http断点续传简单实现（java)

/* /\{emE\]  
**SiteFileFetch.java u69UUkG  
*/ OdbXna  
package NetFox; ff;~k?L  
import java.io.*; P;`Awp?  
import java.net.*; uBK0+FLL@  
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public class SiteFileFetch extends Thread { 5sANF9o!  
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SiteInfoBean siteInfoBean = null; //文件信息Bean d#OAM;0}5  
long[] nStartPos; //开始位置 d_,Ql708f  
long[] nEndPos; //结束位置 +%f6{&q$  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 b"aF-,M>  
long nFileLength; //文件长度 hFo29oN  
boolean bFirst = true; //是否第一次取文件 A`#?Bj  
boolean bStop = false; //停止标志 eBH:_Ls_-^  
File tmpFile; //文件下载的临时信息 dF[|9%)  
DataOutputStream output; //输出到文件的输出流 hF{gN3v5  
^RJ@9`P&t  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 9Fy'L#%  
public SiteFileFetch(SiteInfoBean bean) throws IOException le' Kp V  
{ OwT_W)$  
siteInfoBean = bean; A=0{}B#  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Y7zs)W8xTT  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); l$Vy\CfK3n  
if(tmpFile.exists ()) xL*J9&~iG  
{ >$tU @mq  
bFirst = false; HC=ZcK'W  
read_nPos(); wH$qj'G4CN  
} ohbU~R3{U  
else _Vl~'+e  
{ -u(,*9]cJ*  
nStartPos = new long[bean.getNSplitter()]; Lk!m1J5  
nEndPos = new long[bean.getNSplitter()]; eR,/}g\  
} c4u/tt.)  
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} Do77V5  
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public void run() H~TuQ  
{ L2p?]:-  
//获得文件长度 064k;|>D  
//分割文件 oNIYO*[  
//实例FileSplitterFetch < =~=IZ)  
//启动FileSplitterFetch线程 I-}ms  
//等待子线程返回 zrqI^i"c  
try{ S]ayH$w\Q  
if(bFirst) N,Z*d  
{ 4 ob?M:S  
nFileLength = getFileSize(); "P0!cY8r  
if(nFileLength == -1) }S8aR:'  
{  B$6KI  
System.err.println("File Length is not known!"); E}KGZSj  
} $#-rOi /  
else if(nFileLength == -2) {:3
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{ HAL\j5i  
System.err.println("File is not access!"); %g:'6%26  
} IIih9I`IR  
else ?Wz2J3A.2t  
{ 2GORGS%  
for(int i=0;i<nStartPos.length;i++) (c)=Do=  
{ 8HFCmY#  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ?_FL 'G  
} V'e%%&g~N  
for(int i=0;i<nEndPos.length-1;i++) Q 8Hl7__^  
{ PDPK|FU  
nEndPos = nStartPos[i+1]; P))BS  
} p5$}h,7  
nEndPos[nEndPos.length-1] = nFileLength; QRvyaV  
} 6`7tTn?n  
} #2s}s<Sc;  
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//启动子线程 rH!sImz,  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; _]33Ht9  
for(int i=0;i<nStartPos.length;i++) ~Ni  
{ z]r'8Jc  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), v@|<.  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ~h_ _Y>  
nStartPos,nEndPos,i); 
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); \wD/TLS}  
fileSplitterFetch.start(); CV\^gTPmx  
} EYn?YiVFU  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), w$/lq~zU  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); h$kz3r;b,"  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ,|d9lK`"P  
nEndPos = " + nFileLength); _Iminet  
// fileSplitterFetch[nPos.length-1].start(); iMJt8sd  
:P}3cl_  
:Rb\Ca  
//等待子线程结束 j
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//int count = 0; {N
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//是否结束while循环 `@ YV  
boolean breakWhile = false; {Y@shf;  
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while(!bStop) 'bJGQ[c  
{ Bkd$'
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write_nPos(); e)wi}\:q_  
Utility.sleep(500); _$
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breakWhile = true; ed`
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for(int i=0;i<nStartPos.length;i++) 0: a2ER|J  
{ $*942. =Q  
if(!fileSplitterFetch.bDownOver) pdRM%ug   
{ ?/OF=C#  
breakWhile = false; CdF;0A9.3  
break; o *J*}y  
} Ny2 Z <TW  
} La )M  
if(breakWhile) jcJ 4?  
break; 8j;Un]  
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//count++; 6&os`!  
