qj|GAGrQ2  
{ q\~7z1   
e.printStackTrace (); LP87X-qkjW  
} 9=/8d`r  
>?kt3.IQ!X  
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return n; JmBYD[h,  
} *)w 8fq  
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} u/MIB`@,  
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/* &O'yhAP] j  
**SiteInfoBean.java iCHZ{<k  
*/ #*~ (  
package NetFox; .1}u0IbJ  
\!%3giD5!  
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public class SiteInfoBean { QCjmg5bf'7  
CN >q`[!  
4jXyA/F9V  
private String sSiteURL; //Site's URL FPqgncBHK  
private String sFilePath; //Saved File's Path [-%oO  
private String sFileName; //Saved File's Name :S%|^QAN  
private int nSplitter; //Count of Splited Downloading File UeVF@rw  
1 4|S^UM$  
ZHZ>YSqCS  
public SiteInfoBean() )JjfPb64  
{//nSplitter的缺省值为5 z`BRz&  
//default value of nSplitter is 5 %=|I;kI?  
this("","","",5); XnNK)dUT}  
} P}PSS#nn  
I5e!vCG)  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ]s<Q-/X  
{ aH:eu<s  
sSiteURL= sURL; Ji7A9Hk  
sFilePath = sPath; ;[|x5o/<  
sFileName = sName; CocvEoE*z  
this.nSplitter = nSpiltter; E1>3[3  
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gh~C.>W}q+  
} s_]rje8`  
F'"-4YV>&  
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public String getSSiteURL() z*R"917  
{ ?
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return sSiteURL;
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} #3qkG)  
h\yYg'CC  
^EB}e
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public void setSSiteURL(String value) 5tf/VT   
{ m7eO T  
sSiteURL = value; O[N{&\$  
} Sw0~6RZ  
m.2  
u!F3Rh8D  
public String getSFilePath() wwF20  
{ tvg7mU]l  
return sFilePath; Yu8WmX,[  
} "BTA"  
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public void setSFilePath(String value) F6fm{  
{ F'Wef11Yz  
sFilePath = value; {}.c.W+  
} T$+}Srb  
Z,
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7`P(LQAr!  
public String getSFileName() &)wQ|{P~k  
{ I5-/KVWb  
return sFileName; C[[z3tn  
} q-uYfXZ{j  
6#.R'O  
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public void setSFileName(String value) jx-W$@  
{ K%Rx5 
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sFileName = value; ' rXkTm1{  
} r^]0LJ  
&^z~wJ,]  
G;tIhq[$Vb  
public int getNSplitter() YAO.Ccz  
{ 44n^21k  
return nSplitter; t4,6`d?C  
} V57^0^Zp`  
MRiETd"  
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public void setNSplitter(int nCount) Q:%gJ6pa  
{ <8H`y(S  
nSplitter = nCount; [jafPi(#g  
} c|I{U[(U  
} xOS4J+'s@  
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/* |vGz 1jLV  
**Utility.java D F0~A  
*/ VNPuOU=  
package NetFox; d/|@"z^?  
] Li(E:  
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public class Utility { 51L:%Af  
}B"kJNxV  
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public Utility() g6nB
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{ mvYr"6f8  
}J:~}?^%n  
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} 96 C|R  
n#m )]YQC  
//线程睡眠 b`1P%OjC  
public static void sleep(int nSecond) {y :/9  
{ +]B^*99  
try{ YKj7~yK?  
Thread.sleep(nSecond); 4,uH 4[7  
}
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catch(Exception e) PF4Cs3m/  
{ "&7v.-Yk(  
e.printStackTrace (); pnVtjWrbG  
}
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} Rg'1 F  
/EWF0XV!  
//日志 #O
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public static void log(String sMsg) 1!,lI?j,  
{ HSyohP87  
System.err.println(sMsg); 84|Hn|4t  
} y_\vXY'  
Rh~<#"G]  
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public static void log(int sMsg) tZ4W]od  
{ )PR{ia64;<  
System.err.println(sMsg); Z1*y$=D?3[  
} E5.)ro=$  
} /J1O{L  
*"4 OXyV  
;Q-(tGd  
/* (%\N-[yZ  
**TestMethod.java eBG7]u,
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*/ 2v yB[(  
package NetFox; iv\?TAZC  
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[O9(sWL'  
public class TestMethod { )7:2v1Xr]  
nB"q   
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public TestMethod() %Wn/)#T|  
{ ///xx/weblogic60b2_win.exe ~E#>2Mh  
try{ 9fyk7~V  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Fj-mo>"  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); <?QY\wyikz  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 6]7iiQz"H  
fileFetch.start(); .#Z}}W#  
} ^D"}OQoh  
catch(Exception e){e.printStackTrace ();} ;,4Z5+  
mJ[LmQ<:  
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} Spt[b.4mF  
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_qM'm^z5  
public static void main(String[] args) N%n#
mV;  
{ if r!ha+8!  
new TestMethod(); Nmns3D  
} R7( + ^%  
} lB.P   
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