http断点续传简单实现（java)

/*
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**SiteFileFetch.java h.t2;O,b  
*/ PrQs_tNi  
package NetFox; ,6Ua+\|  
import java.io.*; ?S2!'L  
import java.net.*; M/x*d4b_  
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public class SiteFileFetch extends Thread { w8KVs\/  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Om,M8!E  
long[] nStartPos; //开始位置 w~|z0;hC  
long[] nEndPos; //结束位置 *.P3fVlZ  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Jc9BZ`~i  
long nFileLength; //文件长度 3:
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boolean bFirst = true; //是否第一次取文件 ?ISv|QpC  
boolean bStop = false; //停止标志 %CaF-m=Pq  
File tmpFile; //文件下载的临时信息 x6iT"\MO  
DataOutputStream output; //输出到文件的输出流 K/A1g.$  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） U#gv ~)\k  
public SiteFileFetch(SiteInfoBean bean) throws IOException D//uwom  
{ wM0P#+bA\  
siteInfoBean = bean; L9bIdiB7  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); p6*|)}T_%  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Kc#42C;t/  
if(tmpFile.exists ()) IzWS6!zKU  
{ \0bZ1"  
bFirst = false; mA" 82"   
read_nPos(); 
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} Xxmvg.Nl  
else Xhk_h2F[  
{ nNP{>\x;"  
nStartPos = new long[bean.getNSplitter()]; _usi~m  
nEndPos = new long[bean.getNSplitter()]; <&87aDYz  
} r$/.x6g//  
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} <pp<%~_Z  
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public void run() MU#$tXmnC  
{ RI0+9YJ  
//获得文件长度 -)o0P\cTEt  
//分割文件 bqI| wGCA"  
//实例FileSplitterFetch ?YA5g' l  
//启动FileSplitterFetch线程 PTf.(B"z  
//等待子线程返回 F qH@iZ  
try{ zrazFI0G  
if(bFirst) 'boAv%1_sa  
{ nv-_\M   
nFileLength = getFileSize(); +jrMvk"  
if(nFileLength == -1) c ;@k\6  
{ YA'_Ba(v)  
System.err.println("File Length is not known!"); jb {5   
} w@Gk#  
else if(nFileLength == -2) EVE<LF?
 
{ 63Dm{ 2i}F  
System.err.println("File is not access!"); r<XlIi  
} I]B[H6  
else 0ofl,mXW  
{ cd?arIV5  
for(int i=0;i<nStartPos.length;i++) Z`97=:W  
{ QU%'z/dip  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); :eR[lR^4*  
} Mz:t[rfs  
for(int i=0;i<nEndPos.length-1;i++) +E-f  
{ WC ZDS>  
nEndPos = nStartPos[i+1]; @ZFU< e$!  
} NX5NE2@^qH  
nEndPos[nEndPos.length-1] = nFileLength; uom~,k$|  
} i
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} ;x~[om21;  
U<Z\jT[  
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//启动子线程 |&xjuBC  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; y|0I3n]e  
for(int i=0;i<nStartPos.length;i++) D-!#TN`Y  
{ BH$+{rZ8t  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 3V2w1CERE  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), j"Vb8}  
nStartPos,nEndPos,i); $v*0\O  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); YTo^Q&  
fileSplitterFetch.start(); ;rJ  
} Zd]2>h  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), OcLFVD=  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); M_monj}Z  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", eOI#T'
5  
nEndPos = " + nFileLength); cojbuo  
// fileSplitterFetch[nPos.length-1].start(); my(yN|  
9b}AZ]$  
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//等待子线程结束 !&=%#i  
//int count = 0; D8I)3cXa'  
//是否结束while循环 <1EmQ)B  
boolean breakWhile = false; ~RS^Opoa  
{Q@pF  
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while(!bStop) 6opubI<  
{ <0hJo=6a8  
write_nPos(); uY5Gn.Y  
Utility.sleep(500); S.kFs{;1x  
breakWhile = true; dPfDPb  
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for(int i=0;i<nStartPos.length;i++) 9&t!U+  
{ ;"@FLq(n  
if(!fileSplitterFetch.bDownOver) H%\\-Z$#  
{ D@yuldx'/  
breakWhile = false; 8*V8B=q}K  
break; u
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} l8_TeO  
} ^"Nsb&  
if(breakWhile) 1q[vNP=g&  
break; koizk&)  
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P=jbr"5Q:  
//count++; U2(|/M+  
//if(count>4) dGb]`*E  
// siteStop(); c*"TmDY  
} s3LR6Z7;i  
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System.err.println("文件下载结束！"); 2\,vq R  
} 5E#koy7 $s  
catch(Exception e){e.printStackTrace ();} fW
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} u+RdC
;_  
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//获得文件长度 }Pj3O~z  
public long getFileSize() 1jhGshhp  
{ 1K;i/  
int nFileLength = -1; $*Q_3]AY]  
try{ 1wqsGad+;  
URL url = new URL(siteInfoBean.getSSiteURL()); |5}~n"R5  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); q&-A}]  
httpConnection.setRequestProperty("User-Agent","NetFox"); V %cU@  
]v^;]0vcr  
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int responseCode=httpConnection.getResponseCode(); *<**rY*  
if(responseCode>=400) Z`l97$\  
{ EPz$`#Sh"  
processErrorCode(responseCode); /?; 8F  
return -2; //-2 represent access is error _S(]/d(c
 
} 5[Ryc[  
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| ZI~#V  
String sHeader; BlVk?n  
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for(int i=1;;i++) V+()`>44  
{ _faI*OY8  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); w:z@!<  
//Utility.log(in.readLine()); tzxp0&:Z].  
