http断点续传简单实现（java)

/* z2jS(N?J1  
**SiteFileFetch.java ex.^V sf_  
*/ BO+to.  
package NetFox; (/S6b  
import java.io.*; 9RC:-d;;_  
import java.net.*; FjW%M;H  
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7
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public class SiteFileFetch extends Thread { \0)2 u[7  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 1I%niQv5t  
long[] nStartPos; //开始位置 L+lX
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long[] nEndPos; //结束位置 %r@:7/  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 O4!!*0(+91  
long nFileLength; //文件长度 _y:aPn  
boolean bFirst = true; //是否第一次取文件 PB#EU9  
boolean bStop = false; //停止标志 H|3CZ=U?  
File tmpFile; //文件下载的临时信息 IH"_6s#$&  
DataOutputStream output; //输出到文件的输出流 uM[[skc  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） z3M6<.K  
public SiteFileFetch(SiteInfoBean bean) throws IOException ?[.g~DK,  
{ O`_]n  
siteInfoBean = bean; 16"L;r  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); !,~C  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Gw#z:gX2  
if(tmpFile.exists ()) XvZ5Q  
{ R8|FqBs  
bFirst = false; Yez  
read_nPos(); aW#^@||B  
} ]sqp^tQ`e  
else LAGg(:3f3  
{ b~?3HY:t~K  
nStartPos = new long[bean.getNSplitter()]; C9j5Pd5q1L  
nEndPos = new long[bean.getNSplitter()]; "uBr]N:  
} 6Z-[-0o+g  
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} w!RJ8  
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public void run() -];Hb'M.!e  
{ h: zi
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//获得文件长度 E6xWo)`%5s  
//分割文件 hOe$h,E']  
//实例FileSplitterFetch qX]ej2  
//启动FileSplitterFetch线程 CYNpbv  
//等待子线程返回 V_9>Z?  
try{ RohD.`D  
if(bFirst) wEEFpn_   
{ >+S* Wtm5  
nFileLength = getFileSize(); % %QAC4  
if(nFileLength == -1) u]<`y6=&C  
{ Jh%k:TrBm  
System.err.println("File Length is not known!"); 9QkIMJf0e  
} $]b&3_O$N8  
else if(nFileLength == -2) CM+wkU ?,  
{ BgwZZ<B  
System.err.println("File is not access!"); pXe]hnY  
} *4 Kc "M  
else Q
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{ !e0/1 j=  
for(int i=0;i<nStartPos.length;i++) w&}UgtEm  
{ =e]Wt
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); 5O"wPsl  
} `=#ry*E^:  
for(int i=0;i<nEndPos.length-1;i++) |9 4xRC  
{ nmrdqSV  
nEndPos = nStartPos[i+1]; @3>nVa  
} !7anJl
  
nEndPos[nEndPos.length-1] = nFileLength; MM Nz2DEy[  
} JmVha!<
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} ;%PdSG=U  
]I0(_e|z}  
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//启动子线程 4?e7
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; kN$L8U8f  
for(int i=0;i<nStartPos.length;i++) ,lw<dB@7"5  
{ XJf1LGT5  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }UHoa  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), A\<WnG>xjP  
nStartPos,nEndPos,i); *!+?%e{;b  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); .:jfNp~jt  
fileSplitterFetch.start(); [u`9R<>c"U  
} FZtILlw  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), w5}2$r  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); _:9-x;0H2  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", "zN]gz=OV>  
nEndPos = " + nFileLength); )IZ~!N|-w  
// fileSplitterFetch[nPos.length-1].start(); vM2\tL@"  
JY@x.?N5$  
\JEI+A PY*  
//等待子线程结束 Gex%~';+q  
//int count = 0; {~:F1J~=  
//是否结束while循环 VUGVIy.  
boolean breakWhile = false; 5>[j^g+@  
>a1ovKF  
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while(!bStop) c9
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{ |CjE}5Op>  
write_nPos(); |/AY!Y3
 
