http断点续传简单实现（java)

/* /8Xd2-  
**SiteFileFetch.java 0\DlzIO  
*/ yq]/r=e!k  
package NetFox; g5>c-i  
import java.io.*; "(NJ{J#A  
import java.net.*; <)4>"SN&^  
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public class SiteFileFetch extends Thread { $>6Kn`UX  
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SiteInfoBean siteInfoBean = null; //文件信息Bean [qHtN.  
long[] nStartPos; //开始位置 NB)$l2<d  
long[] nEndPos; //结束位置 {K ,-fbE  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 *T:gx:Sg/  
long nFileLength; //文件长度 *m.4)2u=  
boolean bFirst = true; //是否第一次取文件 =t!$72g\  
boolean bStop = false; //停止标志 ZD`p$:pT  
File tmpFile; //文件下载的临时信息 RuBL_Vi  
DataOutputStream output; //输出到文件的输出流 7Pp~)Kq=  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） me`|i-   
public SiteFileFetch(SiteInfoBean bean) throws IOException >@
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{ "IMq +  
siteInfoBean = bean; I5H#]U  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ,Z aPY  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ki<4G  
if(tmpFile.exists ()) &O;'?/4 S  
{ %YV3-W8S0  
bFirst = false; m14OPZ<3?-  
read_nPos(); ^QbaMX  
} sA1 XtO<&7  
else 2 i:tPe&  
{ geJO#;  
nStartPos = new long[bean.getNSplitter()]; K
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nEndPos = new long[bean.getNSplitter()]; o)SA^5  
} S<=
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} fF.qQTy;7  
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public void run() l>{+X )  
{ (rB?
@:zN  
//获得文件长度 g'nN#O  
//分割文件 wfY]J
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//实例FileSplitterFetch y_A7CG"^  
//启动FileSplitterFetch线程 NI)q<@ju
 
//等待子线程返回 Zrm!,qs  
try{ rwCjNky!  
if(bFirst) kO'_g1f<[  
{ $]I",ef  
nFileLength = getFileSize(); e(~Y!:Q#O  
if(nFileLength == -1) \h UE,^  
{ YdiXj |k+  
System.err.println("File Length is not known!"); HP G*o  
} g)UYpi?p-}  
else if(nFileLength == -2) ~RIn7/A  
{ 1EcXvT=  
System.err.println("File is not access!"); C$#X6Q!,  
} [>xGynU0  
else M%@=BT  
{ O}cg1Q8p  
for(int i=0;i<nStartPos.length;i++) BzyzOtBp3L  
{ &.`/ln  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); y+K21(z.  
}  EWn\]f|  
for(int i=0;i<nEndPos.length-1;i++) <h<4R Rj  
{ l!9G  
nEndPos = nStartPos[i+1]; ]xf|xs  
} ,.PW qfb  
nEndPos[nEndPos.length-1] = nFileLength; _?J:Z*z?  
} v.pj PBU1  
} }Pf7YuUZZ  
`|
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?>
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//启动子线程 .X(*mmH  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Ii4lwZnz  
for(int i=0;i<nStartPos.length;i++) nd?R|._R  
{ (%^Bp\.02!  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), jm$v0=W9#  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 5p5S_%R$e  
nStartPos,nEndPos,i); 7.DAwx.HYK  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ~n$e  
fileSplitterFetch.start(); f[$9k}.  
} n]]!:jFC  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); -f!oq7U  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", +ziQ]r2g  
nEndPos = " + nFileLength); {8as _  
// fileSplitterFetch[nPos.length-1].start(); i[x;k;m2q  
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//等待子线程结束 .-W_m7&}  
//int count = 0; {Kh u'c  
//是否结束while循环 ecgGl,{  
boolean breakWhile = false; "Ca?liy  
2 - ?  