sHeader=httpConnection.getHeaderFieldKey(i); m_TZY_;  
if(sHeader!=null) jaAv_=93f  
{ U/B1/96lJ  
if(sHeader.equals("Content-Length")) $rySz7NI  
{ ^;2dZgJ4^  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); <N%8"o  
break; \Mv8pU  
} ;n*N9-|.  
} Z:#-4CiP  
else H>-?/H  
break; {V!Jj6n  
} =#i#IF42?  
} j${:Y$V
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catch(IOException e){e.printStackTrace ();} UC^Bn1  
catch(Exception e){e.printStackTrace ();} nFl=D=50-  
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Utility.log(nFileLength); c 25wm\\  
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return nFileLength; >?,arER  
} v UAYYe  
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//保存下载信息（文件指针位置） *HmL8c  
private void write_nPos() C.{*|#&GAt  
{ icF -
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try{ P'D
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output = new DataOutputStream(new FileOutputStream(tmpFile)); Y"mD)\Bw?  
output.writeInt(nStartPos.length); ,>%AEN6N2  
for(int i=0;i<nStartPos.length;i++) 3:a}<^DuCS  
{  ]D7z&h  
// output.writeLong(nPos); B{W2D  
output.writeLong(fileSplitterFetch.nStartPos); oOuhbFu  
output.writeLong(fileSplitterFetch.nEndPos); 1;ulqO  
} i4.s_@2Y  
output.close(); S\Qh#yFT  
} #](k,% 2  
catch(IOException e){e.printStackTrace ();} 4];Qpln  
catch(Exception e){e.printStackTrace ();} x#e(&OjN7  
} Nh41o0  
#3$U&|`  
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//读取保存的下载信息（文件指针位置） V9"Kro  
private void read_nPos() 0.nS306  
{ q+32|k>)  
try{ ~Xnq(}?ok  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); dCcV$BX,K  
int nCount = input.readInt(); p;) ;Vm+8  
nStartPos = new long[nCount]; -o F#a 8  
nEndPos = new long[nCount]; pF.Ws,nQ5  
for(int i=0;i<nStartPos.length;i++) n(a7%Hx2  
{ F5%-6@=  
nStartPos = input.readLong(); 3vOI=ar=L~  
nEndPos = input.readLong(); qTiUha9  
} C%v@u$N  
input.close(); -,96Qg4vI  
} 0At??Zpy  
catch(IOException e){e.printStackTrace ();} b]mRn{r?  
catch(Exception e){e.printStackTrace ();} 0i$jtCCL(  
} kT UQ8U  
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private void processErrorCode(int nErrorCode) K4xZT+Qb  
{ %yQ-~T@  
System.err.println("Error Code : " + nErrorCode); *ZGQ`#1.X6  
} mCtuyGY  
)xP]rOT  
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//停止文件下载 @P"q`*  
public void siteStop() )G ,LG0"-  
{ gi:;{  
bStop = true; Ih`
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for(int i=0;i<nStartPos.length;i++) bqf=;Nvog  
fileSplitterFetch.splitterStop(); X8bo?0  
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} +:It1`A~]  
}
+F 6KGK[  
//负责部分文件的抓取 6%ID*  
**FileSplitterFetch.java uGLVY%N  
*/ (7}v}3/  
package NetFox; Q-}oe Q
 
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import java.io.*; RGLwtN  
import java.net.*; NEZF q?  
