http断点续传简单实现（java)

/* 5tdFd"oo  
**SiteFileFetch.java rz+)z:u  
*/ {U?/u93~  
package NetFox; hm*1w6 =  
import java.io.*; )D\!
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import java.net.*; X31[  
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public class SiteFileFetch extends Thread { 15U]/?jv8  
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SiteInfoBean siteInfoBean = null; //文件信息Bean b-ZC~#?|b  
long[] nStartPos; //开始位置 ^&F8NEb=2>  
long[] nEndPos; //结束位置 h)fJ2]JW8W  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 0}}b\!]9  
long nFileLength; //文件长度 xTiC[<j  
boolean bFirst = true; //是否第一次取文件 f40xS7-Q0  
boolean bStop = false; //停止标志 R8O;8c?D  
File tmpFile; //文件下载的临时信息 1vk&;  
DataOutputStream output; //输出到文件的输出流 Opx"'HC@G  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） |(G^3+5Uwm  
public SiteFileFetch(SiteInfoBean bean) throws IOException HJWk%t<  
{ .Y|5i^i9{  
siteInfoBean = bean; aqJ>l}{  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); C ioM!D  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); o|u<tuUW  
if(tmpFile.exists ()) K,(37Id'  
{ Kq&b1x  
bFirst = false; W: R2e2  
read_nPos(); k|Mj|pqA  
} z/Z 0cM#  
else 3}*)EC  
{ 8 :B(}Y4K  
nStartPos = new long[bean.getNSplitter()]; *{[jO&
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nEndPos = new long[bean.getNSplitter()]; Hj\>&vMf  
} KnK8\p88\  
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} EAafi<n  
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public void run() ZyAm:yO  
{ jyB^a;-  
//获得文件长度 1 ? be  
//分割文件 f/+UD-@%m  
//实例FileSplitterFetch OwRH :l  
//启动FileSplitterFetch线程 7HfA{.|m  
//等待子线程返回 L *",4!  
try{ bit@Kv1<C  
if(bFirst) Tk1U  
{ 'PiQ|Nnb|  
nFileLength = getFileSize(); bDK%vx!_  
if(nFileLength == -1) 4'EC(NR7N  
{ fP 4  
System.err.println("File Length is not known!"); J;@g#h?  
} Y6<"_  
else if(nFileLength == -2) 93I.Wp_{  
{ >Z%qkU/  
System.err.println("File is not access!"); EhJpJb[Z  
} -aj)
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else ]1YyP  
{ fbv%&z  
for(int i=0;i<nStartPos.length;i++) \ k&(D*u  
{ o+-G@16  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Nr6[w|Tzd  
} ~t0\Q; @($  
for(int i=0;i<nEndPos.length-1;i++) *F[;D7sZ~  
{ 3pQ^vbQ"  
nEndPos = nStartPos[i+1]; y?Vsp<  
} 1=NP=ZB  
nEndPos[nEndPos.length-1] = nFileLength; ;(0<5LQ  
} FQ6jM~  
} XQW9/AzNf  
_}G1/`09#  
/D@(o`a  
//启动子线程 N5m+r.<;  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; lxSCN6  
for(int i=0;i<nStartPos.length;i++) 67,@*cK3?J  
{ `]*BDSvE  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), #ArMX3^+w7  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), d4(!9O.\  
nStartPos,nEndPos,i); w+MCOAB  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); w&U>w@H^  
fileSplitterFetch.start(); 4<c#3]  
} #@qd.,]2  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), qC|$0  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); q,ur[ &<  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", JIJ79HB  
nEndPos = " + nFileLength); P`ZYm  
// fileSplitterFetch[nPos.length-1].start(); 7R4xJ H  
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\~ACWF7l  
//等待子线程结束 uIeD.I'@{5  
//int count = 0; XH
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//是否结束while循环 y&F0IJ|`@M  
boolean breakWhile = false; (bT3 r_  
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~]Md*F[4*e  
while(!bStop) Aw~N"i  
{ A~Uqw8n$\  
write_nPos(); i7
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Utility.sleep(500); |~V`Es +j  
breakWhile = true; '5V#sq;Z  
estDW1i)  
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for(int i=0;i<nStartPos.length;i++) uW@o,S0:  
{ w26x)(7  
if(!fileSplitterFetch.bDownOver) W'0(0;+G/j  
{ 8r|5l~`8  
breakWhile = false; !}[cY76_  
break; ~sk{O%OI  
} O:^m#:[cE  
} YY? }/r  
if(breakWhile) (txr%Z0E  
break; 9gS.G2  
B^{87YR  
+0)zB;~7  
//count++; F~qiNV  
//if(count>4) R3`Rrj Z  
// siteStop(); `%a+LU2  
} utJz e  
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'J0Erk8(  
System.err.println("文件下载结束！"); ,:G3Y )  
} kJy bA  
catch(Exception e){e.printStackTrace ();} ab5uZ0@  
} _jhdqON6E  
Vv]81y15Q;  
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//获得文件长度 W;^bc*a_  
public long getFileSize() 74hQ?Atw:  
{ $AI0&#NM  
int nFileLength = -1; bM%c*_$F7  
try{ -4}I02  
URL url = new URL(siteInfoBean.getSSiteURL()); E#cW3\)  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); W@:a3RJ  
httpConnection.setRequestProperty("User-Agent","NetFox"); :zL.dJwa  
":o1g5?  