*q/oS8vavd  
while(!bStop) v\gCgx=%j  
{ -+#g.1UL/  
write_nPos(); )/1,Ogb%_  
Utility.sleep(500); Z-BPC|e  
breakWhile = true; K;}h u(*\]  
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for(int i=0;i<nStartPos.length;i++) v4V|j<R  
{ 8LouCv(>  
if(!fileSplitterFetch.bDownOver) #Kp/AN5YC  
{ oztfr<cUH  
breakWhile = false; /92m5p  
break; |K%nVcR=  
} >kJEa8  
} Z*Qra4GBl]  
if(breakWhile) V/jEMJNks  
break; 5lMm8<v  
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//count++; I8 \Ka=w  
//if(count>4) <Hq|<^_K  
// siteStop(); X(;,-7Jw  
} T;u>]"S  
!pNY`sw}  
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System.err.println("文件下载结束！"); C$1}c[  
} XdDy0e4{%<  
catch(Exception e){e.printStackTrace ();} .CL\``
  
} `Al5(0Q  
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=N9a!ii|  
//获得文件长度 fi2@`37PM  
public long getFileSize() n>Rt9  
{ N:y3tpG  
int nFileLength = -1; 6BJPQdqSl  
try{ LI&+5`  
URL url = new URL(siteInfoBean.getSSiteURL()); o!3-=<^  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); YAIDSZ&l[  
httpConnection.setRequestProperty("User-Agent","NetFox"); :(|;J<R%_  
Ba\l`$%X  
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int responseCode=httpConnection.getResponseCode(); s9wcZO  
if(responseCode>=400) @Ee'nP   
{ hoc$aqP6pp  
processErrorCode(responseCode); <Cvlz^K[  
return -2; //-2 represent access is error ueiXY|  
} Q`Q%;%t  
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String sHeader; A(mU,^  
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for(int i=1;;i++) 0wLu*K5$4E  
{ 8gv\
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); aIv>X@U}  
//Utility.log(in.readLine());
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sHeader=httpConnection.getHeaderFieldKey(i); T #&9|  
if(sHeader!=null) L44/eyrp  
{ 3+<}Hm+  
if(sHeader.equals("Content-Length")) !po8[fz~x  
{ ?Mg&e/^  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ()Z!u%j  
break; 1}C|Javkn  
} /3!
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} `4RraJj>0~  
else @N,EoSb :  
break; IRemF@  
} <|NP!eMsw8  
} 4eym$UWw  
catch(IOException e){e.printStackTrace ();} ?q(7avS9  
catch(Exception e){e.printStackTrace ();} BpL,<r,  
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*v[WJ"8@  
Utility.log(nFileLength); gv}Esps R  
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return nFileLength; 4|uh&4"*@W  
} 6uCa iPV  
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//保存下载信息（文件指针位置） bu[v[U4  
private void write_nPos() kzG mDi  
{ {$,e@nn  
try{ :A\8#]3  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ~a:0Q{>a  
output.writeInt(nStartPos.length); r^
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for(int i=0;i<nStartPos.length;i++) 8,pnm  
{ hBf0kl  
// output.writeLong(nPos); Fu0 dYN  
output.writeLong(fileSplitterFetch.nStartPos); NKD<VMcqw  
output.writeLong(fileSplitterFetch.nEndPos); :?s~,G_*l  
} M-3kF
"  
output.close(); QCFLi n+r  
} %O`e!p  
catch(IOException e){e.printStackTrace ();} #Jv|zf5Z  
catch(Exception e){e.printStackTrace ();} 6f
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} 0Zp) DM  
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//读取保存的下载信息（文件指针位置） 7t7"gl
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private void read_nPos()
)UA};Fus  
{ @vd
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try{ f"zXiUV  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); &v7$*n27  
int nCount = input.readInt(); cXiNO ke&  
nStartPos = new long[nCount]; _5
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nEndPos = new long[nCount]; sK8=PZ\  
for(int i=0;i<nStartPos.length;i++) ]a)o@FI  
{ 7F OG^  
nStartPos = input.readLong(); oa(R,{_*q  
nEndPos = input.readLong(); nqNL[w6{  
} *HFRG)[V  
input.close(); q~
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} CM+Nm(|\,  
catch(IOException e){e.printStackTrace ();} T u>5H`  
catch(Exception e){e.printStackTrace ();} DT`TA#O  
} 5qzFH,  
.}n%gc~A  
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private void processErrorCode(int nErrorCode) 1*\JqCR  
{ XdX1GH*C  
System.err.println("Error Code : " + nErrorCode); fvn`$  
} 0|kkwZVPn  
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=e2|:Ba!  
//停止文件下载 sdF;H[  
public void siteStop() @j
*K|+X"  
{ (3Hz=k_  
bStop = true; u`I&&  
for(int i=0;i<nStartPos.length;i++) ;i*<HNQ  
fileSplitterFetch.splitterStop(); | +osEHC  
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} e&WlJ  
} 6%bZZTP`  
//负责部分文件的抓取 w&yK*nBK  
**FileSplitterFetch.java e
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*/ #=mLQSiQ  
package NetFox; {"T$jV:GB  
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import java.io.*; :.wR*E  
import java.net.*; .J0s_[  
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public class FileSplitterFetch extends Thread { `|maf=SnY5  
{;uOc{~+  
5}S~8  
String sURL; //File URL nBw4YDR!  
