http断点续传简单实现（java)

/* QAK.Qk?Qu  
**SiteFileFetch.java Jm{~H%  
*/ R:FyCT_,  
package NetFox; *EzAo  
import java.io.*; zP;1mN  
import java.net.*; x|IG'R1:Y  
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& wG3RR|  
public class SiteFileFetch extends Thread { -Drm4sTpDb  
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SiteInfoBean siteInfoBean = null; //文件信息Bean j,CMcP7A -  
long[] nStartPos; //开始位置 Mb[4G>-v=  
long[] nEndPos; //结束位置 PdD|3B&  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 yi9c+w)b  
long nFileLength; //文件长度 6P:H`  
boolean bFirst = true; //是否第一次取文件 ;3k6_ub  
boolean bStop = false; //停止标志 C
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File tmpFile; //文件下载的临时信息 `Ao;xOJ  
DataOutputStream output; //输出到文件的输出流 8L}N,6gC4_  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ?FRQ!R  
public SiteFileFetch(SiteInfoBean bean) throws IOException fl18x;^I  
{ u#m(Py  
siteInfoBean = bean; )#n>))   
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); !WReThq  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ^Wz3 q-^  
if(tmpFile.exists ()) [j`-R 0Np  
{ Cb/?hT  
bFirst = false; @5-+>\Hd^t  
read_nPos();  /,Sd  
} !saKAb}d7H  
else k&>l#oH  
{ JI}p{yI  
nStartPos = new long[bean.getNSplitter()]; S.Fip_  
nEndPos = new long[bean.getNSplitter()]; ]0wmvTR  
} 3tTz$$-#  
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} ~IE5j,SC  
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public void run() umWZ]8  
{ W<uL{k.Kpd  
//获得文件长度 6}6ky9  
//分割文件 ]m(5>h#  
//实例FileSplitterFetch T\h_8  
//启动FileSplitterFetch线程 v1j]&3O  
//等待子线程返回 xR,;^R|C  
try{ 'D4KaM.d  
if(bFirst) SEXLi8;/  
{ i#~1|2  
nFileLength = getFileSize(); 9N'um%J3%s  
if(nFileLength == -1) y'k4>,`9e  
{ 9/k?Lv  
System.err.println("File Length is not known!"); (dC<N3  
} &sx|sLw)  
else if(nFileLength == -2) |k4ZTr]?  
{ q61 rNOw_  
System.err.println("File is not access!"); =w.#j-jR  
} g loo].z  
else h;KI2k_^  
{ (A*r&Ak[  
for(int i=0;i<nStartPos.length;i++) V8xv@G{;  
{ 1% )M-io  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); /z4xq'<  
} xIo7f  
for(int i=0;i<nEndPos.length-1;i++) VrokEK*qbY  
{ }m<)$.x|P  
nEndPos = nStartPos[i+1]; dMwVgc:  
} [vaG{4m  
nEndPos[nEndPos.length-1] = nFileLength; `<>8tZS9"  
} A{E0 
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} Y4Z?`TL  
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//启动子线程 9CWUhS   
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; o+
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for(int i=0;i<nStartPos.length;i++) 8[FC  
{ *3
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), FJ}QKDQW=  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ':!;6v|L  
nStartPos,nEndPos,i); uu>[WFh  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 'eo2a&S2D  
fileSplitterFetch.start(); QLH s 3eM  
} t MB;GIb#  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 8}Y( @ %4  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); b}$m!c:<8  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Te>7I  
nEndPos = " + nFileLength); yg2~qa:dZ  
// fileSplitterFetch[nPos.length-1].start(); C({L4O#?o  
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_}!Q4K  
//等待子线程结束 j<+iL]b  
//int count = 0; .@APxeU  
//是否结束while循环 "MXd!  