Utility.sleep(500); }[I|oV5*+&  
breakWhile = true; ^<O:`c6_  
cc$+"7/J^c  
{!vz 6QDS  
for(int i=0;i<nStartPos.length;i++) w`OHNwXh#I  
{ oGi{d5  
if(!fileSplitterFetch.bDownOver) 3:WXrOl  
{ qbe9 CF'@_  
breakWhile = false; c6)q(zz  
break; &\o!-EIK8  
} awa$o  
} >P\/\xL=  
if(breakWhile) ZN?UkFnE  
break; ;}gS8I|  
dq ~=P>  
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//count++; 6~v|pA jY  
//if(count>4) />9?/&N6"  
// siteStop(); (Dx]!FFz  
} y|@=j~}Zq  
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System.err.println("文件下载结束！"); I|?Z.!I|  
} 675x/0}GO  
catch(Exception e){e.printStackTrace ();} FucLcq2Z  
} Ju7nvxC  
?#917M  
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//获得文件长度 y(RK|r  
public long getFileSize() 0Ie9T1D
=  
{ SggS8$
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int nFileLength = -1; fX2PteA0qX  
try{ S?_ ;$Cn  
URL url = new URL(siteInfoBean.getSSiteURL()); 3QrYH @7zx  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Xpd^^  
httpConnection.setRequestProperty("User-Agent","NetFox"); Ng3MfbFG  
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int responseCode=httpConnection.getResponseCode(); ]OOL4=b  
if(responseCode>=400) 0oi =}lV  
{ G&Sp }  
processErrorCode(responseCode); RT)*H>|  
return -2; //-2 represent access is error ' cl&S
:  
} 5? s$(Lt~  
V/G'{ q  
nEM>*;iE   
String sHeader; vWwnC)5  
fH7o,U|  
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for(int i=1;;i++) AhA
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{ $h-5PwHp  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); bG0t7~!{E  
//Utility.log(in.readLine()); #`mo5  
sHeader=httpConnection.getHeaderFieldKey(i); pcw^W  
if(sHeader!=null) |mfQmFF  
{ ArUGa(;f  
if(sHeader.equals("Content-Length")) 98os4}r  
{ y3K9rf  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); MD,}-m  
break; )[>b7K$f  
} 8]N+V:  
}
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else 5"5D(  
break; ?*z#G'3z1  
} :sBg+MS  
} g(Jzu'  
catch(IOException e){e.printStackTrace ();} v 6?{g  
catch(Exception e){e.printStackTrace ();} !z;a>[T'  
sgo({zA`i  
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Utility.log(nFileLength); z2&SZ.mk  
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return nFileLength; |wZ8O}O{E  
} F}A@H<?  
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M ,8r{[2  
//保存下载信息（文件指针位置） D!~-53f@  
private void write_nPos() ;jTP|q?|{  
{ hp}J_/+4n  
try{ @U%I 6 t  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ~n84x  
output.writeInt(nStartPos.length); 0EYK3<k9!  
for(int i=0;i<nStartPos.length;i++) S ;x;FU  
{ dm&F1NkT  
// output.writeLong(nPos); 9LGJ-gL  
output.writeLong(fileSplitterFetch.nStartPos); 0!rU,74I=  
output.writeLong(fileSplitterFetch.nEndPos); a'ViyTBo  
} F t%f"Z  
output.close(); K^k1]!W=  
} h@T}WZv  
catch(IOException e){e.printStackTrace ();} 7{:| )  
catch(Exception e){e.printStackTrace ();} RR><so%  
} {b>tX)Tep  
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//读取保存的下载信息（文件指针位置） d(w $! $"h  
private void read_nPos() u7&r'rZ1_!  
{ 5DfAL;o!  
try{ <$n%h/2%  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); WJZW5 Xt  
int nCount = input.readInt(); mk1;22o{TX  
nStartPos = new long[nCount]; H>e?FDs0*R  
nEndPos = new long[nCount]; F9ry?g=h  
for(int i=0;i<nStartPos.length;i++) [K[tL|EK  
{ _`L,}=um'  
nStartPos = input.readLong(); ?^us(o7-  
nEndPos = input.readLong(); bv>;%TF  
} Ix%h/=I  
input.close(); LKG],1n-  
} LQ?J r>4  
catch(IOException e){e.printStackTrace ();} 3KfZI&g  
catch(Exception e){e.printStackTrace ();} -,et. *  
} (j+C&*u
 
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private void processErrorCode(int nErrorCode) I~MBR2$9  
{ yE-&TW_q:>  
System.err.println("Error Code : " + nErrorCode); @dcT8 YC  
} _Q/D%7[pa  
(^Xp\dyZL  
pK4I?=A'  
//停止文件下载 m~#S76!w  
public void siteStop() '!Vn  
{ *~M=2Fj;i  
bStop = true; `|i #)  
for(int i=0;i<nStartPos.length;i++) ` &|
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fileSplitterFetch.splitterStop(); e%j+,)Ry  
:KZI+  
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} ^v3ytS  
} )ye[R^!}  
//负责部分文件的抓取 ^DVr>u  
**FileSplitterFetch.java bc5+}&W  
*/ ";9cYoKRY  
package NetFox; {J%hTjCw  
/Yc!m$uCW  
'@wYr|s4  
import java.io.*; R,/?p  
import java.net.*; TvAA  
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public class FileSplitterFetch extends Thread { ,Vt7Kiu  
' G-]>  
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String sURL; //File URL UMo=bs  
long nStartPos; //File Snippet Start Position &6PZX0M  
long nEndPos; //File Snippet End Position N6$pOQ  
int nThreadID; //Thread's ID oGly|L>  
boolean bDownOver = false; //Downing is over |h*H;@$  
boolean bStop = false; //Stop identical 57)S"  
FileAccessI fileAccessI = null; //File Access interface s7S
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4kNf4l9Y  
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+  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException w]UYD;f  
{ 3ZU`}  
this.sURL = sURL; \S}&QV  
this.nStartPos = nStart; &m`1lxT  
this.nEndPos = nEnd; vML01SAi  
nThreadID = id; ,2[laJ  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 u1ggLH!U  
} sZPPS&KoP3  
/lm;.7_J+  
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public void run() q>%KIBh(  
{ wtetB')yD  
while(nStartPos < nEndPos && !bStop) n%3rv?m7  
{ 2JYyvJ>  
/Bid:@R  
. 3=WE@M  
try{ OTL=(k  
URL url = new URL(sURL); {~k/xM.-  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); bec n$R  
httpConnection.setRequestProperty("User-Agent","NetFox"); $
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String sProperty = "bytes="+nStartPos+"-"; ln'7kg
 
