http断点续传简单实现（java)

/* x bsk  
**SiteFileFetch.java YaWZOuxm  
*/ 2c Pd$j  
package NetFox; @Z fQ)q\  
import java.io.*; 7 B<  
import java.net.*; 7tEkQZMDI  
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public class SiteFileFetch extends Thread { Uh9p,AV  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ;nDCyn4i]  
long[] nStartPos; //开始位置 C}= *%S  
long[] nEndPos; //结束位置 R;6$lO8C&  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 S>! YBzm&X  
long nFileLength; //文件长度 %O=U|tuc$  
boolean bFirst = true; //是否第一次取文件 G(n e8L8  
boolean bStop = false; //停止标志 6w )mo)<X  
File tmpFile; //文件下载的临时信息 3.c0PRZ  
DataOutputStream output; //输出到文件的输出流 nNN~Z'bG  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） </.9QV  
public SiteFileFetch(SiteInfoBean bean) throws IOException h}T+M BA%  
{ )
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siteInfoBean = bean; ^~iFG+g5  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Zs$Qo->F  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); W$I^Ej}>$  
if(tmpFile.exists ()) #jc+2F,+{  
{ !zu YO3:  
bFirst = false; NFVr$?P  
read_nPos(); 3y[uH'  
} efc<lSUR  
else  .IO_&^  
{ y4V~fg;  
nStartPos = new long[bean.getNSplitter()]; 8RA]h?$$J  
nEndPos = new long[bean.getNSplitter()]; n]15 ~GO.  
} ];3]/b)&  
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} K4r"Q*h  
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public void run() _SW_I{fjr  
{ 6>fQe8Y  
//获得文件长度 y7x&/2  
//分割文件 $N}nO:`t  
//实例FileSplitterFetch DX*eN"z[  
//启动FileSplitterFetch线程 ! H^,p$`[i  
//等待子线程返回 <hJ%]]  
try{ 2 SJN;A~}  
if(bFirst) &=KNKE`  
{ r Ljb'\<*  
nFileLength = getFileSize(); k3 YDnMRA9  
if(nFileLength == -1) *om
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{ {mkD{2)KQ  
System.err.println("File Length is not known!"); "-WEUz  
} %u)niY-g
 
else if(nFileLength == -2) !"G|y4O  
{ cLZaQsS%  
System.err.println("File is not access!"); l2&s4ERqSm  
} T>!Y-e.q  
else daX$=n  
{ bg =<)s  
for(int i=0;i<nStartPos.length;i++) MnQ4,+ji-  
{ k|r+/gIV  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); fFSQLtm?E  
} Z [aKic  
for(int i=0;i<nEndPos.length-1;i++) pZ IDGy=~  
{ 3YFbT Z  
nEndPos = nStartPos[i+1]; ^z _m<&r  
} #},4m  
nEndPos[nEndPos.length-1] = nFileLength; kT=KxS{  
} 1luRTI8^  
} }Qqi013E L  
&>YdX$8x  
;P
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//启动子线程 [yEH!7  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; (FY<%.Pa  
for(int i=0;i<nStartPos.length;i++) R9!GDKts%  
{ @[s+5_9nk  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Yp;6.\Z8[  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Z ZMz0^V  
nStartPos,nEndPos,i); I?z*.yA*  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); GY3g`M   
fileSplitterFetch.start(); ZQVr]/W^r  
} o)M=; !  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), /`2t$71)  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); |)4aIa  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", pE~>k:  
nEndPos = " + nFileLength); ,WA[HwY-  
// fileSplitterFetch[nPos.length-1].start(); hd'JXKMy  
WlF}R\N!  
T\ cJn>kCn  
//等待子线程结束 -!ARVf *  
//int count = 0; Q&@~<!t  
//是否结束while循环 PlX6,3F  
boolean breakWhile = false; Wifr%&t{J  
2H]~X9,z2  
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while(!bStop) `yvH0B -  
{ 3lw8%QD>  
write_nPos(); Vt[Kr  
Utility.sleep(500); ,t!K? Y  
breakWhile = true; :mI[fQ  
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for(int i=0;i<nStartPos.length;i++) (9A`[TRwi  
{ k/`WfSM\.  
if(!fileSplitterFetch.bDownOver) |#Q4e51H  
{ - / tzt  
breakWhile = false; PIthv[F  
break; ]rY3bG'&  
} SBbPO5^](  
} 4_i6qu(4  
if(breakWhile) O\5q_>]  
break; pn._u`xMV  
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//count++; Y;B#_}yF  
//if(count>4) :VvJx]  
// siteStop(); hj*Fn  
} N =0R6{'  
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System.err.println("文件下载结束！"); wvuh   
} )h&*b9[B=  
catch(Exception e){e.printStackTrace ();} mz<wYV*  
} ZBf9Upg  
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//获得文件长度 sO;]l"{<  
public long getFileSize() 5"cYZvGkJ  
{ OBBEsD/bc  
int nFileLength = -1; C\d5t4s  
try{ ~p'DPg4  
URL url = new URL(siteInfoBean.getSSiteURL()); J]=2] oI2  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); w*-1*XNA  
httpConnection.setRequestProperty("User-Agent","NetFox"); puPYM"  
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int responseCode=httpConnection.getResponseCode(); DdG*eKC  
if(responseCode>=400) ROfr  
{ w*3DIVlxL  
processErrorCode(responseCode); cz6\qSh\,  
return -2; //-2 represent access is error I$#)k^
Q  
} /[|ODfY
 
