http断点续传简单实现（java)

/* FT J{  
**SiteFileFetch.java ez5>V7Y  
*/ yMD0Tj5ZQ  
package NetFox; YNKvR  
import java.io.*; y|3("&)"S  
import java.net.*; *O)i)["  
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public class SiteFileFetch extends Thread { UQ@szE  
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SiteInfoBean siteInfoBean = null; //文件信息Bean \YF07L]qs-  
long[] nStartPos; //开始位置 ,^eOw
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long[] nEndPos; //结束位置 U%;E:|  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 A* Pz-z>z  
long nFileLength; //文件长度 NGO?K?  
boolean bFirst = true; //是否第一次取文件 nHp$5|r<  
boolean bStop = false; //停止标志 |Z+qaq{X  
File tmpFile; //文件下载的临时信息 r>CBp$  
DataOutputStream output; //输出到文件的输出流 aMJ2bu  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） t3K9 |8<  
public SiteFileFetch(SiteInfoBean bean) throws IOException x(~V7L>"i  
{ ]6O(r)k  
siteInfoBean = bean; (<}?}{YX0  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); dk]A,TB*2  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); IMzt1l =7  
if(tmpFile.exists ()) =e9<.{]S/  
{ a( N;|<  
bFirst = false; F|o1r  
read_nPos(); NdXC8  
} d5R2J:dI  
else UDnCHGq  
{ H6`zzH0"  
nStartPos = new long[bean.getNSplitter()]; F"3'~6  
nEndPos = new long[bean.getNSplitter()]; c+8 Y|GB  
} _x,(576~  
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} TB84}
  
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public void run() R"\(a  
{ #cb9g   
//获得文件长度 wjT#D|soI  
//分割文件 r/HG{XH`  
//实例FileSplitterFetch Ea0EG>Y  
//启动FileSplitterFetch线程 \nL@P6X  
//等待子线程返回 cHVu6I?h  
try{ 7_lgo6  
if(bFirst) .SOCWznb  
{ |W&K@g$  
nFileLength = getFileSize(); EZhk(LE  
if(nFileLength == -1) mGoC8t}iP  
{
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System.err.println("File Length is not known!"); P*hYh5a  
} bQI.Qk  
else if(nFileLength == -2) w6^TwjjZ$  
{ (Fq]y5  
System.err.println("File is not access!"); oU*e=uehj  
} Y ._Om}H  
else -B-HZ_  
{ C]ax}P>BQ  
for(int i=0;i<nStartPos.length;i++) M*~XpT3  
{ #]^M/y h  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); mJH4M9WJ]  
} [[]NnWJ  
for(int i=0;i<nEndPos.length-1;i++) &lxM
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{ LJt5?zQKrW  
nEndPos = nStartPos[i+1]; ,">CPl]  
} <7/7+_y  
nEndPos[nEndPos.length-1] = nFileLength; .t{uzDM  
} N%u4uLP5k  
} _eH@G(W(  
w[)HQ1K  
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//启动子线程 GpR,n2  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; %%h.`p1  
for(int i=0;i<nStartPos.length;i++) m93{K7O2e  
{ 2+R]q35-  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), uOZS
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), PMvm4<
  
nStartPos,nEndPos,i); RL/5o"  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); x_/H  
fileSplitterFetch.start(); 2_Cp}Pj  
} Lg2PP#r  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), WW7E*kc  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); DLe>EU;vS  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ]xIgP%  
nEndPos = " + nFileLength); c]ga)A(  
// fileSplitterFetch[nPos.length-1].start(); ww'B!Ml>F  
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d/YQ6oKU  
//等待子线程结束 =OKUSHu@V  
//int count = 0; L%pAEoSG  
//是否结束while循环 7&L8zl|K  
boolean breakWhile = false; >Tn[CgH]7  
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while(!bStop) m]{/5L  
{ ^lK!tOeO  
write_nPos(); yC!>7@m  
Utility.sleep(500); p-7?S^!l  
breakWhile = true; Us>
 
