http断点续传简单实现（java)

/* vciO={M  
**SiteFileFetch.java ,:[\h\5m  
*/ .)(5F45Wg  
package NetFox; B1^9mV'O  
import java.io.*; ,zF^^,lO7  
import java.net.*; B`<a~V  
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public class SiteFileFetch extends Thread { k2-+3zx  
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SiteInfoBean siteInfoBean = null; //文件信息Bean {!0f.nv  
long[] nStartPos; //开始位置 pNFVa<D  
long[] nEndPos; //结束位置 \wR;N/tg  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 _a]0<Vm C0  
long nFileLength; //文件长度 "!S7D>2y#  
boolean bFirst = true; //是否第一次取文件 Wf!u?nH.5  
boolean bStop = false; //停止标志 J;DTh ]z?:  
File tmpFile; //文件下载的临时信息 ,gO(zI-1  
DataOutputStream output; //输出到文件的输出流 ;$.^  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） BbIg]E/G  
public SiteFileFetch(SiteInfoBean bean) throws IOException 6N\f>c  
{ R4_B
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siteInfoBean = bean; S^Mx=KJ
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); >,6%Y
3  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ~'#yH#o  
if(tmpFile.exists ()) a&z$4!wQB  
{ rtxG-a56Q  
bFirst = false; oUd R,;h9  
read_nPos(); 2rGg  
} Ir6(EIwx0  
else j&-<e7O=  
{
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nStartPos = new long[bean.getNSplitter()]; *";O_
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nEndPos = new long[bean.getNSplitter()]; =G\N1E  
} ThiM6Hb  
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} \o}=ob  
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public void run() +.J/7gD  
{ q[TGEgG  
//获得文件长度 U|~I
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//分割文件 AA XQ+!  
//实例FileSplitterFetch kInU,/R*  
//启动FileSplitterFetch线程 m)ENj6A>yP  
//等待子线程返回 bH}?DMq]O  
try{ Yln[ZmK9g  
if(bFirst) P`L, eYc  
{ |hD)=sCj  
nFileLength = getFileSize(); _ SJFuv/  
if(nFileLength == -1) }X9G(`N(}  
{ EkpM'j
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System.err.println("File Length is not known!"); 8 3Tv-X  
} YBupC!R  
else if(nFileLength == -2) MlV3qM@  
{ `^df la  
System.err.println("File is not access!"); )mu[ye"p
 
} !
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else Ksff]##H  
{ 4Z0Y8y8)  
for(int i=0;i<nStartPos.length;i++) xM:9XhH1  
{ 06NW2A%wv  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); wBz5_ OFVw  
} }k0B   
for(int i=0;i<nEndPos.length-1;i++) s x2\  
{ b[^|.>b  
nEndPos = nStartPos[i+1]; v[]&yD  
} JIXZI\Fk  
nEndPos[nEndPos.length-1] = nFileLength; Ey&gZ$|&  
} ldWrv7.P  
} _F`RwBOjs  
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c,Yd#nokC  
//启动子线程 /DX6Hkkj%  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 7g.3)1  
for(int i=0;i<nStartPos.length;i++) ]6].l$%z#  
{ !h70<Q^  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Ap!Y 3C  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ZjveXrx  
nStartPos,nEndPos,i); r2=4Wx4(  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); {YIf rM  
fileSplitterFetch.start(); lbm ,#  
} &+")~2 +  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), evlz R/  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ^oDSU7j5,  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", m^KK #Hw/`  
nEndPos = " + nFileLength); \@$V^;OP/  
// fileSplitterFetch[nPos.length-1].start(); 4||dc}I"E  
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$  
)|B3TjHC  
//等待子线程结束 cIg+^Tl  
//int count = 0; \*\)zj*r  
//是否结束while循环 0[R7HX-@  
boolean breakWhile = false; Y(R .e7]  
7;SI=  
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while(!bStop) aK]H(F2#  
{ +&.wc;mi  
write_nPos(); c4iGtW  
Utility.sleep(500); :tT6V(-W  
breakWhile = true; a[7Lqu  
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for(int i=0;i<nStartPos.length;i++) a1gaB:w5n  
{ Yl"l|2 :  
if(!fileSplitterFetch.bDownOver) M"E7=J  
{ +t*Ks_V,*  
breakWhile = false; aUbmEHFTV  
break; i7foZ\btFc  
} Ax'o|RE)x  
} -P-&]F5  
if(breakWhile) ,Kwtp)EX  
break; yc.9CT
xx  
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':DLv
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//count++; 4{rj 4P?  
