http断点续传简单实现（java)

/* UFu0{rY_  
**SiteFileFetch.java 7U?#Xi5  
*/ *j,bI Y&se  
package NetFox; 
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import java.io.*; ZI1*Cb  
import java.net.*; <mj/P|P@  
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public class SiteFileFetch extends Thread { OU}eTc(FeC  
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SiteInfoBean siteInfoBean = null; //文件信息Bean mBb
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long[] nStartPos; //开始位置 H1L)9oa  
long[] nEndPos; //结束位置 B3D}'<  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 t&F:C  
long nFileLength; //文件长度 mEu2@3^E }  
boolean bFirst = true; //是否第一次取文件  o0>|  
boolean bStop = false; //停止标志 (6NDY5h~=n  
File tmpFile; //文件下载的临时信息 </@5>hx/  
DataOutputStream output; //输出到文件的输出流 ~d1=_p:~T  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） =:xX~,qmv  
public SiteFileFetch(SiteInfoBean bean) throws IOException LI25VDZ|iP  
{ ,4`Vl<6  
siteInfoBean = bean; 4nP4F+  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); b9"t%R9/Q  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); WT")tjVKA  
if(tmpFile.exists ()) a5s
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{ lJ]QAO  
bFirst = false; F$jy~W_  
read_nPos(); 5uahfJk  
} I)vR  
else K3`!0(  
{ SZLugyZ2Y  
nStartPos = new long[bean.getNSplitter()]; Y\WVkd(+G  
nEndPos = new long[bean.getNSplitter()]; zPybPE8  
} `OgT"FdL!  
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} tU2#Z=a  
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public void run() J$5G8<d>  
{ }CMGK
{  
//获得文件长度 ~@PD\  
//分割文件 =M4:nt  
//实例FileSplitterFetch E`(=n(Qu  
//启动FileSplitterFetch线程 8Dtpb7\o  
//等待子线程返回 (n:A`]  
try{ &4}=@'G@  
if(bFirst) WQ8 "Jj?k6  
{ Vp~ cN  
nFileLength = getFileSize(); ~|Ln9f-g  
if(nFileLength == -1) cF=WhP*f  
{ (3D&GY!/  
System.err.println("File Length is not known!"); <-b9 )>  
} ma@V>*u  
else if(nFileLength == -2) %,z;W-#gnY  
{ mVYfyLZ,(  
System.err.println("File is not access!"); Y/I)ECm  
} 1 hFh F^  
else 4ytdcb   
{ na8`V`77  
for(int i=0;i<nStartPos.length;i++) EmrkaV-?k  
{ hgW1g#
  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); GH-Fqz  
} "+7E9m6I  
for(int i=0;i<nEndPos.length-1;i++) N\Lu+ x5  
{ Ug546Bz  
nEndPos = nStartPos[i+1];
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} /FC HF#yK  
nEndPos[nEndPos.length-1] = nFileLength; jVN06,3z  
} 3<M yb  
} ?<W|Ya  
>K4Nn(~ys  
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//启动子线程 oOvQAW8`  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; %Gyn.9\  
for(int i=0;i<nStartPos.length;i++) $H)!h^7^9  
{ :2==7u7v?  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), .uS`RS8JM  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 0(f+a_2^Q  
nStartPos,nEndPos,i); =fnBE`Uc  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); n~\; +U  
fileSplitterFetch.start(); uHZ4 @w:  
} S#8)N`  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), wf]?:'}  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 1|xe'w{  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ]*mUc`  
nEndPos = " + nFileLength); @M-w8!.~  
// fileSplitterFetch[nPos.length-1].start(); R?:Q=7K  
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xl,% Z~[  
//等待子线程结束 lGR0-Gh2  
//int count = 0; 612,J  
//是否结束while循环 K`9~#Zx$  
boolean breakWhile = false; Q"{Dijc%  
cf,6";8  
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while(!bStop) #'>)?]tn  
{ ?uL-qsU  
write_nPos(); xcmg3:s  
Utility.sleep(500); Wj|W B*B  
breakWhile = true; ZpOME@9,  
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for(int i=0;i<nStartPos.length;i++) RDHK'PGA  
{ %Y;^$%X%_  
if(!fileSplitterFetch.bDownOver) [@VzpVhXz  
{ M_%
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breakWhile = false; _wb]tE ~g  
break; +8?18@obp  
} j[dZ*Jr_  
} FqbGT(QB0  
if(breakWhile) 5&EBUl}  
break; 6AY(/N8V  
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5;/q[oXI  
//count++; 1I69O6"  
//if(count>4) ETU-6qFtO  
// siteStop(); J>T98y/))  
} '
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System.err.println("文件下载结束！"); 9<3}zwJ  
} IZ>l  
catch(Exception e){e.printStackTrace ();} r7_%t_O|IL  
} :'<;]~f  
"DvZCf[}  
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//获得文件长度 <h#W
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public long getFileSize() gS[B;
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{ = )3\B  
int nFileLength = -1; Gq[5H(0/c  
try{ ,Il) tH  
URL url = new URL(siteInfoBean.getSSiteURL()); EMr|#}]#s  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); d\3 %5Y  
httpConnection.setRequestProperty("User-Agent","NetFox"); (:E@kpK  
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int responseCode=httpConnection.getResponseCode(); kzCJs  
if(responseCode>=400) \/ri|fm6l#  
{ ~V?z!3r-)  
processErrorCode(responseCode); @.k^ 8hc  
return -2; //-2 represent access is error > fV"bj.  