boolean breakWhile = false; )}c$n  
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while(!bStop) !T0IMI  
{ RkLH}`#  
write_nPos(); XR\ iQ  
Utility.sleep(500); hBE}?J>  
breakWhile = true; <UQ:1W8>B  
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for(int i=0;i<nStartPos.length;i++) eOn,`B1  
{ fD\h5`-  
if(!fileSplitterFetch.bDownOver) df1* [  
{ u(ZS sftat  
breakWhile = false; 1"odkM  
break; BJj~fNm1Zr  
} 3 XfXMVm  
} SsznV}{^  
if(breakWhile) mk4%]t"  
break; jd2Fh):q  
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//count++; 'KQuz)-  
//if(count>4) g\(7z P  
// siteStop(); VY _(0  
} hkU# lt  
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System.err.println("文件下载结束！"); t41c
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} ?o.G@-  
catch(Exception e){e.printStackTrace ();} =,@SZsM*B  
} jQ`"Op 3  
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//获得文件长度 1C$^S]v%a  
public long getFileSize() D}"GrY5  
{ >;
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int nFileLength = -1; Y,(eu*Za  
try{ Tz*5;y%4  
URL url = new URL(siteInfoBean.getSSiteURL()); FxZ\)Y  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); uEi!P2zN  
httpConnection.setRequestProperty("User-Agent","NetFox"); Uero!+_  
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int responseCode=httpConnection.getResponseCode(); s*l_O*$'  
if(responseCode>=400) 2s{yg%U(  
{ R9CAw>s  
processErrorCode(responseCode); CYrL|{M]  
return -2; //-2 represent access is error _~cmR<  
} OC>" +  
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String sHeader; ;JmD(T7{  
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for(int i=1;;i++) 2hu6  
{ y~luuV;uj  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); &erNVD5o  
//Utility.log(in.readLine()); g{J3Ba  
sHeader=httpConnection.getHeaderFieldKey(i); 9M7P]$^  
if(sHeader!=null) ev?>Nq+Z  
{ d;;=s=j  
if(sHeader.equals("Content-Length")) ttw@nv% @  
{ _?r+SRFn  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 2d>PN^x  
break; ifgaBXT55  
} u\E.H5u27  
} 16Xwtn72  
else ]
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break; 1OGlD+f  
} NfO0^^"  
} FFQF0.@EBi  
catch(IOException e){e.printStackTrace ();} 2)8lJXM$L  
catch(Exception e){e.printStackTrace ();} k{bba=<  
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Utility.log(nFileLength); Va 5U`0  
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return nFileLength; v[|iuOU  
} n)=&=Uj`f  
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//保存下载信息（文件指针位置） 4YCGh
 
private void write_nPos() vn_avYwiy  
{ C}>&#)IH  
try{ S;c=6@"  
output = new DataOutputStream(new FileOutputStream(tmpFile)); drZw#b  
output.writeInt(nStartPos.length); =['ijD4TW  
for(int i=0;i<nStartPos.length;i++) ?)X@4Jem  
{ kU Flp  
// output.writeLong(nPos); Ww p^dx`!  
output.writeLong(fileSplitterFetch.nStartPos); uJO
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output.writeLong(fileSplitterFetch.nEndPos); j>T''Tf  
} @3@%9E  
output.close(); ?~K2&eo  
} Rk=B;  
catch(IOException e){e.printStackTrace ();} VO`A  
catch(Exception e){e.printStackTrace ();} DEs?xl]zO  
} S3<v?tqLr  
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//读取保存的下载信息（文件指针位置） 9j"\Lr*o"  
private void read_nPos() !eq]V9  
{
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try{ ;E&XFTdO  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); mOB\ `&h5  
int nCount = input.readInt(); R3PhKdQ"
 
nStartPos = new long[nCount]; c5;ROnTm  
nEndPos = new long[nCount]; e&5K]W0{  
for(int i=0;i<nStartPos.length;i++) kMo)4Xp  
{ 5Z[D(z  
nStartPos = input.readLong(); B<R-|-#  
nEndPos = input.readLong(); }rE|\p>  
} yU.0'r5uR  
input.close(); 7" [;M  
} #J!? :(m:  
catch(IOException e){e.printStackTrace ();} uS'ji k}  
catch(Exception e){e.printStackTrace ();} NIfc/%  
} #r:`bQ0;  
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private void processErrorCode(int nErrorCode) hvyN8We  
{ R}>Do=hAO  
System.err.println("Error Code : " + nErrorCode); :tqjm:  
} `9+EhP$RS  
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//停止文件下载 Em,!=v(*  
public void siteStop() v,+@ U6i  
{ >D<=9
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bStop = true; rd))H  
for(int i=0;i<nStartPos.length;i++) }'W^Ki$  
fileSplitterFetch.splitterStop(); uFm-HR@4  
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} $D5U
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} 2YKM9Ks  
//负责部分文件的抓取 cPcV[6)5K9  
**FileSplitterFetch.java 2M?lgh4"  
*/ Z?.*.<"Sj  
package NetFox; ib_Gy77Os  
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import java.io.*; s%oAsQ_y  
import java.net.*; -y?Z}5-rs  
