http断点续传简单实现（java)

/* jQ_|z@OV  
**SiteFileFetch.java ;/)Mcx]n  
*/ ahi57r[  
package NetFox; C@UJOB  
import java.io.*; !8"$d_=h  
import java.net.*; T?]kF-   
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public class SiteFileFetch extends Thread { n2y/zP>TC  
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SiteInfoBean siteInfoBean = null; //文件信息Bean /,uSCITD  
long[] nStartPos; //开始位置 Gkodk[VuLs  
long[] nEndPos; //结束位置 pT ocqJ22  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ;(Ajf.i  
long nFileLength; //文件长度 iQm.]A  
boolean bFirst = true; //是否第一次取文件
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boolean bStop = false; //停止标志 j_6`s!Yw  
File tmpFile; //文件下载的临时信息 LE0J
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DataOutputStream output; //输出到文件的输出流 k qY3r &  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） z"s%#/#  
public SiteFileFetch(SiteInfoBean bean) throws IOException mS)|6=Y  
{ J^g,jBk  
siteInfoBean = bean; 0,~6TV<K  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); GOZQ5m -  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); q(jkit~`A  
if(tmpFile.exists ()) vU8FHVytV  
{ 7i+!^Qj?y  
bFirst = false; M]4=(Vv+5  
read_nPos(); h[-d1bKwS  
} !}L~@[v,uL  
else i>]<*w  
{ Av;q:x?  
nStartPos = new long[bean.getNSplitter()]; ,>QMyI hv  
nEndPos = new long[bean.getNSplitter()]; *b6I%MZn  
} dIk8TJ  
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} /+x#V!zM  
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public void run() t4jd KYA  
{ j5,^
9'  
//获得文件长度 (/"K+$8'  
//分割文件 nI`f_sp  
//实例FileSplitterFetch wZo.ynXT  
//启动FileSplitterFetch线程 ~<2 IIR$H  
//等待子线程返回 hr_9;,EPh  
try{ OD?
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if(bFirst) l}Q"Nb)  
{ O:5Rp_?^  
nFileLength = getFileSize(); uXG`6|
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if(nFileLength == -1) tL={y*  
{ '#,e @v  
System.err.println("File Length is not known!"); B0b[p*gIl  
} (<bm4MPf  
else if(nFileLength == -2) d%#!nq{vd  
{ m?D <{BQ;  
System.err.println("File is not access!"); bVa+kYE  
} *]}CSZ[>  
else {uaZ<4N.  
{ 4GU/V\e|  
for(int i=0;i<nStartPos.length;i++) eq@am(#&kY  
{ <THZ2`tTK3  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); d}{LM!s  
} 7xv4E<r2  
for(int i=0;i<nEndPos.length-1;i++) ,]PyDq6  
{ i}/e}s<-6  
nEndPos = nStartPos[i+1]; (|0.m8D~D  
} BR& Aq  
nEndPos[nEndPos.length-1] = nFileLength; hzT{3YtY2  
} nabBU4;h  
} 99l>CYXd  
/~3N@J  
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//启动子线程 KA5~">l  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; AW,v  
for(int i=0;i<nStartPos.length;i++) V;h=8C5J  
{ e/"yGQu  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), X q}Ucpj  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), HE#,(;1i  
nStartPos,nEndPos,i); (O)\#%,@R  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Q0zW ]a  
fileSplitterFetch.start(); {fGd:2dh  
} \H Wcd|  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), EJf#f
 
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); B :.@Qi^  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", GXDC@+$14  
nEndPos = " + nFileLength); hpbwZ  
// fileSplitterFetch[nPos.length-1].start(); G(U9rJ9  
lLb:f6N  
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//等待子线程结束 Ds%9cp*6  
//int count = 0; ~Cjz29|gp  
//是否结束while循环 "w}-?:# j  
boolean breakWhile = false; f4]N0  
"z rA``  
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while(!bStop) 0HGlf  
{ [8>z#*B  
write_nPos(); BdN8 ^W  
Utility.sleep(500); :83,[;GO2  
breakWhile = true; FJP< bREQ  
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for(int i=0;i<nStartPos.length;i++) BjJ,"sT  
{ K)\(wxv  
if(!fileSplitterFetch.bDownOver) 4p.^'2m  
{ PG{i,xq_B{  
breakWhile = false; ?b||Cr  
break; =43I1&_   
} 0cHfxy3  
} O^5UB~  
if(breakWhile) KAd_zkUA  
break; +7,8w  
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b2N6L2~V  
//count++; 6X/wdk  
//if(count>4) qE )Y}oN  
// siteStop(); taweGc%~  
} F\a]n^ Y  
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System.err.println("文件下载结束！"); g>so R&*  
} 9YB2e84j  
catch(Exception e){e.printStackTrace ();} (+* ][|T  
} i+g~ Uj}h  
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//获得文件长度 93j{.0]X  
public long getFileSize() M\Se_  
{ a6%@d_A  
int nFileLength = -1; bW53" `X  
try{ v
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URL url = new URL(siteInfoBean.getSSiteURL()); [ `7%sn]$  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 3UdU"d[75  
httpConnection.setRequestProperty("User-Agent","NetFox"); v:E;^$6Vn  
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int responseCode=httpConnection.getResponseCode(); 74+A+SK[  
if(responseCode>=400) (S`6Q  
{ zDD4m`2  
processErrorCode(responseCode); aX;A==>  
return -2; //-2 represent access is error hk%k(^ekU]  
} Hou*lCA
  