} Q -$) H;,  
rt*>)GI]b  
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String sHeader; "S'Yn-  
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for(int i=1;;i++) |/xA5_-N  
{ w]h8KNt  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); havmhS)O  
//Utility.log(in.readLine()); l-c:'n  
sHeader=httpConnection.getHeaderFieldKey(i); abS~'r14  
if(sHeader!=null) y?r`[{L(lA  
{ ~$^>Vo  
if(sHeader.equals("Content-Length")) T?A3f]U  
{ OUwnVAZZ6  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); e#}Fm;|d  
break; ^uw]/H3?L  
} HWFTI /]  
} J_yXL7d  
else pd,d"+  
break; Hq>hnCT  
} UB>BVBCt  
} s}UJv\*  
catch(IOException e){e.printStackTrace ();} +CSv@ />3  
catch(Exception e){e.printStackTrace ();} JP( tf+  
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Utility.log(nFileLength); tG9C(D`G  
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return nFileLength; 6q`)%"
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} Cq<Lj  
.
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#k &#d9}  
//保存下载信息（文件指针位置） G9jf]Ye
;  
private void write_nPos() !or_CJ8%  
{ {=&({ cS  
try{ sL\ {.ad5  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 2$t%2>1>@  
output.writeInt(nStartPos.length); @\oZ2sB  
for(int i=0;i<nStartPos.length;i++) mv,a>Cvs[  
{ [%6
)  
// output.writeLong(nPos); ?5};ONjN  
output.writeLong(fileSplitterFetch.nStartPos); Tu}EAr  
output.writeLong(fileSplitterFetch.nEndPos); M5:*aCN6P  
} ,|zzq@fk  
output.close(); <RC%<  
} CsT&}-C  
catch(IOException e){e.printStackTrace ();} w<]-~`K  
catch(Exception e){e.printStackTrace ();} <ycR/X  
} ;iJxJX\+  
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//读取保存的下载信息（文件指针位置） q;sZwp<  
private void read_nPos() C+`V?rp=s  
{ >XiT[Ru
 
try{ &AeNrtGu  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); /yx)_x{  
int nCount = input.readInt(); qJonzFp7  
nStartPos = new long[nCount]; /<+`4n  
nEndPos = new long[nCount]; 4eSFpy1  
for(int i=0;i<nStartPos.length;i++) cud9oJ-=;  
{ =^{MyR7  
nStartPos = input.readLong(); 1#+|RL4o  
nEndPos = input.readLong(); F)imeu  
} @;hdZLG]`&  
input.close(); L5|g\Y`  
} cmCD}Skk  
catch(IOException e){e.printStackTrace ();} T9kc(i'  
catch(Exception e){e.printStackTrace ();} s0x/2z  
} 6 A#xFPYY{  
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private void processErrorCode(int nErrorCode) w"QZ7EyJ  
{ 5~2_wWjX  
System.err.println("Error Code : " + nErrorCode); S^EAE]  
} BE~-0g$W  
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//停止文件下载 C#)T$wl[E  
public void siteStop() JxLfDr,dy  
{ <X& fs*x&  
bStop = true; nf&5oE^  
for(int i=0;i<nStartPos.length;i++) /PR4ILed  
fileSplitterFetch.splitterStop(); Y"s8j=1m  
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} #&L7FBJ"*v  
} Z6Kp-z(l3  
//负责部分文件的抓取 \M0's&1(  
**FileSplitterFetch.java A9"!=/~  
*/ 7kT X  
package NetFox; `GCK%evLG  
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import java.io.*; UVgSO|Tg  
import java.net.*; 0,.|-OZ  
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public class FileSplitterFetch extends Thread { +StsSZ  
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String sURL; //File URL H/;AlN|!  
