http断点续传简单实现（java)

/* 2Z20E$Cb
 
**SiteFileFetch.java f|u#2
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*/ 7JSNYTH  
package NetFox; iNwqF0  
import java.io.*; FI"`DMb}  
import java.net.*; s1?[7yC  
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public class SiteFileFetch extends Thread { mSk5u7  
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SiteInfoBean siteInfoBean = null; //文件信息Bean xkOpa,=FI  
long[] nStartPos; //开始位置 y4+;z2'>  
long[] nEndPos; //结束位置 RpLE 02U  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 L
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long nFileLength; //文件长度 e.c3nKXZ q  
boolean bFirst = true; //是否第一次取文件 j5@:a  
boolean bStop = false; //停止标志 W2uOR{ '?  
File tmpFile; //文件下载的临时信息 :!zl^J;  
DataOutputStream output; //输出到文件的输出流 5q"ON)x  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） _)]CzBRq\6  
public SiteFileFetch(SiteInfoBean bean) throws IOException !x'/9^i~v  
{ |lv|!]qAma  
siteInfoBean = bean; XD"_Iq!  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); d#2$!z#  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ')GSAY7  
if(tmpFile.exists ()) 'l,V*5L  
{ u^029sH6j  
bFirst = false; d;n."+=[x  
read_nPos(); a~8[<Fomj  
} a#T]*(Yq)  
else Nan
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{ d\|!Hg,  
nStartPos = new long[bean.getNSplitter()]; %e&9.  
nEndPos = new long[bean.getNSplitter()]; y^o@"IYu3  
} v9T_
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} s`>[F@N7.o  
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public void run() Rb
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{ u+{a8=  
//获得文件长度 i1RiGS
 
//分割文件 }jill+]  
//实例FileSplitterFetch A=Ss6-Je  
//启动FileSplitterFetch线程 ^_lzZOhG  
//等待子线程返回 |F#1C9]P  
try{ )Wb0u0)_  
if(bFirst) 5Enotp[  
{ Ie%EH  
nFileLength = getFileSize(); /r_~:3F  
if(nFileLength == -1) H.UX,O@  
{ n("0%@ov  
System.err.println("File Length is not known!"); " LJq%E  
} XkyKBg-  
else if(nFileLength == -2) n@G[  
{ >ooZj9:'  
System.err.println("File is not access!"); qTQBt}  
} Z(!00^  
else yv)ux:P&+  
{ sN5B7)Vc  
for(int i=0;i<nStartPos.length;i++) CW<N: F.9  
{ *}8t{ F@k  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); W0}B'VS.I  
} qoAj] ")  
for(int i=0;i<nEndPos.length-1;i++) c_elShK8#  
{ \rPbK+G.  
nEndPos = nStartPos[i+1]; O(_[ayE  
} |hr]>P1  
nEndPos[nEndPos.length-1] = nFileLength; (e"iO`H  
} ^n+!4(@=  
} *YlV-C<}W"  
>$2V%};  
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//启动子线程 S
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ^i:B+ rl  
for(int i=0;i<nStartPos.length;i++) hdVdcnM  
{ (dv]=5""  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Qqlup  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ":_vK}5  
nStartPos,nEndPos,i); 2=_gf  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); f47M#UC  
fileSplitterFetch.start(); zhf.NCSt(  
} R"K#7{p9  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), GaSPJt   
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); c*@G_rb  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 8n>9;D5n  
nEndPos = " + nFileLength); +5XpzZ{#Wa  
// fileSplitterFetch[nPos.length-1].start(); /B}lO0]:  
Z> r^SWL  
^+g$iM[`f  
//等待子线程结束 jRL<JZ1N  
//int count = 0; H#ncM~y*  
//是否结束while循环 L5,NP5RC  
boolean breakWhile = false; 5ls6t{Ci  
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while(!bStop) H<3I 5Kgt  
{ 9V5-
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write_nPos(); ooQQ-?"m  
Utility.sleep(500); :>=\.\  
breakWhile = true; Q1+dCCY#F  
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for(int i=0;i<nStartPos.length;i++) O?|gp<
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{ /i77  
if(!fileSplitterFetch.bDownOver) #f+$Ddg*  
{ =kuMWaD  
breakWhile = false; QqU!Najf  
break; [KxF'mz9  
} C9t4#"  
} 7a~X:#  
if(breakWhile) SCz318n  
break; KRA/MQ^7~U  
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rOVVL%@QqJ  
//count++; [1u-Q%?#  
//if(count>4) Ih"XV  
// siteStop(); cCxBzkH6  
} p3^m9J  
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}+sT4'Ah>  
System.err.println("文件下载结束！"); F|!){=   
} 1@-Ns  
catch(Exception e){e.printStackTrace ();} \P6$mh\T  
} L+i(TM=  
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//获得文件长度 LSRk7'0  
public long getFileSize() o !U 6?  