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String sHeader; ~?x `f+  
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for(int i=1;;i++) AWqc?K@   
{ *\5o0~~8J  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); U}]uPvu  
//Utility.log(in.readLine()); q&y9(ZvI  
sHeader=httpConnection.getHeaderFieldKey(i); 0u7\*Iy  
if(sHeader!=null) :: 2pDtMS  
{ )b_ GKA `  
if(sHeader.equals("Content-Length")) ::Nhs/B/  
{ 7Hm/g  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); `Y5{opG7-  
break; a|s64+  
} HNj6Iw  
} 3|FZ!8D  
else z$q:Yg  
break; $kM8E@x2  
} uSRvc0R\  
} 'J=knjAT  
catch(IOException e){e.printStackTrace ();} CaV>\E)  
catch(Exception e){e.printStackTrace ();} .!&S{;Vv?W  
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Utility.log(nFileLength); Wz^M*=,  
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return nFileLength; e[8AdE  
} w'-J24>=  
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J% t[{  
//保存下载信息（文件指针位置） , 7kS#`P  
private void write_nPos() \;%DDw  
{ UFED*al#  
try{ !UV/p"CfX  
output = new DataOutputStream(new FileOutputStream(tmpFile)); )&$Zt(  
output.writeInt(nStartPos.length); " ~X;u8m  
for(int i=0;i<nStartPos.length;i++) vMQvq9T}  
{ >10pk  
// output.writeLong(nPos); .vbUv3NI  
output.writeLong(fileSplitterFetch.nStartPos); p7YfOUo k  
output.writeLong(fileSplitterFetch.nEndPos); 51\N+  
} ]("5O V5  
output.close(); Q6r!=yOEY  
} OGjeE4  
catch(IOException e){e.printStackTrace ();} )ZI9n7  
catch(Exception e){e.printStackTrace ();} r,`59  
} @Q=P6Rz {S  
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//读取保存的下载信息（文件指针位置） q|[P[7z  
private void read_nPos() %](H?'H  
{ _%`<V!RT\  
try{ o=,q4;R'  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 5>e3srKu  
int nCount = input.readInt(); Dn#GoDMJ[  
nStartPos = new long[nCount]; Fk 5;  
nEndPos = new long[nCount]; U/|H%b  
for(int i=0;i<nStartPos.length;i++) u7Xr!d+wR  
{ #78P_{#!  
nStartPos = input.readLong(); s|1BqoE  
nEndPos = input.readLong(); k$hNibpkt  
} Nd"Rt  
input.close(); gmY*}d` 'f  
} p=U/l#xO  
catch(IOException e){e.printStackTrace ();} VS:UVe  
catch(Exception e){e.printStackTrace ();} cVR3_e{&H  
} =>0+BD  
#]@<YKoV{  
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private void processErrorCode(int nErrorCode) V`n;W6Q17  
{ -UPl
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System.err.println("Error Code : " + nErrorCode); 3]X9 z  
} Jhyb{i8RR  
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,a$?KX  
//停止文件下载 kUdl2["MZ  
public void siteStop() A!K/92[#@  
{ 5G\CT&cQR  
bStop = true; (j%d{y4  
for(int i=0;i<nStartPos.length;i++) wlh V!a0>  
fileSplitterFetch.splitterStop(); Tu'/XUs;k  
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} 1Ugyjjlz  
} 4RH'G
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//负责部分文件的抓取 eDm~B(G$  
**FileSplitterFetch.java Z(8'ki  
*/ =!G3YZ  
package NetFox; >tq,F"2amC  
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import java.io.*; %("Bq"Q8  
import java.net.*; NjCdkT&g  
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public class FileSplitterFetch extends Thread { ;9{x""
 