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public class FileSplitterFetch extends Thread { )VMBo6:+  
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String sURL; //File URL 0 '7s  
long nStartPos; //File Snippet Start Position zD^f%p ["#  
long nEndPos; //File Snippet End Position cJEz>Z6[  
int nThreadID; //Thread's ID Oq,
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boolean bDownOver = false; //Downing is over $`{q[{  
boolean bStop = false; //Stop identical Hi_Al,j:  
FileAccessI fileAccessI = null; //File Access interface tR*W-%  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException lE)rRG+JLW  
{ xH_ie  
this.sURL = sURL; 4Qel;  
this.nStartPos = nStart; )O@^H  
this.nEndPos = nEnd;
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nThreadID = id; gAA %x7  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 s
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} -`dxx)x  
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public void run() fsJTwSI["  
{ [gkRXP[DGs  
while(nStartPos < nEndPos && !bStop) 5Vnr"d  
{ }gi1?a59  
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try{ ,}IER  
URL url = new URL(sURL); e0N=2i?I#z  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); A,lw-(.z4Z  
httpConnection.setRequestProperty("User-Agent","NetFox"); rfXF 01I  
String sProperty = "bytes="+nStartPos+"-"; $sc8)d\B  
httpConnection.setRequestProperty("RANGE",sProperty); 0|s$vqc  
Utility.log(sProperty); I0l.KiBm  
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InputStream input = httpConnection.getInputStream(); E8iadf49  
//logResponseHead(httpConnection); S?nNZW\6[  
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byte[] b = new byte[1024]; W}R=  
int nRead; XuFm4DEJ  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) W-C0YU1  
{ v[,v{5b  
nStartPos += fileAccessI.write(b,0,nRead); SJ@8
[n.x  
//if(nThreadID == 1) HV*:<2P%D  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); (ciGLfNG  
} 1FD7~S|  
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Utility.log("Thread " + nThreadID + " is over!"); ^i`3cCFB<  
bDownOver = true; SA`J.4yn  
//nPos = fileAccessI.write (b,0,nRead); |%:qhs,  
} VRd:2uDS  
catch(Exception e){e.printStackTrace ();} )WP]{ W)r  
} 2pxWv )0  
} }P&1s,S8J#  
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//打印回应的头信息 nj~$%vmA  
public void logResponseHead(HttpURLConnection con) uGP[l`f|FQ  
{ Io,/ +#|  
for(int i=1;;i++) fz<|+(_>J  
{ (sV]UGrZ  
String header=con.getHeaderFieldKey(i);
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if(header!=null) M]6w^\4j9  
//responseHeaders.put(header,httpConnection.getHeaderField(header));  r21?c|IP  
Utility.log(header+" : "+con.getHeaderField(header)); o7c%\v[  
else =9DhO7I'  
break; Z9J =vzsHE  
} 1kvPiV=X>  
} F1?CqN M  
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public void splitterStop() Pg*?[^*  
{ 3D?IG\3  
bStop = true; fB;&n  
} eEWroF  
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} ,-cpsN  
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/* hb 
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**FileAccess.java RlI W&y  
*//文件访问(定位，写) 'WKu0Yi^'  
package NetFox; D_l/Gxdpr  
import java.io.*; q5:0&:m$4$  
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public class FileAccessI implements Serializable{ `YFkY^T  
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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  aNOAu/  
RandomAccessFile oSavedFile; )^jQkfL  
long nPos; pX>ua5Z  
'+)6#/*  
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public FileAccessI() throws IOException &%|xc{i  
{ g2[K<  
this("",0); !pd7@FwC  
} X)FL[RO%q  
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public FileAccessI(String sName,long nPos) throws IOException KcIc'G 9  
{ "_nX5J9  
oSavedFile = new RandomAccessFile(sName,"rw");  )x$!K[=  
this.nPos = nPos; IT8B~I\OY  
oSavedFile.seek(nPos); sl~b\j  
} EsT0"{  
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public synchronized int write(byte[] b,int nStart,int nLen) iP~sft6  
{ Sp<hai  
int n = -1; K&j'c  
try{ D"`%|`O  
oSavedFile.write(b,nStart,nLen); .(`(chRa}  
n = nLen; NY~ dM\  
} b cC\  
catch(IOException e) V8-4>H}Cb/  
{ lKf Mp1  
e.printStackTrace (); 8&?^XcJ*x  
} s ;48v  
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}  
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return n; ; qO@A1Hq  
} BfX%|CWh  
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} 5fU!'ajaN7  
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/* %rFP#L  
**SiteInfoBean.java 1oB$MQoc  
*/ #X4LLS]VV  
package NetFox; Q%rVo4M#2  
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public class SiteInfoBean { &q.)2o#Q.  