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int responseCode=httpConnection.getResponseCode(); pPezy:  
if(responseCode>=400) l}Fa-9_'  
{ ;4g_~fB  
processErrorCode(responseCode); #9F
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return -2; //-2 represent access is error OP-%t\sj>  
} +.p$Yi`
 
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String sHeader; guD?~-Q  
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for(int i=1;;i++) @3UVl^T  
{ Q I.
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ,;_D~7L  
//Utility.log(in.readLine()); N,><,7!q$,  
sHeader=httpConnection.getHeaderFieldKey(i); 0 CJ4]mYl  
if(sHeader!=null) ji &*0GJQ  
{ )kE(%q:*P$  
if(sHeader.equals("Content-Length")) #=MQE  
{ ]:Q7Gys  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); d\cwUXf J  
break; ,0~/ Cn  
} /&+6nOP  
} qM$~5uu  
else Nr#Y]9nA  
break; `tCOe  
} ? }k~>. \  
} yk5T"#'+  
catch(IOException e){e.printStackTrace ();} }UzO_&Z#6  
catch(Exception e){e.printStackTrace ();} <IF\;,.c  
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Utility.log(nFileLength); FZ)Y<r8|s  
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return nFileLength; |sw&sfH[FD  
} ; md{T'  
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//保存下载信息（文件指针位置） F7(~v2|  
private void write_nPos() aDU<wxnSvO  
{ E|iQc8gr&  
try{ F(>Np2oi6  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 1*\o.  
output.writeInt(nStartPos.length); LY%WD%pL  
for(int i=0;i<nStartPos.length;i++) 45@^L's  
{ YtmrRDQs  
// output.writeLong(nPos); GPN]9  
output.writeLong(fileSplitterFetch.nStartPos); e|"WQ>  
output.writeLong(fileSplitterFetch.nEndPos); Y3Yz)T}UkS  
} JRB9rSN^  
output.close(); hgPa
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} ;ub;lh3  
catch(IOException e){e.printStackTrace ();} V<GHpFi0  
catch(Exception e){e.printStackTrace ();} X $jWo@  
} ZOh`(})hy  
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//读取保存的下载信息（文件指针位置） 0XE4<U  
private void read_nPos() eA2@Nkw~)  
{ ofm#'7P 0  
try{ NPy&OcRl  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); bCRV\myd`  
int nCount = input.readInt(); ,E S0NA  
nStartPos = new long[nCount]; C5o#i*|  
nEndPos = new long[nCount]; Y]'Z7<U}*E  
for(int i=0;i<nStartPos.length;i++) Va"0>KX  
{ <^#,_o,!  
nStartPos = input.readLong(); ;U/&I3dzV  
nEndPos = input.readLong(); ag [ZW  
} akp-zn&je  
input.close(); =$'6(aDH  
} :CG`t?N9M  
catch(IOException e){e.printStackTrace ();} ldU?{o:\s  
catch(Exception e){e.printStackTrace ();} 0"<H;7K#W  
} p`olCp'  
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private void processErrorCode(int nErrorCode) 5_GYrR2  
{ {$0mwAOH "  
System.err.println("Error Code : " + nErrorCode); DX#Nf""Pw  
} <cps2*'  
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9  
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//停止文件下载 +}Dw3;W}m  
public void siteStop() xQ7l~O b  
{ |jGf<Bf5  
bStop = true; IaSR;/  
for(int i=0;i<nStartPos.length;i++) <FV1Wz  
fileSplitterFetch.splitterStop(); G#ZH.24Y  
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} =W(Q34  
}  dm\F  
//负责部分文件的抓取 $*^7iT4q_t  
**FileSplitterFetch.java <}C oQz  
*/ '$i: 2mn,  
package NetFox; ?1~`*LE  
9}rS(/@ }  
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import java.io.*; P7
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import java.net.*; p_RsU`[  
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public class FileSplitterFetch extends Thread { g|
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String sURL; //File URL {&&z-^  
long nStartPos; //File Snippet Start Position ?g_3 [Fk  
long nEndPos; //File Snippet End Position ; 5*&xz  
int nThreadID; //Thread's ID 7r6.n61F  
boolean bDownOver = false; //Downing is over j\eI0b @*  