//if(count>4) S~);   
// siteStop(); >^~^
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} ;:D-}t;  
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System.err.println("文件下载结束！"); u-t=M]  
} ]0."{^ksL  
catch(Exception e){e.printStackTrace ();} a2B71RT~  
} ;&&<zWq3h  
]UkH}Pt'3  
-`I|=lBz{H  
//获得文件长度 QCW4gIp  
public long getFileSize() %PYO9:n  
{ bFX{|&tHU  
int nFileLength = -1; Mpojabsh  
try{ 6^gp /{  
URL url = new URL(siteInfoBean.getSSiteURL()); S/XU4i:aV  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); kM506U<g  
httpConnection.setRequestProperty("User-Agent","NetFox"); Cjf[]aNJe`  
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int responseCode=httpConnection.getResponseCode(); f256;3n  
if(responseCode>=400) J _
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{ ww^\_KGu7  
processErrorCode(responseCode); ~o!-[  
return -2; //-2 represent access is error wtek5C^  
} VO:4wC"7  
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String sHeader; uI-T]N:W8x  
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for(int i=1;;i++) =IC.FT}  
{ mITB\,,G  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); op}!1y$9P  
//Utility.log(in.readLine()); S?0o[7(x*  
sHeader=httpConnection.getHeaderFieldKey(i); 'GJB9i+a^  
if(sHeader!=null) [
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{ h9Far8}  
if(sHeader.equals("Content-Length")) "r&,#$6W6  
{ P$obID  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); `DY yK?R  
break; N]+6<  
} 5?-HQoT)G  
} wD9K\%jIr!  
else ^Gk`n  
break; zTg\\z;  
} XZIapT  
} '|IcL1c=I  
catch(IOException e){e.printStackTrace ();} l ;:IL\*1I  
catch(Exception e){e.printStackTrace ();} }Z"iW/?"  
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Utility.log(nFileLength); l53i {o  
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return nFileLength; 4`,(*igEv  
} R
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//保存下载信息（文件指针位置） Bg~]
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private void write_nPos() z
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{ dVb6u  
try{ \(Sly&gL  
output = new DataOutputStream(new FileOutputStream(tmpFile)); x?wvS]EBg  
output.writeInt(nStartPos.length); H3rA ?F#+*  
for(int i=0;i<nStartPos.length;i++) =p@`bx  
{ !2|Lb'O  
// output.writeLong(nPos); cdMSC7l!  
output.writeLong(fileSplitterFetch.nStartPos); hObL=^F  
output.writeLong(fileSplitterFetch.nEndPos); &42]#B"*  
} !vwio!  
output.close(); ]UvB+M]Lv)  
} !J7`frv"(  
catch(IOException e){e.printStackTrace ();} 8o5[tl ?w  
catch(Exception e){e.printStackTrace ();} [{7#IZL  
} _
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stRM*.  
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//读取保存的下载信息（文件指针位置） )7 p" -  
private void read_nPos() ]M5~p^ RB  
{ ^@^8iZ  
try{ T)mQ+&|  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ?6:qAFw  
int nCount = input.readInt(); oV%:XuywT  
nStartPos = new long[nCount]; eI1zRoIl-  
nEndPos = new long[nCount]; H a!,9{T  
for(int i=0;i<nStartPos.length;i++) 0/Q_% :  
{ P)Adb~r  
nStartPos = input.readLong(); kd'b_D[$H  
nEndPos = input.readLong(); D]@(LbMG4  
} <&E}db  
input.close(); tRoSq;VrS  
} Z@Rm^g]o  
catch(IOException e){e.printStackTrace ();} Q#p)?:o/  
catch(Exception e){e.printStackTrace ();} {xTq5`&gT  
} W3.[d->X  
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private void processErrorCode(int nErrorCode) F1yn@a "=J  
{ );0  
System.err.println("Error Code : " + nErrorCode); p'h'Cz  
} _
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//停止文件下载 px;~20$e  
public void siteStop() 1-gM)x{Jr  
{ tyR?A>F4  
bStop = true; Ub3$`  
for(int i=0;i<nStartPos.length;i++) lM\dK)p21O  
fileSplitterFetch.splitterStop(); i<ES/U\  
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} 2y!n c%  
} zVE" 6  
//负责部分文件的抓取 ~-'2jb*8  
**FileSplitterFetch.java )U\i7[k>  
*/ !BoGSI  
package NetFox; \g34YY^L3  
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import java.io.*; M XG>|  
import java.net.*; [E9iuym  
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public class FileSplitterFetch extends Thread { ;<FAcR  
%j&vV>2  
+-!3ruwSn  
String sURL; //File URL d*6f,z2=  
long nStartPos; //File Snippet Start Position :BxO6@>Xc  
long nEndPos; //File Snippet End Position H1-DK+Q:  
int nThreadID; //Thread's ID BwH