//if(count>4) zA*I=3E(  
// siteStop(); 8Lr&-w8J  
} @Q%<~b[y  
3pjK`"Nmz\  
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System.err.println("文件下载结束！"); Q$8K-5U%  
} Hg2Rcl  
catch(Exception e){e.printStackTrace ();} aW(Hn[}^  
} 'ARbJ1a  
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//获得文件长度 % jSB9  
public long getFileSize() pvYBhTz0  
{ "RLv{D<)J,  
int nFileLength = -1; WFG`-8_e[I  
try{ ;Miag'7  
URL url = new URL(siteInfoBean.getSSiteURL()); vY2^*3\<D  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); @w73U;9\  
httpConnection.setRequestProperty("User-Agent","NetFox"); 9_xJT^10  
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int responseCode=httpConnection.getResponseCode(); Zk>#T:{h  
if(responseCode>=400)
.A apO}{  
{ k%%0"+y#a  
processErrorCode(responseCode); #b94S?dq  
return -2; //-2 represent access is error @ ('/NjTZ  
} >$G'=N:=X&  
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String sHeader; v`Yj)  
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for(int i=1;;i++) XU|>SOR@z  
{ Y>Fh<"A|$  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); A8T8+M:  
//Utility.log(in.readLine()); &*#Obv  
sHeader=httpConnection.getHeaderFieldKey(i); =:_DXGW2H  
if(sHeader!=null) L)X[$:  
{ lw=
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if(sHeader.equals("Content-Length")) R3hyz~\x&  
{ v4vIcHDs  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); /&+*X)#v  
break; x
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} 85qD~o?O  
} Y+!z]S/x  
else 1"f)\FPGe  
break; @G^m+-  
} qh#?a'  
} OE=.@Ry"  
catch(IOException e){e.printStackTrace ();} OBL2W\{  
catch(Exception e){e.printStackTrace ();} jJyS^*.X  
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Utility.log(nFileLength); +;bP.[Z  
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return nFileLength; `y$@zT?j  
} 47!k!cHa  
L\xR<m<,  
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//保存下载信息（文件指针位置） ;k (M4?  
private void write_nPos() Igh=Z %  
{ @t2S"s$m  
try{ n;e.N:p  
output = new DataOutputStream(new FileOutputStream(tmpFile)); th%T(D5
n  
output.writeInt(nStartPos.length); 5Kl;(0B9  
for(int i=0;i<nStartPos.length;i++) "f:_(np,  
{ 6e%ZNw{#=  
// output.writeLong(nPos); B7(bNr  
output.writeLong(fileSplitterFetch.nStartPos); =F09@C,  
output.writeLong(fileSplitterFetch.nEndPos); _b9>ZF~  
} b<j*;n.  
output.close(); v(
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} ,c|Ai(U  
catch(IOException e){e.printStackTrace ();} 5DL(#9F8b9  
catch(Exception e){e.printStackTrace ();} z@[-+Q:  
} ht2J, 1t  
8*^*iEsR  
M8${&&[;  
//读取保存的下载信息（文件指针位置） Bdm05}c@u  
private void read_nPos() (} wMU]!_  
{ b\p2yJ\  
try{ WHcw5_3#  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); K"8!  
int nCount = input.readInt(); 10CRgrZ  
nStartPos = new long[nCount]; 2}rYH;Mx  
nEndPos = new long[nCount]; \m#{{SGm  
for(int i=0;i<nStartPos.length;i++) jD?*sd  
{ R%"'k<`#  
nStartPos = input.readLong(); AbIYdFXB  
nEndPos = input.readLong(); 465?,EpS  
} X'p%K/-m  
input.close(); 814cCrr,o  
} 0~BZh%s< (  
catch(IOException e){e.printStackTrace ();} |eK^Yhy
m  
catch(Exception e){e.printStackTrace ();} O+t'E9Fa  
} Iz8gZ:rd0  
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private void processErrorCode(int nErrorCode) L,
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{ ~0rvrDDg  
System.err.println("Error Code : " + nErrorCode); NXOcsdcZu  
} MP~+@0cv  
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//停止文件下载 L=&}s[5  
public void siteStop() bycnh  
{ P>'29$1'  
bStop = true; D&1(qi=x&  
for(int i=0;i<nStartPos.length;i++) =l>=]O~h  
fileSplitterFetch.splitterStop(); d?aZk-|c  
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} *mn"GK6  
} P?K
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//负责部分文件的抓取 :(;ho.zz  
**FileSplitterFetch.java j+Q+.39s-~  
*/ mp8Zb&Ggb  
package NetFox; <(l`zLf4p  
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import java.io.*; e8{!Kjiz  
import java.net.*; &t}6sD9o  
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public class FileSplitterFetch extends Thread { 1i;Cw/mr  
fYlqaO4[  
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String sURL; //File URL u24XuSe$  
long nStartPos; //File Snippet Start Position 3e1%G#fu  
long nEndPos; //File Snippet End Position `:Zgq+j&  
int nThreadID; //Thread's ID s1p<F,  
boolean bDownOver = false; //Downing is over XI"IEwB  
boolean bStop = false; //Stop identical "8E=*2fcw  
FileAccessI fileAccessI = null; //File Access interface =.qPjp_Qd  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Tn?D~?a
*O  
{ Z9i~>k  
this.sURL = sURL; e^v\K[  
this.nStartPos = nStart; #JR$RH  
this.nEndPos = nEnd; `bWc<
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nThreadID = id; @{ L|&Mk!  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 bjq.nn<=  
} o)8VJ\ &  
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public void run() " "S&zN  
{ B5[As8
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while(nStartPos < nEndPos && !bStop) M-(,*6Q  
{ 1jd.tup  
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try{ \/9O5`u*V  
URL url = new URL(sURL); .Dy2O*`  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); o1H6E1$=  
httpConnection.setRequestProperty("User-Agent","NetFox"); B/B`=%~5_^  
String sProperty = "bytes="+nStartPos+"-"; H%ScrJ#V  
httpConnection.setRequestProperty("RANGE",sProperty); Nx!7sE*b$1  
Utility.log(sProperty); ,My'_"S?  