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String sURL; //File URL ">n38:?R  
long nStartPos; //File Snippet Start Position [U]ouh)  
long nEndPos; //File Snippet End Position nC3U%*l  
int nThreadID; //Thread's ID uh~/ybR  
boolean bDownOver = false; //Downing is over P~)ndaQ  
boolean bStop = false; //Stop identical <&?gpRK  
FileAccessI fileAccessI = null; //File Access interface Y}bJN%M  
`>1"v9eF
 
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 2 NgEzY5  
{ LWB"}#vt  
this.sURL = sURL; M1MpR+7S  
this.nStartPos = nStart; 5pBQ~m3  
this.nEndPos = nEnd; <(]e/}  
nThreadID = id; w>IYrSaa>  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 FT1h\K|a  
} b[^=GF>e  
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public void run() *nB fF{y  
{ m[7i<'+S  
while(nStartPos < nEndPos && !bStop) IeqJ>t:  
{ q
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) #/@Jo2F  
try{ |kwkikGQS  
URL url = new URL(sURL); qzVmsxBNP  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); y&0&K4aa  
httpConnection.setRequestProperty("User-Agent","NetFox"); uA?_\z?  
String sProperty = "bytes="+nStartPos+"-"; #rZk&q  
httpConnection.setRequestProperty("RANGE",sProperty); Tr1#=&N0  
Utility.log(sProperty); yqF$J"=|  
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InputStream input = httpConnection.getInputStream(); zX-6]j;  
//logResponseHead(httpConnection); S8O^^jJq;  
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s  
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byte[] b = new byte[1024]; g8yWFqE!T  
int nRead; `A.!<bO)]  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) <}RU37,W  
{ 5#zwdoQ  
nStartPos += fileAccessI.write(b,0,nRead); g1Q^x/  
//if(nThreadID == 1) J?XEF@?'G  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Ve,_;<F]S  
} 1NO<K`  
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Utility.log("Thread " + nThreadID + " is over!"); H!Y`?Rc  
bDownOver = true; *'+OA
6  
//nPos = fileAccessI.write (b,0,nRead); Gd)@PWK  
} BJ3st  
catch(Exception e){e.printStackTrace ();} 29K09 0f  
} D?rQQxb  
} R>"E Xq  
" }@QL`  
z.
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//打印回应的头信息 :\Z;FA@g(g  
public void logResponseHead(HttpURLConnection con) .`!|^h%0  
{ C#X0Cn0ln  
for(int i=1;;i++) A2z%zMlZc  
{ B.&ly/d  
String header=con.getHeaderFieldKey(i); W:uIG-y~  
if(header!=null) v7O
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); $;%-<*C
o  
Utility.log(header+" : "+con.getHeaderField(header)); Ga-AhP  
else "Hmo`EB0  
break; NDhHU#Q9  
} Wig
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} >JFAE5tj&2  
^f{+p*i}:  
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public void splitterStop() nX<!n\J T  
{ dx}()i\@  
bStop = true; 2pH2s\r<UJ  
} 3Z NYR'  
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} e`'O!  
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/* VR2BdfKU,  
**FileAccess.java ,\4@Ao  
*//文件访问(定位，写) \TkBV?W  
package NetFox; m!a<\0^  
import java.io.*; W @Y$!V<  
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public class FileAccessI implements Serializable{ ;+>-uPT/1  
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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 y&-wb'==p  
RandomAccessFile oSavedFile; 3Ew-Ia%A  
long nPos; _}:9ic]e  
;hA>?o_i(  
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public FileAccessI() throws IOException E)H: L-  
{ (Gf1#,/3~  
this("",0); vg&Dr  
} 5rRYv~+  
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k
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public FileAccessI(String sName,long nPos) throws IOException #WwQ^6ESc  
{ }o0R`15dA  
oSavedFile = new RandomAccessFile(sName,"rw"); j#$ R.  
this.nPos = nPos; tH,}_Bp  
oSavedFile.seek(nPos); zGHP{a1O7  
} KFCrJ)  
U=\ZeYK.  
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public synchronized int write(byte[] b,int nStart,int nLen) c}kZx1  
{ SL zL/5s  
int n = -1; r03
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try{ xgn@1.}G  
oSavedFile.write(b,nStart,nLen); 6Db1mvSe  
n = nLen; $YSAD\a<  
} (zIP@ H  
catch(IOException e) [wWip1OR  
{ `of 5h*k  
e.printStackTrace (); =hxj B*")  
} ~McmlJzJG  
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return n; TCYjj:/  
} 3%{A"^S=}
 