httpConnection.setRequestProperty("RANGE",sProperty);  ]P(:z  
Utility.log(sProperty); d%81}4f:  
c7q1;X{:  
%(Nu"3|$K=  
InputStream input = httpConnection.getInputStream(); ._~_OVU  
//logResponseHead(httpConnection); (X,Ua+{  
/0d_{Y+9  
vO%n~l=  
byte[] b = new byte[1024]; p8oOm>B96n  
int nRead; x$J1%K*  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 2+TCFpv  
{ *.ri8  
nStartPos += fileAccessI.write(b,0,nRead); X7?p$!M6;B  
//if(nThreadID == 1) :qc@S&v@]  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); U GQ{QH  
} {%9)l,  
\ZigG{  
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Utility.log("Thread " + nThreadID + " is over!"); 7qA0bUee5  
bDownOver = true; cTHSPr?<  
//nPos = fileAccessI.write (b,0,nRead); xpx=t71Hq  
} Tw)nFr8oF]  
catch(Exception e){e.printStackTrace ();} `Ff3H$_*  
} KIC5U50J  
} d `>M-:dF  
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36*"oD=@  
//打印回应的头信息 8t!(!<iF0  
public void logResponseHead(HttpURLConnection con) #gMMhB=  
{ '~VKH}b  
for(int i=1;;i++) %UI.E=`n  
{ Lz2wOB1Zc+  
String header=con.getHeaderFieldKey(i); *j?tcxq
 
if(header!=null) ;RflzY|D  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); xM8}Xo  
Utility.log(header+" : "+con.getHeaderField(header)); fB:9:NX  
else hq6fDR
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break; 1Zx|
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} HlqCL1\<  
} Yewn  
cNtGjLpx;  
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public void splitterStop() 9 #TzW9  
{ sNc(aGvy  
bStop = true; 9AD`,]b  
} C~ t?<  
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} =SB#rCH  
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/* J_C<Erx[O  
**FileAccess.java .mn`/4  
*//文件访问(定位，写) >N@tInE  
package NetFox; Yc3\NqQM  
import java.io.*; ah1d0eP  
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rIH/<@+  
public class FileAccessI implements Serializable{ T1m"1Q  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ;n%SjQ'%  
RandomAccessFile oSavedFile; 8>x!n/z)
 