{ =y!$/(H  
int nFileLength = -1; g pOC`=  
try{ ){b@}13cF  
URL url = new URL(siteInfoBean.getSSiteURL()); HZ:6zH  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); \*<d{gZ~  
httpConnection.setRequestProperty("User-Agent","NetFox"); &oX>*6L  
^cuc.g)c$?  
)h)]SF}  
int responseCode=httpConnection.getResponseCode(); (}2~<   
if(responseCode>=400) % S os  
{ .*
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processErrorCode(responseCode); a8UwhjFO  
return -2; //-2 represent access is error 7K98#;a)5  
} zl
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String sHeader; mVpMh#zw  
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for(int i=1;;i++) {.INnFGP@)  
{ nX`u[ks  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ]@u6HH~^  
//Utility.log(in.readLine()); +csi[c)3E  
sHeader=httpConnection.getHeaderFieldKey(i); #%h-[/  
if(sHeader!=null) h3xAJ!  
{ *vwbgJG! *  
if(sHeader.equals("Content-Length")) 73\JwOn~  
{ &eX!#nQ_.  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); R)m'lMi|  
break; \r+8qC[,  
} +O?KNZ  
} 7](
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else ~o~!+`@q  
break; pWJFz-  
} V: TM]  
} <d$x.in  
catch(IOException e){e.printStackTrace ();} XcUwr  
catch(Exception e){e.printStackTrace ();} O*FUTZd(J  
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}WH&iES@P  
Utility.log(nFileLength); &n8_0|gK  
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return nFileLength; ~ r438&  
} 
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//保存下载信息（文件指针位置） >E{";C)  
private void write_nPos() 7Bd-!$j+  
{ KJaXg;,H  
try{ wMg0>  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 8b;1FQ'  
output.writeInt(nStartPos.length); f@
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for(int i=0;i<nStartPos.length;i++) 6"&6`f  
{ "ozr+:#\  
// output.writeLong(nPos); c2'Lfgx4  
output.writeLong(fileSplitterFetch.nStartPos); #W.#Hjpp  
output.writeLong(fileSplitterFetch.nEndPos); 2Tp1n8FV  
} U!*M*s  
output.close(); Xx0hc 8qd  
} U"^kH|  
catch(IOException e){e.printStackTrace ();} #PH~1`vl  
catch(Exception e){e.printStackTrace ();} lHPd"3HDK  
} f\sQO&  
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//读取保存的下载信息（文件指针位置） g'n7T|h ~  
private void read_nPos() 9\mLW"  
{ Vg>dI&O  
try{ ]rH\`0  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); QLiu2U o  
int nCount = input.readInt(); 8y.wSu  
nStartPos = new long[nCount]; gf &Pn  
nEndPos = new long[nCount]; B][U4WJ)  
for(int i=0;i<nStartPos.length;i++) |Sy<@oq  
{ VyXhl;  
nStartPos = input.readLong(); fY51:0{  
nEndPos = input.readLong(); ?IqQ-C)6D  
} OuID%p"O  
input.close(); Y4`}y-'d  
} Tz8PSk1[  
catch(IOException e){e.printStackTrace ();} 2q=AEv/  
catch(Exception e){e.printStackTrace ();} PGhY>$q>b  
} <oT^A|JFj  
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private void processErrorCode(int nErrorCode) 8m\7*l^D:  
{ L\xk:j1[  
System.err.println("Error Code : " + nErrorCode); Ez fN&8E  
} vyK7I%T'R  
(3Two}  
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//停止文件下载 $j5K8Ad  
public void siteStop() emqZztccZ  
{ ^6MU 0Q2  
bStop = true; p'*>vk  
for(int i=0;i<nStartPos.length;i++) G\Cp7:j}  
fileSplitterFetch.splitterStop(); vgH3<pDiU6  
mGJKvJF   
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} (a.z9nqGA  
} w[zjerH3  
//负责部分文件的抓取 75f"'nJ)  
**FileSplitterFetch.java diL+:H  
*/ 1{ ~#H<K  
package NetFox; p.v0D:@&  
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import java.io.*; "55skmD.P  
import java.net.*; RI 5yF  
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public class FileSplitterFetch extends Thread { vNV/eB8#S  
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String sURL; //File URL fk6%XO  
long nStartPos; //File Snippet Start Position A+ZK4]xb  
long nEndPos; //File Snippet End Position la0BiLzb]  
int nThreadID; //Thread's ID &:9cAIe]H  