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public class FileSplitterFetch extends Thread { C-_u; NEu  
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String sURL; //File URL &66G  
long nStartPos; //File Snippet Start Position uzZ|w+3O  
long nEndPos; //File Snippet End Position KfWVz*DC!  
int nThreadID; //Thread's ID |fTQ\q]W  
boolean bDownOver = false; //Downing is over OU9=O>  
boolean bStop = false; //Stop identical s&y  
FileAccessI fileAccessI = null; //File Access interface 4_t aCK  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException &.7\{q\(  
{ -mX _I{BJ  
this.sURL = sURL; 15U=2j*.b  
this.nStartPos = nStart; =q5A@!D  
this.nEndPos = nEnd; ,3GM'e{hV  
nThreadID = id; w^`n  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 |}q0G~l  
} d-N<VVcy\  
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public void run() D9H|]W~  
{ <ze'o.c  
while(nStartPos < nEndPos && !bStop) )CdglPK  
{ O:lD>A4{  
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try{ rIge6A>I  
URL url = new URL(sURL); *i%!j/QDAP  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 51;(vf  
httpConnection.setRequestProperty("User-Agent","NetFox"); do=VPqy
 
String sProperty = "bytes="+nStartPos+"-"; >PySd"u  
httpConnection.setRequestProperty("RANGE",sProperty); |.(o4<nx.  
Utility.log(sProperty); |nD2k,S<?  
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InputStream input = httpConnection.getInputStream(); @[ :sP  
//logResponseHead(httpConnection); VWfrcSZg6M  
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byte[] b = new byte[1024]; B}P,sFghw  
int nRead; eX_}KH-Q  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) tinN$o Xy  
{ 8
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nStartPos += fileAccessI.write(b,0,nRead); gdCU1D
\  
//if(nThreadID == 1) <,rjU
*"  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); {b/AOR o  
} b55|JWfC`  
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Utility.log("Thread " + nThreadID + " is over!"); 8 
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bDownOver = true; #C>pA<YJzK  
//nPos = fileAccessI.write (b,0,nRead); 1uXtBk6  
} Qr0JJoHT  
catch(Exception e){e.printStackTrace ();} JxD@y}ZYE  
} 'Fc&"(!||  
} $AsM 9D<BE  
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//打印回应的头信息 iNQk{n  
public void logResponseHead(HttpURLConnection con) $(zJ  
{ ZibHT:n  
for(int i=1;;i++) qM1$?U  
{ &LL81u6=S  
String header=con.getHeaderFieldKey(i); +p<Y)Z(>6  
if(header!=null) /;.M$}Z>`  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Xd|5{  
Utility.log(header+" : "+con.getHeaderField(header)); 3tLh{S?uJ  
else mDV 2vg  
break; ^Gd<miw  
} 9w0 ^=  
} 4-3
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public void splitterStop() {5%<@<?)  
{ `b7o  
bStop = true; 8o{ SU6pH  
} Q?1 KxD!  
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} ^?J:eB!  
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/* |}mBW@ah  
**FileAccess.java HPpnw]_  
*//文件访问(定位，写) 9d2$F9]:o  
package NetFox; ORHC bw9  
import java.io.*; d!wd,Xj}  
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public class FileAccessI implements Serializable{ Nxt/R%(  
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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 %%k[TO  
RandomAccessFile oSavedFile; np>*O}r*  
long nPos; jg
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public FileAccessI() throws IOException MPGQ4vi&  
{ 7rr5$,Mv  
this("",0); ZjI^0D8  
} <XLATS8Y  
|Xu7cCh$me  
 UNhD  
public FileAccessI(String sName,long nPos) throws IOException 9td(MZ%i~N  
{ k2;8~LqF  
oSavedFile = new RandomAccessFile(sName,"rw"); F%Mlid;1  
this.nPos = nPos; 9X*q^u  
oSavedFile.seek(nPos); .OWIlT4K  
} *aT!|;  
`\.n_nM  
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public synchronized int write(byte[] b,int nStart,int nLen) sY#K=5R  
{ hnY^Z_v!  
int n = -1; f9\7v_  
try{ E=
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oSavedFile.write(b,nStart,nLen); H+: $ 7;  
n = nLen; 5?I]\Tb  
} Icr'l$PE  
catch(IOException e) hi ]+D= S  
{ MBwp{ET!p  
e.printStackTrace (); Fvv6<
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} XSD7~X/:  
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2]C0d8=*?  