long nPos; ((Ak/qz  
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public FileAccessI() throws IOException j2c -01}  
{ 6v(}<2~  
this("",0); 
9 
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} X^ckTIdR  
8W#/=X
h?  
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public FileAccessI(String sName,long nPos) throws IOException MP(R2y  
{ btHN  
oSavedFile = new RandomAccessFile(sName,"rw"); seC]=UJh#>  
this.nPos = nPos; eqU2>bIf  
oSavedFile.seek(nPos); VR ^qwS/  
} k{;"Aj:iL  
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7yD=~l\Bbs  
public synchronized int write(byte[] b,int nStart,int nLen) M$~3`n*^  
{ $m,gQV~4  
int n = -1; cjAKc|NJ  
try{ <`k\kZM  
oSavedFile.write(b,nStart,nLen); Ni#!C:q  
n = nLen; {e\Pd!D?|  
} SNV~;@(h  
catch(IOException e) )Fx
"S.Ok  
{ 9]fhH  
e.printStackTrace (); M(|Qvh{Q6  
} v".q578 0B  
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JQ=i{
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return n; 0]4kR8R3[  
} %tul(Z~<1  
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} 8@]*X,umc  
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/* Z>gxECi  
**SiteInfoBean.java `b
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*/ Wt4ROj  
package NetFox; mbB,j~;^6H  
g\S@@0T{0  
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public class SiteInfoBean { :Rv?>I j  
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private String sSiteURL; //Site's URL %a=K:" oU[  
private String sFilePath; //Saved File's Path >}Qj|05G  
private String sFileName; //Saved File's Name Ec IgX_\  
private int nSplitter; //Count of Splited Downloading File 9pUvw_9MY  
fZ1v|  
:f%FM&b  
public SiteInfoBean() DX GClH  
{//nSplitter的缺省值为5 VN[C%C  
//default value of nSplitter is 5 59mNb:<  
this("","","",5); <6QG7i  
} uMVM-(g%  
%|E'cdvkX  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) @)PA9P |  
{ 6(awO2{BP  
sSiteURL= sURL; N`XJA-
DE  
sFilePath = sPath; 56gpAc  
sFileName = sName; U"$Q$ OFs  
this.nSplitter = nSpiltter; Ck;O59A"&-  
7?Q@Hj(:NT  
o#3?")>|  
} y_EkW f  
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public String getSSiteURL() u$ [R>l9  
{ +13h*  
return sSiteURL; wI.i\S  
} Vcn04j#Q  
Vij P;  
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public void setSSiteURL(String value) = ms(dr^n  
{ Rs_0xh  
sSiteURL = value; f?8cO#GU  
}  }/~%Ysl  
[ []'U'  
0^
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public String getSFilePath() MV +R$  
{ Dy6uWv,P  
return sFilePath; U |I>CDp  
} SY\ UuZ  
Y<|!)JLB2  
S\fEV"  
public void setSFilePath(String value) 3sG7G:4  
{ vSty.:bY\p  
sFilePath = value; X"WKgC g$  
} T=r-6eN  
r=GF*i[3  
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public String getSFileName() MuNM)pyxp  
{ 5`qt82Qm  
return sFileName; ,XT#V\qne  
} nk.Y#
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[Du@go1C  

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public void setSFileName(String value) n\d`Fk  
{ i`[5%6\"&  
sFileName = value; [MSLVTR  
} 9$,x^Qx  
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v*Tliw`-U  
public int getNSplitter() hsV+?#I  
{ )aoB-Lu  
return nSplitter; \zj _6Os  
} s_]p6M  
$=dp)  
V]b1cDx{  
public void setNSplitter(int nCount) &<I*;z6%t  
{ *r!f! eA:  
nSplitter = nCount; { 3``To$  
} m87,N~DP  
} k=w;jX&;`  

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-H1mKZDPP  
/* 2p\CCzw  
**Utility.java O%)@> 5#S  
*/ RjS;Ck@;  
package NetFox; )"?6EsSF  
qz7:jq3N-{  
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public class Utility { [NcS[*qp  
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public Utility() d,=Kv  
{ >Gbj1>C}  
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} eUQ.,mP  
!:e|M|T'I*  
//线程睡眠 Hw"ik6  
public static void sleep(int nSecond) "|W .o=R  
{ 4R!A.N
9  
try{ WelB+P2  
Thread.sleep(nSecond); hoxn!x$?  
} {zoUU  
catch(Exception e) &tY3nr  
{ ;/i"W  
e.printStackTrace (); vQrce&  
} Ta#vD_QP  
} N;,?k.vU  
97:1L4w.(  
//日志 * d6[kY  
public static void log(String sMsg) xGbr>OqkTX  
{ h&4ufx6  
System.err.println(sMsg); a]:tn:q  
} kN uDoo]z  
z9:@~3k.  
$iQ>c6  
public static void log(int sMsg) \~xI#S@  
{ kg[u@LgvoN  
System.err.println(sMsg); Ke[doQ#c  
} .(o]d{ '-}  
} Li ,B,  
E_&Hje|J_[  
".L+gn}u-  
/* 9fD4xkRS  
**TestMethod.java )/k0*:OMyO  
*/ 0z?b5D;  
package NetFox; ^}; 4r  
0?uX}8w  
k5G(7Ug=g~  
public class TestMethod { .d`+#1Ot(  
T=cSTS!P;q  
Rf@D]+v  
public TestMethod() U -~%-gFC  
{ ///xx/weblogic60b2_win.exe xO'I*)  
try{ sh.xp8^)^>  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 3WyK!@{  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); !f_GR Pj'  
SiteFileFetch fileFetch = new SiteFileFetch(bean); P# 2&?.d\  
fileFetch.start(); M<JJQh5  
}  p>v,b&06  
catch(Exception e){e.printStackTrace ();} -Hzn7L  
^|}C!t+  
2{s ND  
} J<DV7zV  
b~06-dk1  
ulFU(%&  
public static void main(String[] args) o;Ijv\Em  
{ |)6(_7e9  
new TestMethod(); |Hn[XRsf  
} QiWv  
} ':#?YQ}2  
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