boolean bStop = false; //Stop identical G<L;4nA)  
FileAccessI fileAccessI = null; //File Access interface yuh *  
<$D`Z-6  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException N=V==Dbu-  
{ P\E<9*V  
this.sURL = sURL; ]%;:7?5l  
this.nStartPos = nStart; 9)l$ aBa  
this.nEndPos = nEnd; #|uCgdi  
nThreadID = id; tHU2/V:R  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 U7?;UCmX  
} #]\Uk,mhZB  
^ gdaa>L  
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public void run() tj'\tW+s'  
{ on4HKeO  
while(nStartPos < nEndPos && !bStop) iDpSj!x/_  
{ mVj9,q0  
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try{ /4yo`  
URL url = new URL(sURL); sU=H&D99  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); D(~U6SR  
httpConnection.setRequestProperty("User-Agent","NetFox"); %Tfbsyf%f  
String sProperty = "bytes="+nStartPos+"-"; H%[eV8  
httpConnection.setRequestProperty("RANGE",sProperty); dn&s*  
Utility.log(sProperty); #NQMy:JHD)  
})'B<vq  
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InputStream input = httpConnection.getInputStream(); 0j^Kgx  
//logResponseHead(httpConnection); S;Fi?M  
{B~QQMEow  
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byte[] b = new byte[1024]; ko!)s  
int nRead; R!HXhQ  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop)
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{ 21n?=[  
nStartPos += fileAccessI.write(b,0,nRead); v_yw@  
//if(nThreadID == 1) t$`r4Lb9/  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); @="Pn5<]C  
} F/]2G^-  
 \__i  
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Utility.log("Thread " + nThreadID + " is over!"); :@yEQ#nFp  
bDownOver = true; Jx:Y-$  
//nPos = fileAccessI.write (b,0,nRead); A@`}c,G  
} L7l FtX+b  
catch(Exception e){e.printStackTrace ();} kj Jn2c:y  
} Z*F3G#A  
} ::`HQ@^  
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HVRZ[Y<^  
//打印回应的头信息 s9mx  
public void logResponseHead(HttpURLConnection con) p#-Z4-`  
{ rm7ANMB:  
for(int i=1;;i++) [z:
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{ &0d#Y]D4`  
String header=con.getHeaderFieldKey(i); 9gW|}&-  
if(header!=null) e+EQ]<M  
//responseHeaders.put(header,httpConnection.getHeaderField(header));  8$=n j  
Utility.log(header+" : "+con.getHeaderField(header)); ?d*z8w  
else @@f"%2ZR[  
break; GC-5X`Sq  
} .e#w)K  
} x[p|G5  
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9+|$$)  
public void splitterStop() KM,\  
{ }PlRx6r@  
bStop = true; poE0{HOU  
}
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} (g]!J_Z"  
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/* 9X6h  
**FileAccess.java Ov@gh kr  
*//文件访问(定位，写) }CSDV9).S  
package NetFox;  1~gnc|?  
import java.io.*; l$KA)xbI  
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}RF(CwZr(  
public class FileAccessI implements Serializable{ 70?\ugxA  
-_g0C^:<,  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 8S TvCH"Z_  
RandomAccessFile oSavedFile; "x0^#AVg  
long nPos; b/K PaNv  
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public FileAccessI() throws IOException &u."A3(  
{ `7E;VL^Y1  
this("",0); T=DbBy0-  
} %@b0[ZC  
h,:m~0gmj  
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public FileAccessI(String sName,long nPos) throws IOException LENq_@$  
{ bIDj[-CDG  
oSavedFile = new RandomAccessFile(sName,"rw"); P}}* Q7P  
this.nPos = nPos; l:~/<`o  
oSavedFile.seek(nPos); J3V= 46Yc  
} fUWG*o9  
ELoDd&d8  
!/b>sN}  
public synchronized int write(byte[] b,int nStart,int nLen) n`_{9R  
{ ,&A7iO  
int n = -1; dl)Y'DI  
try{ [\eeDa  
oSavedFile.write(b,nStart,nLen); Z?q]bSIT  
n = nLen; C}j"Qi`  
} N{!i
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catch(IOException e) {lzWrUGO  
{ UW={[h{.|@  
e.printStackTrace (); QE+g j8  
} /KaZH
R.  