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private String sSiteURL; //Site's URL MY&<)|v\  
private String sFilePath; //Saved File's Path 6KVV z/  
private String sFileName; //Saved File's Name g .3
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private int nSplitter; //Count of Splited Downloading File 2%bhW,?I  
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public SiteInfoBean() R j-jAH  
{//nSplitter的缺省值为5 m^z,,t9  
//default value of nSplitter is 5  /;+oz  
this("","","",5); 5Lw{0uLr  
} D
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) sb'lZFSP~s  
{ sbzeY1  
sSiteURL= sURL; 9-B@GFB;8  
sFilePath = sPath; 5qGGu.$Ihi  
sFileName = sName; gEE9/\>%-  
this.nSplitter = nSpiltter; ,dOMW+{  
vXc!Zg~  
/=b
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} cY{I:MA+h@  
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public String getSSiteURL()
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{ Kf|0*c  
return sSiteURL; (s&ORoVGn  
} g083J}08  
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public void setSSiteURL(String value) Vw7WK  
{ O /vWd"  
sSiteURL = value; 2f `&WUe  
}
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public String getSFilePath() -7
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{ j+nv=p  
return sFilePath; (p^S~Ax  
} gUspGsfr  
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public void setSFilePath(String value) O6/xPeak  
{ c+H)ed>  
sFilePath = value; wBLsz/  
} &u("|O)w$  
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public String getSFileName() V>
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{ PaNeu1cO  
return sFileName; ?x'w~;9R/  
} ~C0Pu.{o  
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public void setSFileName(String value) v
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{ =Aj"j-r&{  
sFileName = value; %oR>Uo  
} b1H7  
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public int getNSplitter() UPR/XQ  
{ ERp{gB2U?  
return nSplitter; w?*jdwh,'  
} ^zHRSO  
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;|;iCaD a+  
public void setNSplitter(int nCount) 1b8
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{ Jb9F=s+  
nSplitter = nCount; - {0g#G  
} 4Mi~1iZj  
} !M,h79NM  
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/* q1jN]H  
**Utility.java G8noQ_-  
*/ 2Sjt=LOc="  
package NetFox; ">cqt>2 A  
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public class Utility { )Y~xIj>  
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public Utility() 
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{ B2Qp}  
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} QE3ryD  
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//线程睡眠 <$Ztik1  
public static void sleep(int nSecond) &lq^dFP&Su  
{ + LS3T^  
try{ p0Z:Wkz]  
Thread.sleep(nSecond); #>XeR>T  
} ]
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catch(Exception e) %2}C'MqS  
{ EDtCNqBS~2  
e.printStackTrace (); viJJ e'\2  
} z(rK^RT  
} h07eEg  
/7x\;&bc  
//日志 HgaZbb>'  
public static void log(String sMsg) l1|~
 
{ }I]W'<jY  
System.err.println(sMsg); /h7.oD8CU  
} P2t_T'R}  
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public static void log(int sMsg) XddHP;x  
{ K0oFPDJN  
System.err.println(sMsg); :PUK6,"5]O  
} 6e<^oH  
} Gnk|^i;t  
A=y"x$%-_  
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/* VVFV8T4  
**TestMethod.java jWSb5#Pw  
*/ |Q5+l.%  
package NetFox; K\aAM
;)-  
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public class TestMethod { 2kVp_=c  
A4 5m)wQ  

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public TestMethod() 3p&jLFphL  
{ ///xx/weblogic60b2_win.exe ~#q;bS  
try{ ;:T9IL  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Z}+yI,  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 6"+8M 3M l  
SiteFileFetch fileFetch = new SiteFileFetch(bean); /BT1oWi1y  
fileFetch.start(); =U c$D*  
} <wa(xDBw  
catch(Exception e){e.printStackTrace ();} EX+,:l\^  
n]v7V&mj\  
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} =zOeb/  
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public static void main(String[] args) P5Dk63z]  
{ AEqq1A
 
new TestMethod(); }PZ=`w*O  
} 79wLT\&  
} B=dseeG[To  
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