long nStartPos; //File Snippet Start Position EdSUBoWF}  
long nEndPos; //File Snippet End Position fZ;}_wR-H  
int nThreadID; //Thread's ID |Sua4~yL(  
boolean bDownOver = false; //Downing is over MLmaA3  
boolean bStop = false; //Stop identical elpTak@  
FileAccessI fileAccessI = null; //File Access interface 1~LfR  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException C=cn.CX  
{ ~82 {Y _{/  
this.sURL = sURL; $% gz,{  
this.nStartPos = nStart; 7^LCP*  
this.nEndPos = nEnd; :$PrlE  
nThreadID = id; +o"CMI  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 "5sA&^_#_  
} ?cKTeGrS  
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public void run() Cx.##n0  
{ VEn3b  
while(nStartPos < nEndPos && !bStop) T0)b
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{ k%kEW%I yG  
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try{ p|dn&<kd  
URL url = new URL(sURL); H=g%>W%3  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); #Er"i  
httpConnection.setRequestProperty("User-Agent","NetFox"); Q6e7Z-8  
String sProperty = "bytes="+nStartPos+"-"; eO*s,*  
httpConnection.setRequestProperty("RANGE",sProperty); 6%>'n?  
Utility.log(sProperty); F[!%,-*  
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InputStream input = httpConnection.getInputStream(); Iwh0PfWJ  
//logResponseHead(httpConnection); j|N<6GSke  
) jvI Nb  
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#  
byte[] b = new byte[1024]; [?O4l`  
int nRead; 5;XYF0  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 6-)WXJ@V  
{ (c^ {T)  
nStartPos += fileAccessI.write(b,0,nRead); 6akI5\b  
//if(nThreadID == 1) b09xf"D  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ',t*:GBZCf  
} d,Oagx  
K9p<PL
y+  
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Utility.log("Thread " + nThreadID + " is over!"); }HmkTk  
bDownOver = true; CmBgay  
//nPos = fileAccessI.write (b,0,nRead); O"\_%=X9  
} M"/Jn[  
catch(Exception e){e.printStackTrace ();} : xg
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} ju"?b2f  
} rBi<Yy$z  
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//打印回应的头信息 5$HG#2"Kb#  
public void logResponseHead(HttpURLConnection con) d^!k{Qx'  
{ f5b|,JJ  
for(int i=1;;i++) U1E@pDH  
{ ?*+U[*M  
String header=con.getHeaderFieldKey(i); SOM? 0.  
if(header!=null) :l!sKT?:d!  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); z5(5\j]  
Utility.log(header+" : "+con.getHeaderField(header)); yI#qkl-  
else G
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break;
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} . _|=Btoo  
} V;"2=)X  
Cb? !+U  
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public void splitterStop() 3Wbd=^hRvq  
{ A:GqR;;"x>  
bStop = true; A
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} :/szA?:W  
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} O TlqJ  
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/* Tgtym"=xd  
**FileAccess.java Y,Z$U| U  
*//文件访问(定位，写) 5YNAb/!!F  
package NetFox; #-G@p  
import java.io.*; :.XlAQR~b  
2#lpIj  
y'odn;  
public class FileAccessI implements Serializable{ gL&w:_  
C
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 fg#e*7Odn  
RandomAccessFile oSavedFile;  ArAe=m!u  
long nPos; JkT!X  
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public FileAccessI() throws IOException f&^}yqmuE  
{ TsoxS/MI"  
this("",0); .$x}~Sw  
} BV>9U5  
*k,3@_5  
a BMV6'  
public FileAccessI(String sName,long nPos) throws IOException ),B/NZ/-  
{ ri59LYy=  
oSavedFile = new RandomAccessFile(sName,"rw"); u;rmqo1  
this.nPos = nPos; (n?f016*%d  
oSavedFile.seek(nPos); 8gEp5  
} fcF|m5  
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public synchronized int write(byte[] b,int nStart,int nLen) 8YRT0/V  
{ >\pF5a`  
int n = -1; W?4:sLC#3  
try{ 5ILKYUg,  
oSavedFile.write(b,nStart,nLen); 3-:^mRPJ  
n = nLen; Ar/P%$Zfq  
}
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catch(IOException e) vW*Mf}=  
{ oi7k#^  
e.printStackTrace (); #BBDI  
} k}<H  
.@nfqv7{  
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return n; j1{`}\e  
} 0.R3(O  
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} iExKi1knx  
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y,&[OrCm^\  
/* -wC}JVVcK  
**SiteInfoBean.java !L9|iC:8  
*/ By7lSbj  
package NetFox; ~s'}_5;VY  
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l{8O'4;  
public class SiteInfoBean { [
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) aMiT  
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private String sSiteURL; //Site's URL $0$sDN6)x  
private String sFilePath; //Saved File's Path \^y~w~g?  