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boolean bDownOver = false; //Downing is over .B`$hxl*0c  
boolean bStop = false; //Stop identical S|=)^$:  
FileAccessI fileAccessI = null; //File Access interface ?nc:bC  
=CQfs6np:N  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException MXSD8]
je  
{ g(&cq  
this.sURL = sURL; H>+/k-n-  
this.nStartPos = nStart; t=7Gfv
 
this.nEndPos = nEnd; UuIjtqW  
nThreadID = id;  9tpyrGv  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ika*w  
} E]#;K-j  
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public void run() L\4rvZa  
{ 8
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while(nStartPos < nEndPos && !bStop) >M5}L<  
{ f,O10`4s  
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try{ 1:eWZ]B5"  
URL url = new URL(sURL); =o(}=T>:"  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); R,T0!f  
httpConnection.setRequestProperty("User-Agent","NetFox"); n~l
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}  
String sProperty = "bytes="+nStartPos+"-"; s4Ja y!A  
httpConnection.setRequestProperty("RANGE",sProperty); +Ug &  
Utility.log(sProperty); x;
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InputStream input = httpConnection.getInputStream(); HK[%'OQ  
//logResponseHead(httpConnection); _&=`vv'  
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byte[] b = new byte[1024]; Jz''UJY/O  
int nRead; 7T[L5-g  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) OXLB{|hH80  
{ 2]fTDKh  
nStartPos += fileAccessI.write(b,0,nRead); tM5(&cQ!d  
//if(nThreadID == 1) z 4}"oQk:r  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *$7^.eHfdd  
} %ZRv+}z  
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:+YHj)mN  
Utility.log("Thread " + nThreadID + " is over!"); +/&rO,Ql  
bDownOver = true; Yh]a4l0  
//nPos = fileAccessI.write (b,0,nRead); bAt!S  
} *c#DB{N  
catch(Exception e){e.printStackTrace ();} |e8A)xM]wC  
} (U5XB [r_P  
} ZvuY]=^3  
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7UBW3{d/u5  
//打印回应的头信息 -F`gRAr-  
public void logResponseHead(HttpURLConnection con) .x$V~t  
{ E`N`  
for(int i=1;;i++) <w&'E6mU  
{ O4-#)#-)S~  
String header=con.getHeaderFieldKey(i); Wda?$3!^q  
if(header!=null) N_D=j6B  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 23LG)or.JC  
Utility.log(header+" : "+con.getHeaderField(header)); C=c&.-Nb9  
else e|A=sCN-  
break; Rq15AR  
} i.9}bw 9u@  
} <!dZ=9^^1  
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public void splitterStop() '!X`X=  
{ :TrP3wV_  
bStop = true; -X EK[  
} s,J\nbj0h  
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} !h&h;m/c  
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/* '(ETXQ@  
**FileAccess.java Q-_;.xy#4  
*//文件访问(定位，写) a&)$s;
  
package NetFox; s/?(G L+Ae  
import java.io.*; 3rh t5n2-  
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w#(E+s~}  
public class FileAccessI implements Serializable{ <y-2ovw*  
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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 IL8&MA%  
RandomAccessFile oSavedFile; A}!D&s&UH  
long nPos; n-9X<t|*?a  
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public FileAccessI() throws IOException d#,   
{ .@(MNq{"6  
this("",0); D//Ts`}+n  
} &)Wm rF  
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public FileAccessI(String sName,long nPos) throws IOException ]=^NTm,  
{ am WIA`n=  
oSavedFile = new RandomAccessFile(sName,"rw"); #5kg3OO  
this.nPos = nPos; h1_KZ[X  
oSavedFile.seek(nPos); `Oi6o[a  
} ZONe
}tv:  
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public synchronized int write(byte[] b,int nStart,int nLen) 0Ioa;XgOn  
{ W$Z""
 
int n = -1; < uzDuBN  
try{ Yv;18j*<  
oSavedFile.write(b,nStart,nLen); 0wl31k{  
n = nLen; 0Z[8d0  
} nIP*yb}5  
catch(IOException e) oY%NDTVN  
{ qxwD4L`S  
e.printStackTrace (); XAr YmO  
} D(S^g+rd  
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return n; bxg9T(Bj
 
} #$>m`r  
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} tm}0kWx  
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oW/ #/;|`  
/* Xn3Ph!\Z5e  
**SiteInfoBean.java .),m7
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*/ @(A[H^E  
package NetFox; dAcy;-[[P  
#}!Ge  
;HeUD5Nt6F  
public class SiteInfoBean { VS\~t  