long nStartPos; //File Snippet Start Position {~J'J$hn8  
long nEndPos; //File Snippet End Position DX>Yf}  
int nThreadID; //Thread's ID 4D+S\S0bk  
boolean bDownOver = false; //Downing is over d:C|laZHn  
boolean bStop = false; //Stop identical LpCJfQ  
FileAccessI fileAccessI = null; //File Access interface a"7zz]XO2  
~6YTm6o  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException @r7ekyO8)  
{ /Kcp9Qx  
this.sURL = sURL; P2la/jN  
this.nStartPos = nStart; bMe/jQuL.$  
this.nEndPos = nEnd; f793yCiG  
nThreadID = id; zh8\ _>+  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 +9LIpU&5  
} je_:hDr  
= BcKWC  
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public void run() jSi\/(E  
{ W:5uoO]=<  
while(nStartPos < nEndPos && !bStop) UnTnc6Bo7W  
{ @ sLb=vb  
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try{ 9
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URL url = new URL(sURL); :wWPEhK  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); u={A4A#  
httpConnection.setRequestProperty("User-Agent","NetFox"); \!`k:lusa  
String sProperty = "bytes="+nStartPos+"-"; @8\7H'K"\  
httpConnection.setRequestProperty("RANGE",sProperty); X#v6v)c  
Utility.log(sProperty); v_U+wga  
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InputStream input = httpConnection.getInputStream(); )W,tL*9[  
//logResponseHead(httpConnection); ZC7ZlL_  
0iS"V^aH  
;t6)(d4z?  
byte[] b = new byte[1024]; }EJAC*W,  
int nRead; s=KK
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) M3m)uiz  
{ b}&2j3-n,  
nStartPos += fileAccessI.write(b,0,nRead); 8d|/^U.w~V  
//if(nThreadID == 1) DIAHIV<  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); LVHIQ9  
} Q[rmsk2L'  
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Utility.log("Thread " + nThreadID + " is over!"); Y\7WCaSgi  
bDownOver = true; LIah'6qR  
//nPos = fileAccessI.write (b,0,nRead); ;@
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} XC*!=h*  
catch(Exception e){e.printStackTrace ();} _8QHx;}  
} U5[,UrC  
} %Z.!T  
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mFk6a{+YX  
//打印回应的头信息 "UM*(&  
public void logResponseHead(HttpURLConnection con) YRU1^=v  
{ @m`1Vq?O  
for(int i=1;;i++) :t)<$dtf[  
{ ]h3{MTr/  
String header=con.getHeaderFieldKey(i); 3'*}ZDC  
if(header!=null) $M:Ru@Du2  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 0,{tBo  
Utility.log(header+" : "+con.getHeaderField(header)); "pA24Ze  
else yb/v?q?Fk  
break; TyGsSc  
} %f-Uwq&}Y"  
} {zNFp#z  
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public void splitterStop() zn+5pn&?  
{ rl__3q  
bStop = true; ;o#wK>pk%M  
} .&Ik(792Z&  
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} ,qUOPW?=  
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/* 'uBagd>*  
**FileAccess.java W{!Slf  
*//文件访问(定位，写) 5Sh.4A\  
package NetFox; %^qf0d*  
import java.io.*; m[w 8|[  
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public class FileAccessI implements Serializable{ )O:T\{7+  
#cCR\$-~  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 <jz\U7TBf  
RandomAccessFile oSavedFile; be+]kp  
long nPos; b0:5i<"w6  
{Gi:W/jJ  
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public FileAccessI() throws IOException w8KVs\/  
{ nW"ml$  
this("",0); sry`EkS  
} Om,M8!E  
5^0K5R6GQf  
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public FileAccessI(String sName,long nPos) throws IOException #Zq[.9!q{  
{ \X]  
oSavedFile = new RandomAccessFile(sName,"rw"); yv+DM`0  
this.nPos = nPos; b&g`AnYT  
oSavedFile.seek(nPos); kN8?.V%Utw  
} x7!YA>  
m&I5~kD  
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public synchronized int write(byte[] b,int nStart,int nLen) /4{.J=R}  
{ -;s-*$I  
int n = -1; ^2<nn op  
try{ R![)B97^  
oSavedFile.write(b,nStart,nLen); V|T3blG?D  
n = nLen; uc?`,;8{`  
} {!av3Pz\  
catch(IOException e) =JDa[_lpN  
{ sqjv3=
}  
e.printStackTrace (); ,0fYB*jk  
} :/6gGU>pu  
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return n; =5D@~?W ZG  
} Z.{r%W{2  
"v[?`<53^l  
|$QL>{81  
} r4wnfy  
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/* hcJny  
**SiteInfoBean.java RI0+9YJ  
*/ noSBwP|v*  
package NetFox; bqI| wGCA"  
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F qH@iZ  
public class SiteInfoBean { FZJyqqA$_  
YA'_Ba(v)  
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private String sSiteURL; //Site's URL 6u-aV  
private String sFilePath; //Saved File's Path YThFskRoO  
private String sFileName; //Saved File's Name @K}8zMmW#  
private int nSplitter; //Count of Splited Downloading File S/)J<?<b  
;=oGg%@aP  
dq U.2~9  
public SiteInfoBean() *JmU",X  
{//nSplitter的缺省值为5 <Q%:c4N  
//default value of nSplitter is 5 GTBT0$9g.  