private String sFileName; //Saved File's Name 7#UJ444b~  
private int nSplitter; //Count of Splited Downloading File sxF2ku4A  
6 A]a@,PC  
k3B_M9>!  
public SiteInfoBean() *zweZG8:  
{//nSplitter的缺省值为5 /K!f3o+  
//default value of nSplitter is 5 5 8;OTDR!  
this("","","",5); F)eP55C6  
} Oz(=%oS  
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z)*{bz]  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ~0-)S@  
{ o(54 A['  
sSiteURL= sURL; .HY,'oC.  
sFilePath = sPath; X04LAYY_u  
sFileName = sName; GcO:!b*YMp  
this.nSplitter = nSpiltter; e&ZTRgYdi  
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K`X'Hg#_P2  
} 94 6r#`q  
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public String getSSiteURL() Snmv  
{ ;IPk+,hpmi  
return sSiteURL; Xs$a^zZ  
} 751Qi  
wS7Vo{#@\  
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public void setSSiteURL(String value) 8VG~n?y  
{ DTi^* Wj  
sSiteURL = value;
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} O<>+l*bk  
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public String getSFilePath() dn=srbJ   
{ 4C:dkaDq]  
return sFilePath; 3ErV" R4"$  
} d=vD Pf  
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public void setSFilePath(String value) D"fjk1  
{ gLo&~|=L-  
sFilePath = value;  +
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} l_2l/ff9  
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p ~+sk1[.  
public String getSFileName() kwS[,Qy\  
{ Bv*VNfUm  
return sFileName; }VH2G94Ll  
} wc}x [cS  
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public void setSFileName(String value) 0}kvuuR  
{ vj#m#1\f  
sFileName = value; 3XbFg%8YG  
} !+UXu]kA  
!([v=O#
 
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public int getNSplitter()
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{ rg%m
 
return nSplitter; rX`fjS*C  
} 'P&r^V\~(/  
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public void setNSplitter(int nCount) 98{n6$\  
{ 
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nSplitter = nCount; {+9t!'   
} hNp.%XnnZ  
} ,~K4+ t_  
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/* ,zBc-Cm  
**Utility.java ^M1O)   
*/ |ew:}e: k<  
package NetFox; )B5U0iIi  
P[Vf$ q<  
}L5;=A']S  
public class Utility { =G rg  
vZSwX@0  
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public Utility() B8V85R  
{ 57U;\L;ZmZ  
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} Fi+,omB&  
V}G;oz&>)  
//线程睡眠 00A2[gO9  
public static void sleep(int nSecond) C2J@]&  
{ Cz4l  
try{ Vao3&#D8  
Thread.sleep(nSecond); JG'&anbm  
} 7I6&*I  
catch(Exception e) nyd'79~>G  
{ YW-Ge  
e.printStackTrace (); 5kj=Y]9\I  
} N8]d0  
} NVo=5  
}j#c#''i  
//日志 `q1K%id  
public static void log(String sMsg) _d3/="=  
{ &e
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System.err.println(sMsg); cU=EXyP%  
} zeHs5P8}r  
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S 5nri(m  
public static void log(int sMsg) -M?s<R[&  
{ }Xy<F?Mh  
System.err.println(sMsg); j&=!F3[  
} ?$X1X`@  
} & Pzr)W(  
,O"zz7  
Y!nE65  
/* 0SWec7G  
**TestMethod.java z4c{W~}`  
*/ kA<58,!  
package NetFox; 'd=B{7k@  
C&KH.h/N  
mE_?E&T`|  
public class TestMethod { Y[ toN9,  
i!EN/Bd  
pD%Pg5p`  
public TestMethod() c27A)`   
{ ///xx/weblogic60b2_win.exe *4
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try{ 8;]U:tv  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); E h>qUa  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); P_ x9:3  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 8!{F6DG  
fileFetch.start(); 8DP] C9  
} x*uQBNf=  
catch(Exception e){e.printStackTrace ();} W-+~r  
#Y;_W;#  
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} `-L{J0xq  
oO8V0VE\  
2-*zevPiG=  
public static void main(String[] args) Y^-faL7*\  
{ UfnjhHu  
new TestMethod(); 9'|NF<  
} IirXF?&t  
} 9,`eYAu  
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