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W`-AN}C#  
private String sSiteURL; //Site's URL %<8lLRl  
private String sFilePath; //Saved File's Path 4`7:gfrO,  
private String sFileName; //Saved File's Name !7-dqw%l  
private int nSplitter; //Count of Splited Downloading File x-/`c  
/u8m|S<  
rBZ0(XSZQ  
public SiteInfoBean() V1j5jjck  
{//nSplitter的缺省值为5 /r Hd9^Y  
//default value of nSplitter is 5 N?h=Zl|  
this("","","",5); ]I#yS=;  
} +idj,J|  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) O#E]a<N`  
{ Y\len  
sSiteURL= sURL; C0X_t  
sFilePath = sPath;
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sFileName = sName; Ii/#cdgF  
this.nSplitter = nSpiltter; :U>o;  
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} uFIr.U$V  
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public String getSSiteURL() V&E)4KBOs  
{ }^;Tt-*k  
return sSiteURL; +.T&U7x
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} wG4=[d  
wvum7K{tI  
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public void setSSiteURL(String value) %SL'X`j  
{ N246RV1W  
sSiteURL = value; WUSkN;idVG  
} 4 e1=b,  
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p`)(  
public String getSFilePath() `w1|(Sk$h  
{ f:gXXigY,  
return sFilePath; qr[H0f]  
} G/Nb@pAy[  
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public void setSFilePath(String value) =#||&1U$  
{ \-Mzs 0R  
sFilePath = value; <taN3  
} s_A<bW566F  
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public String getSFileName() ]42bd  
{ ?+)O4?#  
return sFileName; *Y'@|xf*  
} fGDR<t3yiQ  
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public void setSFileName(String value) _,Wb`P  
{ n$n)!XL/  
sFileName = value; L|Zja*  
} 4hb<EH'_&  
X(nbfh?n  
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public int getNSplitter() F3$@6J8<[z  
{ $gU6=vN1#  
return nSplitter;  ~{7/v  
} iO)FZ%?"  
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public void setNSplitter(int nCount) / E~)xgPM<  
{ =c 3;@CO  
nSplitter = nCount; Ww&~ZZZ {  
} 8.4
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} \^O#)&5 V  
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/* +.gM"JV  
**Utility.java 42X N*br  
*/ -I-u.
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package NetFox; #p@8m_g  
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=$5[uI2  
public class Utility { 0_bt*.wI+  
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public Utility() >p!d(J?  
{ EU,4qO  
^ j@Q2>&?  
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} ?{qw /&  
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//线程睡眠 `<t{NJ&f  
public static void sleep(int nSecond) L&ws[8-  
{ 8{Y ?;~G  
try{ &RXd1>|c2  
Thread.sleep(nSecond); y{ 90A  
} k`js~/Xv  
catch(Exception e) 0[D5]mcv  
{ )T#;1qNB  
e.printStackTrace (); ,@!8jar@w}  
} MvY0?!v  
} <E@7CG.=  
6u7(}K  
//日志 /+RNPQO O  
public static void log(String sMsg) u7j-uVG  
{ !U>"H8}dv  
System.err.println(sMsg); 1s\10 hK1c  
} *ILS/`mdav  
q30
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ao
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public static void log(int sMsg) $?Aez/  
{ d5A!kU _.  
System.err.println(sMsg); QY+#Vp<`  
} 0&/1{Dk*n  
} NJUYeim;  
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/* E
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**TestMethod.java ZX-9BJ`Q  
*/ Q77
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package NetFox; ![Ip)X OG  
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2+=|!+f  
public class TestMethod { ";s5It  
JF{,;&sj  
3jS=  
public TestMethod() |B`-chK  
{ ///xx/weblogic60b2_win.exe =_":Z!_  
try{ X8Sk  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Nr`nL_DQ  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); #0`"gR#+  
SiteFileFetch fileFetch = new SiteFileFetch(bean);
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fileFetch.start(); !-.-!hBN  
} @O45s\4-*  
catch(Exception e){e.printStackTrace ();} uTl:u  
kl
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0[v:^H  
} W77JXD93  
#eUfwd6.Y  
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public static void main(String[] args) Z;>~<#!4  
{ J`RNik*>  
new TestMethod(); IN%>46e`  
} }2NH>qvY  
} 'oT}jI
 
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