return n; }5S2v+zE  
} 4Fz^[L}[  
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} 
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> voUh;L  
/* 4^i*1&"  
**SiteInfoBean.java zf S<X  
*/ eVlI:yqppj  
package NetFox; #Gg^fm  
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public class SiteInfoBean { \Lc]6?,R  
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private String sSiteURL; //Site's URL k&?QeXW  
private String sFilePath; //Saved File's Path =AAH}  
private String sFileName; //Saved File's Name nv8,O=#s  
private int nSplitter; //Count of Splited Downloading File +,KuYa{lu  
+X- k)9  
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public SiteInfoBean() 1ii.nt1u  
{//nSplitter的缺省值为5 UHg^F4>4  
//default value of nSplitter is 5 Ri3m438  
this("","","",5); $Z,+aLmb  
} mee-Qq:}  
UU !I@  
!#?tA/t@  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) +tA rH C]  
{ 9wwvh'T&NK  
sSiteURL= sURL; ,on
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sFilePath = sPath; JBg>E3*N  
sFileName = sName; [[|;Wr}2  
this.nSplitter = nSpiltter; =o-qu^T^u  
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U
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} LTCj
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public String getSSiteURL() h?O-13v  
{ %Wu8RG}  
return sSiteURL; MdKZH\z/  
} :L?zk"0C  
Gm%[@7-  
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public void setSSiteURL(String value) 0I&rZMpF&  
{ pp-Ur?PM  
sSiteURL = value; Gah e-%J  
} _Yhpj}KZ  
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:I7MP  
public String getSFilePath() *V\kS  
{ h'}5"m  
return sFilePath; :G`_IB\  
} rm cy-}e  
1,mf]7k$  
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public void setSFilePath(String value) [|>.iH X  
{ msC
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sFilePath = value; W=b5{ 6  
} {jl4`  
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public String getSFileName() b6i0_fOO  
{ E=B9FIx~<  
return sFileName; COT;KC6 n  
} M-Js"cB[  
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public void setSFileName(String value) qzLRA.#f^  
{ vS0P]AUo  
sFileName = value; byMO&Lb*  
} r9%W?fEBp  
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public int getNSplitter() h>n;A>k@N  
{ }Yt0VtL
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return nSplitter; " c]Mz&z  
} 3HA{18{4uP  
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public void setNSplitter(int nCount) V- vVb  
{ 3Q#VD)  
nSplitter = nCount; B845BSmh  
} n-\B z.  
} s)N1@RBR  
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/* Oo0$n]*;W  
**Utility.java <E^:{J95  
*/ x?%vqg^r  
package NetFox; tsk}]@W  
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public class Utility { <wuP*vI"h  
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public Utility() >Kr,(8rA  
{ z(m*]kpL"  
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}C'z$i( y  
} 6>"0H/y,  
n% *u;iG  
//线程睡眠 gC3{:MC-G  
public static void sleep(int nSecond) ve.4""\a  
{ +F/'+  
try{ w&H ?;1  
Thread.sleep(nSecond); ;?y?s'>t&  
} $a-~ozr`C  
catch(Exception e) `KL`^UqR  
{ 8'?e4;O  
e.printStackTrace (); -r,J>2`l  
} =DtM.oQ>  
} xJ3#k;  
[$./'-I]  
//日志 E`X+fJx  
public static void log(String sMsg) EfyF]cYL  
{ dRu@5 :BP  
System.err.println(sMsg); NLdUe32A  
} E u@TCw8@  
>GjaA1,  
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public static void log(int sMsg) 8Yj(/S3y  
{ <Ei|:m  
System.err.println(sMsg); We9mkwK7C  
} bH=5[  
} `$i`i'S  
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/* J#D!J8KP7  
**TestMethod.java U{;i864:}  
*/ 8IX6MfR}C  
package NetFox; mxWaXb  
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public class TestMethod { ,mRN;|N  
qH-dT,`"{  
;hg]5r_  
public TestMethod() 1 t#Tp$  
{ ///xx/weblogic60b2_win.exe @^P=jXi<  
try{ Z^h4%o-l{  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); #v v k7  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); >N*QK6"=|  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 4];NX  
fileFetch.start(); h)YqC$A-s  
} q<7Nz]Td  
catch(Exception e){e.printStackTrace ();} #fFEo)YG  
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} ]vlQNd?  
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public static void main(String[] args) :H?p^d e  
{ p?!]sO1l  
new TestMethod(); r3KV.##u,  
} *mBEF"  
} yEz2F3[ S  
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