boolean bDownOver = false; //Downing is over =.f-w0V  
boolean bStop = false; //Stop identical ;c-(ObSm  
FileAccessI fileAccessI = null; //File Access interface K6v6ynp/  
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7~^GA.92  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 9kN}c
<o  
{ B(LWdap~  
this.sURL = sURL; ~:kZgUP_f  
this.nStartPos = nStart; 42{Ew8  
this.nEndPos = nEnd; mZtCL  
nThreadID = id; #%iDT6  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 eL10Q(;P`  
} 3G,Oba[$<  
8uc1iB  
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public void run() tZ:_ag)o  
{ ^ =bu(L  
while(nStartPos < nEndPos && !bStop) fi-WZ  
{ a oD`=I*<  
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try{ q0i(
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URL url = new URL(sURL); [,t*Pfq'W8  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); gPNZF\ r  
httpConnection.setRequestProperty("User-Agent","NetFox"); (6?9BlH~  
String sProperty = "bytes="+nStartPos+"-"; q>_/u"  
httpConnection.setRequestProperty("RANGE",sProperty); R} eN@#"D  
Utility.log(sProperty); kO.%9wFbz  
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InputStream input = httpConnection.getInputStream(); YSr9VpqWV  
//logResponseHead(httpConnection); Xb:;</  
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byte[] b = new byte[1024]; f=(?JT  
int nRead; ][gq#Vx@  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 3GaQk-  
{ 5,3'=mA6  
nStartPos += fileAccessI.write(b,0,nRead); "Gfh,e  
//if(nThreadID == 1) q+H%)kF  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 6]V4muz#c  
} 8##-EN;ag  
#a/5SZP Z\  
8{wwd:6  
Utility.log("Thread " + nThreadID + " is over!"); 9oRy)_5Z(=  
bDownOver = true; /[a~3^Gs^  
//nPos = fileAccessI.write (b,0,nRead); Tzt8h\Q^z  
} -[*,^Ti`  
catch(Exception e){e.printStackTrace ();} c(3~0Yr  
} &oP+$;Y  
} 3EV;LH L  
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CY 4gSe?  
//打印回应的头信息 R@58*c:U(  
public void logResponseHead(HttpURLConnection con) $:=A'd2  
{ 7]U"Z*  
for(int i=1;;i++) h;C5hU4P  
{ 35Ij ..z0  
String header=con.getHeaderFieldKey(i); 54gBJEhg  
if(header!=null) $*^kY
;  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ?Nup1!D  
Utility.log(header+" : "+con.getHeaderField(header)); 2KB\1&N  
else !*s?B L  
break; H
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} `>7;!  
} chcbd y>C  
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public void splitterStop() 6CV* Z\b  
{ |jQ:~2U|  
bStop = true; =}lh_  
} 3AHlSX  
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} sd,J3  
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/* K{x\4  
**FileAccess.java g-Mj.owu=  
*//文件访问(定位，写) X>1,!I9  
package NetFox; sT !~J4  
import java.io.*; 3VsW@SG7N  
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public class FileAccessI implements Serializable{ 9E
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j
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Hc!  mB  
RandomAccessFile oSavedFile; 
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long nPos; J4QXz[dG  
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public FileAccessI() throws IOException H2&@shOOQJ  
{ LM$W*  
this("",0); I(]}XZq  
} G^~k)6v=m  
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public FileAccessI(String sName,long nPos) throws IOException aUzBV\Yd}  
{ MC?,UDNd%  
oSavedFile = new RandomAccessFile(sName,"rw"); w:%o?pKet1  
this.nPos = nPos; iWRH{mK  
oSavedFile.seek(nPos); H(R1o~  
} I CZ4A{I  
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public synchronized int write(byte[] b,int nStart,int nLen) UM!ENI|  
{ VbJiZw(aR  
int n = -1; CUO+9X-<8  
try{ EqyeJq .  
oSavedFile.write(b,nStart,nLen); K-e9>fmB#  
n = nLen; sc|_Q/`\.  
} o]+z)5zC  
catch(IOException e) 3[\iQ*d }B  
{ J{l1nHQZSu  
e.printStackTrace (); 8B7cBkl:  
} +vYoB$!  