 p4P"U  
MRzY<MD  
InputStream input = httpConnection.getInputStream(); yO@@-)$[y  
//logResponseHead(httpConnection); &D&U!3~(  
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j{@li1W@  
byte[] b = new byte[1024]; ~xcU6@/  
int nRead; h<7@3Ur  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) zrwzI+4  
{ zuF]E+  
nStartPos += fileAccessI.write(b,0,nRead); lU`t~|>r+  
//if(nThreadID == 1) ,M :j5  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); I p|[  
} W+Ou%uv}S  
?y,KN}s_  
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Utility.log("Thread " + nThreadID + " is over!"); tO3#kV\,  
bDownOver = true; TXqtE("BDl  
//nPos = fileAccessI.write (b,0,nRead); ^~s!*T)\  
} NleMZ  
catch(Exception e){e.printStackTrace ();} $&sV.fGu  
} w`atk=K  
} 28j/K=0(  
)ib$*dmUP  
VdGpreRPC  
//打印回应的头信息 !:v7SRUXb  
public void logResponseHead(HttpURLConnection con) l!:L<B  
{ biRkqc;  
for(int i=1;;i++) 9[[$5t`8  
{ h r6?9RJY  
String header=con.getHeaderFieldKey(i); "YVr/u  
if(header!=null) [J55%N;#1  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); >uFFTik  
Utility.log(header+" : "+con.getHeaderField(header)); K1p.{  
else |<%v`*  
break; T&j:gg  
} YR[I,j  
} (IIZvCek  
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public void splitterStop() Cv;#8Wj}  
{ tD,I7%|@  
bStop = true; Y/ %XkDC~  
} szD9z{9"y  
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} h+Y>\Cxg  
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/* V`G^Jyj  
**FileAccess.java k7]4TIUD*  
*//文件访问(定位，写) g!Ui|]BI9  
package NetFox; |W}D_2  
import java.io.*; :k2J &@8  
;WgzR_'!'  
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public class FileAccessI implements Serializable{ Y Azj>c&  
'Z)#SzY
 
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 AYDAt5K_  
RandomAccessFile oSavedFile; }|)T<|Y;  
long nPos; ;D@F  
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n*caP9B  
public FileAccessI() throws IOException V(Cxd.u  
{ |hX\ep  
this("",0); R_"6E8N  
} #}Bv/`t  
;@O8y\@  
)k]{FM  
public FileAccessI(String sName,long nPos) throws IOException
! 6R|  
{ k#Qjm9V  
oSavedFile = new RandomAccessFile(sName,"rw"); h?vny->uJ  
this.nPos = nPos; <- R%  
oSavedFile.seek(nPos); \\{78WDA  
} w}8=sw  
l9n$cv^  
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public synchronized int write(byte[] b,int nStart,int nLen) yZb})4.  
{ n^nQrRIp  
int n = -1; (%G>TV  
try{ _qH]OSo  
oSavedFile.write(b,nStart,nLen); JURg=r]LI  
n = nLen; iF_u/#  
} YoZd,} i  
catch(IOException e) M0hR]4T  
{ g!i45]6[Nw  
e.printStackTrace (); Nh !U  
} %VE FruM  
=FMrVE  
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return n; =@nW;PUZ  
} X5= Ki $+  
e~
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<~e*YrJ?-  
} 2o7o~r  
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/* YB4|J44Y  
**SiteInfoBean.java zLPCWP.u  
*/ @f-rS{  
package NetFox; aw7pr464  
TC ;Aj|)N  
CljEC1S#  
public class SiteInfoBean { R5 EC/@  
X*e:MRw[  
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private String sSiteURL; //Site's URL u%Z4 8wr  
private String sFilePath; //Saved File's Path FH;)5GGnv  
private String sFileName; //Saved File's Name Eb8z`@p  
private int nSplitter; //Count of Splited Downloading File y;hco  
wD@ wOC  
}~#qD
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public SiteInfoBean() 2XeNE[  
{//nSplitter的缺省值为5 0IsnG?"  