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String sHeader; |( G2K'Ab  
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w  
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for(int i=1;;i++) fAGctRGH  
{ `H\)e%]  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Y;Ap9i*  
//Utility.log(in.readLine()); 8nCp\0  
sHeader=httpConnection.getHeaderFieldKey(i); )
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if(sHeader!=null) i31<].|kA*  
{ `H>b5  
if(sHeader.equals("Content-Length")) t2- ^-g6  
{ FZF @  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); [#Y' dFQ  
break; ciudRK63M  
} uRE*%d>  
} )P?IqSEA%  
else re^Hc(8M  
break; >c4/?
YV  
} v?%LQKO  
} ]IZ>2!6r
  
catch(IOException e){e.printStackTrace ();} ?s?$d&h  
catch(Exception e){e.printStackTrace ();} =7%oE[  
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Utility.log(nFileLength); @Y}uZ'jt'  
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return nFileLength; WNs}sNSf  
} ZtK\HDdp  
Gh}yb-$N`&  
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//保存下载信息（文件指针位置） :]PM_V|  
private void write_nPos() Dw_D+7>(v  
{ Iy';x  
try{ <xo-Fv  
output = new DataOutputStream(new FileOutputStream(tmpFile)); */z??fI27  
output.writeInt(nStartPos.length); 06 i;T~Y  
for(int i=0;i<nStartPos.length;i++) N2ied^* 0  
{ MV0Lq:# N  
// output.writeLong(nPos); G,XPT,:%  
output.writeLong(fileSplitterFetch.nStartPos); d;7uFh|o  
output.writeLong(fileSplitterFetch.nEndPos); m}3gZu]  
} s =Umj'1k  
output.close(); ?<U
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} =Q<L eh=G  
catch(IOException e){e.printStackTrace ();} kkS~4?-*  
catch(Exception e){e.printStackTrace ();} @%hCAm  
} .&1C:>  
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//读取保存的下载信息（文件指针位置） AVl~{k|  
private void read_nPos() Wh( |+rJ?Z  
{ x[(?#  
try{ o31Nmy Ni  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); rY0u|8.5Q  
int nCount = input.readInt(); + H_WlYg-  
nStartPos = new long[nCount]; +*}{`L- :  
nEndPos = new long[nCount]; ; A,#;
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for(int i=0;i<nStartPos.length;i++) /KCPpERk{  
{ Nc)J18  
nStartPos = input.readLong();
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nEndPos = input.readLong(); p`F9Amb  
} *|% ^0#$c  
input.close(); B=Ym x2A9]  
} . ]@=es  
catch(IOException e){e.printStackTrace ();} 2HD]?:Fk7  
catch(Exception e){e.printStackTrace ();} WG7k(Sp]  
} nV*y`.+  
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private void processErrorCode(int nErrorCode)  k5`OH8G  
{ 
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System.err.println("Error Code : " + nErrorCode); '?QuJFki  
} @+LfQY  
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//停止文件下载 ,=QM#l]  
public void siteStop() b'YE9E  
{ b:J(b?  
bStop = true; MZ>6o5K|  
for(int i=0;i<nStartPos.length;i++) FLZWZ;  
fileSplitterFetch.splitterStop(); S4CbyXW  
ln!'_\{  
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} (u3s"I d  
} "2?l{4T\  
//负责部分文件的抓取 23!;}zHp  
**FileSplitterFetch.java o|BP$P8V  
*/ MJ`3ta  
package NetFox; kc `V4b%  
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import java.io.*; 9BEFr/.  
import java.net.*; '8Ztj  
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public class FileSplitterFetch extends Thread { FR[ B v  
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String sURL; //File URL v``-F(i$  
long nStartPos; //File Snippet Start Position )E#2J$TD  
long nEndPos; //File Snippet End Position =sJ _yq0#R  
int nThreadID; //Thread's ID [,RI-#n  
boolean bDownOver = false; //Downing is over 3REx45M2  
boolean bStop = false; //Stop identical DQ#H,\^<  
FileAccessI fileAccessI = null; //File Access interface I` K$E/ns  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException gi/@j  
{ $2^
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this.sURL = sURL; + @9.$6N  