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} OJPxV~y  
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~B;kFdcVXn  
/* )XV|D  
**SiteInfoBean.java |Wd]:ijJ  
*/ izy7.(.a  
package NetFox; h[b5"Uqj  
bO]^TRai
J  
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public class SiteInfoBean { qgg/_H:;w  
nd*9vxM  
23?\jw3w  
private String sSiteURL; //Site's URL T4dLuJl  
private String sFilePath; //Saved File's Path k FE2Vv4.  
private String sFileName; //Saved File's Name uCO-f<b  
private int nSplitter; //Count of Splited Downloading File <aR9,:  
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public SiteInfoBean() Z 6KM%R  
{//nSplitter的缺省值为5 GjN/8>/  
//default value of nSplitter is 5 R_ymTB}<t(  
this("","","",5); ^ cpQ*Fz  
} s kC*  
#Jp_y|  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Zz}Wg@&  
{ *@/1]W  
sSiteURL= sURL; <wWZ]P2]  
sFilePath = sPath; nt.A X  
sFileName = sName; &?UIe]  
this.nSplitter = nSpiltter; -x)Oo`  
Xu\FcQ{  
12qX[39/  
} lx_jy>$}r  
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{:BAh5e|  
public String getSSiteURL() Y'7f"W  
{ lVF}G[B  
return sSiteURL; "#1KO1@G  
} V'?bZcRr~  
*`$Y!uzG:\  
]S
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public void setSSiteURL(String value) dS]TTU1
 
{ ,l/~epx4v)  
sSiteURL = value; hG51jVYtw  
} Lc4\i  
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public String getSFilePath() g(Q
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{ q2 K@i*s  
return sFilePath; dd1CuOd6(1  
} KG
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public void setSFilePath(String value) '-C%?*ku  
{ vF yl,S5A  
sFilePath = value; c1 aCN  
} "Kky|(EQ$$  
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v"wxHro  
public String getSFileName() &j=FxF9o  
{ n7-|\p!xP6  
return sFileName; z H$^.1  
} )H=}bqn  
8T"C]  
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public void setSFileName(String value) tg =ClZ-  
{ Y'K+O  
sFileName = value; t8SvU  
} ]^aOYtKX  
/zxLnT; 5  
}nh!dVA8lh  
public int getNSplitter() UQ]W
BS\  
{ 6zv-nMZc  
return nSplitter; 6&,n\EXF  
} me-Tv7WL  
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public void setNSplitter(int nCount)  l Ozi|  
{ zgre&BV0q  
nSplitter = nCount; obA}SF  
} Cka
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} bu[PQsT  
0zJT_H+  
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/* +c4-7/kE  
**Utility.java q8&2
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*/ j"G1D-S:  
package NetFox; 2cv!85  
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public class Utility { ":=\ci]e%  
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(41BUX  
public Utility() bEO\oS  
{ B$ty`/{w,B  
i/Zv@GF  
vbFi#|EU  
} yC%zX}5  
w=e_@^Fkx  
//线程睡眠 w5/`_m!  
public static void sleep(int nSecond) t<8vgdD  
{ Oz8"s4Y7  
try{ Z8vMVo  
Thread.sleep(nSecond); Ug :3)q[O  
} _FpZc?=  
catch(Exception e) 8+}yf.`  
{ RbOEXH*]  
e.printStackTrace (); cV;<!f+  
} VTS7K2lBvX  
} y$i^C:N  
0)<\jo1 F  
//日志 `O5 Hzb(}  
public static void log(String sMsg) p2m@0ou  
{ ?E>(zV1D/  
System.err.println(sMsg); C8^h`B9z&I  
} FYwMmb ~3  

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public static void log(int sMsg) \xCI8 *W  
{ ?=u/&3Cw  
System.err.println(sMsg); JAt$WW{  
} Rs$fNW@P  
} e6G=Bq$  
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c>SFttbU  
/* 5Z8Zb.  
**TestMethod.java +qPpPjG;  
*/ ,\){-H/n  
package NetFox; J#1-Le8@  
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Bqcih$`BVU  
public class TestMethod { cd&^ vQL8  
ON,sN  
z (1zth  
public TestMethod() #'5C*RO  
{ ///xx/weblogic60b2_win.exe 9+irf^D`O  
try{ OBnf5*eJ  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); !xE/  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); X  jPPgI  
SiteFileFetch fileFetch = new SiteFileFetch(bean); J\@ r~x5G  
fileFetch.start(); \*a7o GyH>  
} E=*82Y=B  
catch(Exception e){e.printStackTrace ();} xX !`0T7Y  
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kv!QO^;^Y  
} w
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f6of8BOg  
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public static void main(String[] args) ^uWPbW&/q  
{ Os90fR  
new TestMethod(); kA.U2  
} (&Kv]
--  
} hSN{jl{L`  
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