this("","","",5); _>)=c<HL  
} -7\6j#;l  
;DN:AgXP  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) n?z^"vv$i  
{ AfOq?V  
sSiteURL= sURL; u*C"d1v=  
sFilePath = sPath; C~([aH@-I  
sFileName = sName; ab-MEN`5  
this.nSplitter = nSpiltter; sXmo.{Ayb  
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} YkqauyV^  
@Tl!A1y?  
D
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public String getSSiteURL() |0A:
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{ z,#3YC{'  
return sSiteURL; Me|+)}'p5h  
} twA2
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_  
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public void setSSiteURL(String value) 4 fxD$%9  
{ ?=lnYDj  
sSiteURL = value; ;N/=)
m  
} !s:v UY58  
H%:u9DlEK/  
<(<19t5.  
public String getSFilePath() 6opubI<  
{ <0hJo=6a8  
return sFilePath; uY5Gn.Y  
} S.kFs{;1x  
/^>yDGT,0  
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public void setSFilePath(String value) raPUx_$PH  
{ 9&t!U+  
sFilePath = value; ;"@FLq(n  
} bk#t+tuk  

}hjJt,m  
8*V8B=q}K  
public String getSFileName() u
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{ l8_TeO  
return sFileName; ^"Nsb&  
} 1q[vNP=g&  
koizk&)  
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public void setSFileName(String value) P=jbr"5Q:  
{ U2(|/M+  
sFileName = value; ZdJer6:Z}  
} c*"TmDY  
s3LR6Z7;i  
J&IFn/JK$  
public int getNSplitter() G3G"SJ np
 
{ 2\,vq R  
return nSplitter; 5E#koy7 $s  
} fW
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u+RdC
;_  
# Y*cLN`Y7  
public void setNSplitter(int nCount) jSj (ZU6  
{ }Pj3O~z  
nSplitter = nCount; 1jhGshhp  
} R{"7q:-  
} |F'k5Lh  
1wqsGad+;  
|5}~n"R5  
/* r|WoM39bp  
**Utility.java bh8IF,@a  
*/ \q8D7/q  
package NetFox; Va1 eG]jQ  
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mmV
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public class Utility {  t: =  
h|!F'F{  
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public Utility() O_p:`h:;M  
{ oR=^NEJv  
Ass8c]H@  
<Dr*^GX>?  
} V+()`>44  
oj7X9~ nd  
//线程睡眠 _`JYA  
public static void sleep(int nSecond) <h/\)bPB  
{ oK GFDl]3  
try{ p,=:Ff}~  
Thread.sleep(nSecond); "}b
k *2  
} $rySz7NI  
catch(Exception e) ^;2dZgJ4^  
{ <N%8"o  
e.printStackTrace (); \Mv8pU  
} ;n*N9-|.  
} O/IW.t  
qO<'_7TN[  
//日志 {V!Jj6n  
public static void log(String sMsg) =#i#IF42?  
{ j${:Y$V
mE  
System.err.println(sMsg); UC^Bn1  
} W"rX$D[Le  
1GY[
1M1^  
{Y9m;b,X  
public static void log(int sMsg) c 25wm\\  
{ W?"Z>tgp  
System.err.println(sMsg); yD`{9'L -  
} >?,arER  
} ?wps_XU  
4[]R?lL  
U4_<  
/* *HmL8c  
**TestMethod.java C.{*|#&GAt  
*/ icF -
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package NetFox; _c|>m4+X  
7cn"@h rJ  
;<#fZ0(l;  
public class TestMethod { hGH{Xp[mW  
 ]D7z&h  
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public TestMethod() oOuhbFu  
{ ///xx/weblogic60b2_win.exe 1;ulqO  
try{ EjB<`yT  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); S\Qh#yFT  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); #](k,% 2  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 4];Qpln  
fileFetch.start(); x#e(&OjN7  
} Y9m'RFZr  
catch(Exception e){e.printStackTrace ();} {=7W;uL  
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}
joifIp_  
=MG  
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public static void main(String[] args) :H<u@%  
{ ?T5^hQT   
new TestMethod(); _f,q8ZkSr  
} >ofS'mp  
} :Qu!0tY  
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