this.nStartPos = nStart; &,\=3'  
this.nEndPos = nEnd; V r(J+1@  
nThreadID = id; ?~"bR%  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 GNf482  
} fWc|gq  
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public void run() 6lwta`2  
{ ]uj=:@  
while(nStartPos < nEndPos && !bStop) &3F}6W6A  
{ OO dSKf8  
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try{ T<3BT  
URL url = new URL(sURL); fKC3-z
m  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); =<r8fXWZ  
httpConnection.setRequestProperty("User-Agent","NetFox"); >(w2GD?  
String sProperty = "bytes="+nStartPos+"-"; `afIYXP  
httpConnection.setRequestProperty("RANGE",sProperty); U[L9*=P;  
Utility.log(sProperty); VGHWNMT  
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InputStream input = httpConnection.getInputStream(); I:bD~Fb3  
//logResponseHead(httpConnection); vu!d)Fy  
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byte[] b = new byte[1024]; T{qTj6I  
int nRead; H1GRMDNXOA  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Jj~EiA  
{ T9)nQ[  
nStartPos += fileAccessI.write(b,0,nRead); &cWjEx  
//if(nThreadID == 1) O%g$9-?F0  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); FGO[ |]7IN  
}
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Utility.log("Thread " + nThreadID + " is over!");
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bDownOver = true; WwH+E]^e+  
//nPos = fileAccessI.write (b,0,nRead); SG}V[Glk  
} Gb[`R}^dq  
catch(Exception e){e.printStackTrace ();} ;6@r-r  
} 2?m.45`  
} :j|IP)-f  
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//打印回应的头信息 nJ4@I7Sk;  
public void logResponseHead(HttpURLConnection con) gBT2)2]  
{ 7n]65].t  
for(int i=1;;i++) Uv YF[@  
{ 7Dnp'*H  
String header=con.getHeaderFieldKey(i); l`kWz5[~  
if(header!=null) 5aad$f  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); .=m,hu~  
Utility.log(header+" : "+con.getHeaderField(header)); x!\ONF5$  
else oH
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break; 43?^7_l-  
} _&K  
} |KB0P@
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public void splitterStop() !D!~^\  
{ hA\K</h.  
bStop = true; [."[pY  
} `V)Z)uN{0  
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} ?JL7=o X  
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 ^pn(=4  
/* tiN?/  
**FileAccess.java b:qY gg  
*//文件访问(定位，写) 2G$SpfeIu  
package NetFox; pg]BsJN  
import java.io.*; ,-x!$VqS  
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public class FileAccessI implements Serializable{ 1ygpp0IGJ  
1c JF/"v  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 iU6Gp-<M,  
RandomAccessFile oSavedFile; rkiT1YTY  
long nPos; )54%HM_$k  
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public FileAccessI() throws IOException ?"?6,;F(4  
{ Z3[S]jC  
this("",0); Y#!h9F  
} 4f(Kt,0  
6}FO[  
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public FileAccessI(String sName,long nPos) throws IOException Sq:0w  
{ $}")1|U,X  
oSavedFile = new RandomAccessFile(sName,"rw"); As+t#
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this.nPos = nPos; -v6M<  
oSavedFile.seek(nPos); x `V;Y]7'  
} p ?wI9GY  
'`1CBU$  
(98Nzgxgx}  
public synchronized int write(byte[] b,int nStart,int nLen) :e
o  
{ e#/E~r&  
int n = -1; 1-.~7yC  
try{ 9&RFO$WH  
oSavedFile.write(b,nStart,nLen); 29XL$v],  
n = nLen; ?FfC  
} Kscd}f)yx?  
catch(IOException e) EGl^!.'  
{ "UwH\T4I  
e.printStackTrace (); czlFr|O;  
} E^U0f/5 m  
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8w({\=
 
return n; iAa;6mH  
} "`6n6r42  
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} A.UUW  
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/* *,BzcZ  
**SiteInfoBean.java *%KKNT'*  
*/ 2w)-\/j}  
package NetFox; C"IK
t  
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public class SiteInfoBean { G%d (
 