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return n; c]$i\i#  
} qHsUP;7  
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} us;YV<)d  
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/* pA`+hQNN  
**SiteInfoBean.java nA?`BOe(  
*/ hhSy0  
package NetFox; X
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public class SiteInfoBean { &K[_J  
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private String sSiteURL; //Site's URL _,zA ^*b  
private String sFilePath; //Saved File's Path YsG%6&zEq  
private String sFileName; //Saved File's Name sC27F
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private int nSplitter; //Count of Splited Downloading File ;>506jZ  
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public SiteInfoBean() z3`-plE  
{//nSplitter的缺省值为5 Wc,_RN-  
//default value of nSplitter is 5 *7*lE"$p  
this("","","",5); y#>,+a#5  
} nnCGg+l  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) bsuus R9W  
{ FjK3 .>'  
sSiteURL= sURL; 0T@Zb={  
sFilePath = sPath; ]P#XVDn+;  
sFileName = sName; H70LhN  
this.nSplitter = nSpiltter; E>&n.%  
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}  gG uZ8:f  
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public String getSSiteURL() k xP-,MD  
{ uJOJ-5}yt  
return sSiteURL; (H)2s Y  
} 4 d;|sI@  
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public void setSSiteURL(String value) I{ HN67O  
{ aki_RG>U'  
sSiteURL = value; HKF H/eV  
} Kpb#K[(]&  
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public String getSFilePath() Q&MZN);.  
{ 0*%Z's\M"  
return sFilePath; iDMJicW!+F  
} :r%P.60H X  
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public void setSFilePath(String value) W"):-Wq  
{ !O-T0O   
sFilePath = value; I'PeN0T f  
} F_Z- 8>P  
;} und*q  
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public String getSFileName() fYp'&Btb]x  
{ D|@/yDQ  
return sFileName; m6n?bEl6I  
} =jlt5 z  
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public void setSFileName(String value) FQT~pfY  
{ dA@'b5N{"  
sFileName = value; _Xnqb+  
} Is]aj-#r  
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s
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public int getNSplitter() ld3-C55  
{ ;w'D4p= P  
return nSplitter; `jzTm
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} /b]oa!  
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public void setNSplitter(int nCount) ?z}=B  
{ hZh9uI7.  
nSplitter = nCount; ^
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} #Xhdn\7  
} P/xKnm~  
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/* uIcn{RZ_z  
**Utility.java A'G66ei  
*/ " Om[~-31  
package NetFox; hJwC~HG5  
D
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public class Utility { Atflf2K  
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public Utility() (Q%'N3gk  
{ ~\=1'D^6CK  
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L!
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} _7IKzUn9g[  
)N=NR2xB
Z  
//线程睡眠 D<8HZ%o  
public static void sleep(int nSecond) Ul2R'"FB  
{ d*A*y^OD  
try{ la( <8  
Thread.sleep(nSecond); T32+3wb"I  
} gN24M3{C  
catch(Exception e) '3TW [!m  
{ `9)t[7  
e.printStackTrace (); Z-E`>  
} *GxTX3i}vc  
} jov:]Bic  
}| J79s2M  
//日志 {Z3dF)>  
public static void log(String sMsg) m>4ahue$  
{ q6_u@:3u  
System.err.println(sMsg); JL\w_v  
} 5m?8yT}  
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*.\  
public static void log(int sMsg) ?sh
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{ |;.o8}  
System.err.println(sMsg); \"CZI<=TB  
} ta`N8vnf  
} $-#Yl&?z9  
58%#DX34M  
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/* e*@{%S  
**TestMethod.java A-,up{g  
*/ ##@$|6  
package NetFox; ?CC"Yij  
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public class TestMethod { K?s+3  
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public TestMethod() UNPezHaz  
{ ///xx/weblogic60b2_win.exe 2zVJ
vn7  
try{ w"OP8KA:^T  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); L3G \  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); BT)X8>ct  
SiteFileFetch fileFetch = new SiteFileFetch(bean); D[_|*9BC  
fileFetch.start(); SVv;q?jZ  
} TJ:]SB  
catch(Exception e){e.printStackTrace ();} h~(G$':^  
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} 0PU8#2pR  
([-|}  
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public static void main(String[] args) UJfEC0  
{ *uo'VJI7_,  
new TestMethod(); = M]iIWQ@`  
} {"&SJ
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} /1x,h"T\<  
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