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return n; x;.Jw6g  
} 9.M4o[  
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} ?=msH=N<l  
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/* q[_VuA]&  
**SiteInfoBean.java oH?b}T=9jz  
*/ xj)F55e?  
package NetFox; HyQJXw?A:  
O/(`S<iip  
]jQutlg|  
public class SiteInfoBean { x8B}ZIbT9  
C==hox7b  
net@j#}j-  
private String sSiteURL; //Site's URL
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private String sFilePath; //Saved File's Path Xu'&ynID  
private String sFileName; //Saved File's Name 8FK/~,I  
private int nSplitter; //Count of Splited Downloading File P`+{@@  
H2 {+)  
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public SiteInfoBean() x_}:D *aI  
{//nSplitter的缺省值为5 Mj3A5;#  
//default value of nSplitter is 5 +)om^e@.  
this("","","",5);  qA7>vi%  
} k"%~"9  
K7B/s9/xs  
RLXL&  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ,-LwtePJ0  
{ +o{R _  
sSiteURL= sURL; Q8tL[>Xt  
sFilePath = sPath; >>
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sFileName = sName; O63<AY@  
this.nSplitter = nSpiltter;
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)EuvRLo{S7  
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} ^/>(6>S^M  
x+:UN'
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public String getSSiteURL() #G|RnV%t$~  
{ [b%D3-}'  
return sSiteURL; >8^ $ [}w  
} X7MM2V  
bo>*fNqAIy  
4B1v4g8}  
public void setSSiteURL(String value) 65P0,b6"OT  
{ nnEgx;Nl0  
sSiteURL = value; y2dCEmhY  
} D/xbF`  
2WL|wwA  
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public String getSFilePath() 7IH@oMvE  
{ (N6i4 g6  
return sFilePath; V7Lxfoa4  
} 7kLz[N6Ll  
[PM2\#K  
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public void setSFilePath(String value) jD]~ AwRJ  
{ 6I4\q.^qw  
sFilePath = value; IqHV)A  
} x"=f+Mr  
wk D^r(hiH  
r'r%w#=`t  
public String getSFileName() :{v#'U/^  
{ 4jMFr,  
return sFileName; 6:5I26  
} (zYtNLoFx  
{X+3;&@  
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public void setSFileName(String value) %P/Jq#FE.  
{ S(lO(gY  
sFileName = value; )p0^zv{  
} l`{\"#4  
=`F(B  
]=I@1B;_m  
public int getNSplitter() +F` S>U  
{ #e1>H1eU  
return nSplitter; z&)A,ryW0  
} (!aNq(   
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drP=A~?&:  
public void setNSplitter(int nCount) X*XZb F"=  
{ KnQ*vM*VM  
nSplitter = nCount; Jy:
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} gQg"j)  
} o Q2Fjj  
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/* e0zq1XcZ  
**Utility.java wLH>:yKUU  
*/ ~O0 $Suv  
package NetFox; y/{fX(aV  
wC+u73599  
*[Tz![|  
public class Utility { ->-KCd1b  
H3^},.  
W=><)miQ@  
public Utility() @7]yl&LZ  
{ oy=js -  
w^|*m/h|@u  
!4RWYMV"  
} Gbr=+AT  
,t?B+$E  
//线程睡眠 k8[n+^  
public static void sleep(int nSecond) mbxZL<ua  
{ C.yQ=\U2  
try{ HGs $*  
Thread.sleep(nSecond); b\kdKVh&  
} D6Ui!  
catch(Exception e) ColV8oVnU  
{ TH&U j1  
e.printStackTrace (); _Xc8Yg }`  
} :Zbg9`d*  
} jh%Eq+#S  
x(6SG+Kr  
//日志 KNvZm;Q6  
public static void log(String sMsg) A@[o;H}XP  
{ @ $ ;q;  
System.err.println(sMsg); ]d0BN`*U.  
} ^R7lom.  
]Idk:et  
:'-/NtV)o?  
public static void log(int sMsg) gjwn7_  
{ ^e_hLX\SW  
System.err.println(sMsg); x7&B$.>3  
} wr/"yQA]  
} qZtzO2Mt  
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v!6  c0a  
/* P6-s0]-g  
**TestMethod.java DS(}<HK{  
*/ 8B K(4?gC  
package NetFox; qFCOUl  
xw,IJ/E$1  
.+3g*Dv{&  
public class TestMethod { ?W?c1>  
df4A RP+  
F2LLN  
public TestMethod() :Uzm  
{ ///xx/weblogic60b2_win.exe M
#4pE_G  
try{ 30#s aGV  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); /tx]5`#@7]  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); TOB-aAO  
SiteFileFetch fileFetch = new SiteFileFetch(bean); }%ojw |  
fileFetch.start(); nLZTK&7}  
} pk$l+sNZ=  
catch(Exception e){e.printStackTrace ();} SumF 2  
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~S"+S/z/k  
} ifMRryN4  
2/\r)$ 2i  
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public static void main(String[] args) ~F|+o}a`  
{ y1eWpPJa  
new TestMethod(); 3</_c1~  
} [2!w_Iw'  
} ) <[XtK  
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