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private String sSiteURL; //Site's URL &~CY]PN.  
private String sFilePath; //Saved File's Path B c2p(z4  
private String sFileName; //Saved File's Name Pz$R(TV  
private int nSplitter; //Count of Splited Downloading File q\\gpCgp  
v
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public SiteInfoBean() Ecs,$\  
{//nSplitter的缺省值为5 %v2R.?F8  
//default value of nSplitter is 5 H(Eh c  
this("","","",5); I@\OaUGr+  
} HYmn:?H  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) _#vrb;.+  
{ y!]CJigpZ  
sSiteURL= sURL; ExRe:^yU\  
sFilePath = sPath; ?k(\ApVHj  
sFileName = sName; vX]Gf4,  
this.nSplitter = nSpiltter; ytNO*XoR  
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} x`6<m!d`  
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public String getSSiteURL() s=42uKz  
{ [V:\\$  
return sSiteURL; 2k<;R':  
} fA89|NTSUh  
|r bWYl.b  
<oz!H[!  
public void setSSiteURL(String value) zRPeNdX  
{ vB+ '  
sSiteURL = value; }pJwj  
} P (S>=,Y&  
Y
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public String getSFilePath() ]5%/3P,/  
{ }- Wa`t7U  
return sFilePath; \rPbK+G.  
} O(_[ayE  
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public void setSFilePath(String value) Uk\Id~xLV  
{ H<1WbM:w  
sFilePath = value; 6S~sVUL9`  
} V%Sy"IG  
VU@9@%TN  
_SA5e3#   
public String getSFileName() cp o-.  
{ U)3DQ6T99  
return sFileName; MMj9{ou  
} ,*7d  
-ig6w.%lk  
 wd)jl%  
public void setSFileName(String value) /@|/^vld  
{ f^VP/rdg  
sFileName = value; c*@G_rb  
} QD%L0;j  
<^$<#Kd  
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public int getNSplitter() 2+X\}s1vN  
{ ?@V[#.  
return nSplitter; 5#K
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} %AQIGBcgL  
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k?'B*L_Mzv  
public void setNSplitter(int nCount) ?Ae ven  
{ 4rrSb*
  
nSplitter = nCount; ;amXY@RmH  
} w}=5ElB  
} &iV,W4  
o^ XtU5SVq  
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/* |DsnNk0c
 
**Utility.java
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*/ ~*wk6&|  
package NetFox; ^`G}gWBx}w  
l]5w$dded~  
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public class Utility { _8E/)M  
&%-73nYw  
N ,z6y5Lu  
public Utility() >vA2A1WhW  
{ r-<F5<H+K@  
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} ,{mCf^  
?Ec7" hK  
//线程睡眠 ow]053:i  
public static void sleep(int nSecond) MNV% =G  
{ Gh}*q|Lz  
try{ ukUGvK  
Thread.sleep(nSecond); ' MxrQ;|S  
} ,S!azN=  
catch(Exception e) }+sT4'Ah>  
{ Er{>p|n=  
e.printStackTrace (); yNTK
.  
} 8e(\%bX  
} L+q/){Dd(  
>qF CB\(  
//日志 ^- d%r  
public static void log(String sMsg) -(=eM3o-9m  
{ 3p'I5,}  
System.err.println(sMsg); Cid ;z  
} GmP@;[H"  
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1Yn +<I  
public static void log(int sMsg) S.f5v8  
{ Pjc Tx +  
System.err.println(sMsg); .qZI$ l.  
} f=9|b  
} qXwPDq/  
&mx)~J^m  
Dg?:/=,=9r  
/* v'3J.?N  
**TestMethod.java .yEBOMNZ  
*/ 7yh/BZ1  
package NetFox; aSnFKB  
eYvWZJa4  
55fC~J<  
public class TestMethod { ^=-y%kp"  
Sb82}$sO  
{.INnFGP@)  
public TestMethod() nX`u[ks  
{ ///xx/weblogic60b2_win.exe ]@u6HH~^  
try{ RtM8yar+sn  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); EU+S^SyZi  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); )z28=
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SiteFileFetch fileFetch = new SiteFileFetch(bean); Ptdpj)oi&Q  
fileFetch.start(); e(<str
>  
} [
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catch(Exception e){e.printStackTrace ();} s|y "WDyx5  
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} #iHs* /85  
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public static void main(String[] args) %Da1(bBh  
{ WL"^>[Vq  
new TestMethod(); TtTj28k7  
} j=r P:#  
} @pRlxkvV  
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