//default value of nSplitter is 5 /|<0,ozoJ  
this("","","",5); {Hw$`wL  
} d"+ _`d=`  
WhV>]B2+"  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) "azrcC  
{ =I+5sCF{g  
sSiteURL= sURL; > !HC ?  
sFilePath = sPath; <"S/M]9  
sFileName = sName; +jp^  
this.nSplitter = nSpiltter; o7g6*hJz  
?\a';@h  
,Nev7X[0  
} >JN[5aus  
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?QzN\fY;  
public String getSSiteURL() ~ o5h}OU"  
{ `]<~lf  
return sSiteURL; E8We2T[^M  
} |U="B4  
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q -^Z=,<  
public void setSSiteURL(String value) uL@'Hv A  
{ $7\hszjZ  
sSiteURL = value; zx5t gZd,N  
}
m RtE~~p  
8SMa5a{  
oc&yz>%q  
public String getSFilePath() @wXo{p@W  
{ ?^: xNRE$j  
return sFilePath; `ln=D$  
} pB,@<\l %  

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}5ONDg(I~  
public void setSFilePath(String value) \Eyy^pb  
{ !q*]_1  
sFilePath = value; =/HTe&  
} 8f#&CC!L  
4buzx&  
T<ekDhlr  
public String getSFileName() 5LxzET"P  
{ cUr'mb  
return sFileName; ]F,v#6qi  
} a7l-kG=R;  
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public void setSFileName(String value) iI%"]- 0@1  
{ ,vUMy&AV  
sFileName = value; n!\&X9%[8  
} i52:<< 8a  
jhSc9  
zDofe*  
public int getNSplitter() JxLD}$I  
{ 9Z_98Rh  
return nSplitter; (g]J hG  
} 2qUC@d<K  
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p[-buB]  
public void setNSplitter(int nCount) K3^N_^H  
{ d/:zO4v3  
nSplitter = nCount; ws$!-t4<(  
} bi[gyl#  
} ~*h` ?A0  
``mW\=fe  
NEh5   
/* Y r^C+Oyg  
**Utility.java t^qPQ;"=,  
*/ 3pKr {U92  
package NetFox; u9"1%  
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public class Utility { G#;$;  
u;*Wc9>sU  
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public Utility() bqAv)2  
{ "!6 Ax-'  
vxzOG?Xc:  
')/yBH9mR  
} g2WDa'{L  
I)Dd"I  
//线程睡眠 ,#42ebGHR  
public static void sleep(int nSecond) $z~sN  
{ Q
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try{ tc@([XqH  
Thread.sleep(nSecond); ^\uj&K6l  
} i
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catch(Exception e) .)>DFGb>H  
{ `UpZk?k  
e.printStackTrace (); Yl+r>+^  
} Z`5v6"Na  
} 1wl8  
daIt `}s  
//日志 .4
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public static void log(String sMsg) KF|<A@V  
{ AopCxaJ`  
System.err.println(sMsg); ui,#AZQ#{4  
} [*O#6Xu  
K
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)} y1  
public static void log(int sMsg) eXI^9u
H  
{ 2c.~cNx`q[  
System.err.println(sMsg); HPGi5rU  
} X
TD_q  
} N6Fj}m&E  
z&o"K\y\  
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/* I%43rdoPe  
**TestMethod.java tdn[]|=  
*/ *ws!8-)fH  
package NetFox; xoD5z<<  
e}?#vTRI}  
8]Xwj].^C  
public class TestMethod { n)w@\Uyc  
3 [lF  
y_$=Pu6H  
public TestMethod() 9qe6hF/29  
{ ///xx/weblogic60b2_win.exe x
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try{ XX5 ):1  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); sH(AsKiNKe  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); [EDw0e  
SiteFileFetch fileFetch = new SiteFileFetch(bean); >8~+[e  
fileFetch.start(); ;SF0}51  
} iq '3.-xYr  
catch(Exception e){e.printStackTrace ();} !Jw   
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y(B~)T~e@  
} W;coi4   
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public static void main(String[] args) 9~DoF]TM  
{ _gK@),de  
new TestMethod(); )p>BN|L  
} 7'_zJI^  
} &3mseU  
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