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4
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for(int i=0;i<nStartPos.length;i++) 9R&.$5[W(s  
{ B\;fC's+  
if(!fileSplitterFetch.bDownOver) PX?^v8wlqL  
{ ?~]mOv>  
breakWhile = false; 
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break; v)*eLX$  
} a"k,x-EL(  
} Ct3+ga$  
if(breakWhile) "#Q"gC.K  
break; u=(.}  
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//count++; ?b]f$ 2  
//if(count>4) ?9*[\m?-  
// siteStop(); .wtYostv  
} Nvd(Tad  
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System.err.println("文件下载结束！"); }j\8|UG  
} V9`jq$  
catch(Exception e){e.printStackTrace ();} &Mz.i,Gh  
} /[q_f  
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//获得文件长度 4k6:   
public long getFileSize() qJXfc||Zg  
{ |CBJ8],mT  
int nFileLength = -1; KF`m
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try{ hm1.UE  
URL url = new URL(siteInfoBean.getSSiteURL()); ;*20b@  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~AF' 6"A  
httpConnection.setRequestProperty("User-Agent","NetFox"); T7M];@q  
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int responseCode=httpConnection.getResponseCode(); X: Be'  
if(responseCode>=400) 
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{ a]I~.$G   
processErrorCode(responseCode); M%Q_;\?]  
return -2; //-2 represent access is error AJP-7PPD  
} gO]8hLT  

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+^4HCyW  
String sHeader; W9A F}  
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for(int i=1;;i++) ]v$2JgF]@  
{ #Jfmt~ks'  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); A5G@u}YS5  
//Utility.log(in.readLine()); )/bv@Am  
sHeader=httpConnection.getHeaderFieldKey(i); mWVq>~  
if(sHeader!=null) )Qo^Mz  
{ }9+Vf'u|l  
if(sHeader.equals("Content-Length")) RRGs:h@;  
{ krXU*64  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); u>2opI
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break; yJ8_<A  
} 9
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} TZObjSm_v  
else lhF)$M  
break; !@
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} 1Msc:7:L  
} 3gW+|3E  
catch(IOException e){e.printStackTrace ();} )fc+B
_  
catch(Exception e){e.printStackTrace ();} hWr}Uui  
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Utility.log(nFileLength); h-*h;Uyc  
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return nFileLength; nA+gqY6 6|  
} 1]7v3m  
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kyD*b3MN  
//保存下载信息（文件指针位置） NcIr; }  
private void write_nPos() k,r}X:<6jz  
{ Qgl5Jr.  
try{ k_ijVfI9  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Pm|S>r  
output.writeInt(nStartPos.length); NF_[q(k'  
for(int i=0;i<nStartPos.length;i++) 2K{)8;^  
{ !LpFK0rw  
// output.writeLong(nPos); ,.uI>  
output.writeLong(fileSplitterFetch.nStartPos); .gw6W0\F  
output.writeLong(fileSplitterFetch.nEndPos); 8oP"?ew#  
} x\5\KGw16  
output.close(); QV=|' S  
} <T$rvS  
catch(IOException e){e.printStackTrace ();} en16hd>^W:  
catch(Exception e){e.printStackTrace ();} AD"L
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} h{e?Fl  
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//读取保存的下载信息（文件指针位置） @P<Mc)o^  
private void read_nPos() `=I@W  
{ ],f%: ?%50  
try{ FW"gj\  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ? UBE0C  
int nCount = input.readInt(); 5Yx 7Q:D  
nStartPos = new long[nCount]; 257q%"  
nEndPos = new long[nCount]; ->&amPv
 
for(int i=0;i<nStartPos.length;i++) '\Uy;,tu /  
{ ;VgB!  
nStartPos = input.readLong(); Yg]!`(db  
nEndPos = input.readLong(); =UZm4=T  
}  h x hl  
input.close(); OJ)XJL  
} Cvtz&dH  
catch(IOException e){e.printStackTrace ();} iZ2nBiQ  
catch(Exception e){e.printStackTrace ();} R|!4k
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} N-Sjd%Z  
2?c%<_jPA  
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private void processErrorCode(int nErrorCode) ljk,R G  
{ >F;
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System.err.println("Error Code : " + nErrorCode); PKt;]T0  
} +HY.m+T  
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-
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//停止文件下载 m%i!;K"{s  
public void siteStop() jN sM&s,  
{ w#RfD  
bStop = true; gPy}.g{tH$  
for(int i=0;i<nStartPos.length;i++) !F#^Peb  
fileSplitterFetch.splitterStop(); e `IL7$  
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} e1 P(-V  
} =tqChw   
//负责部分文件的抓取 V%n7h&\%  
**FileSplitterFetch.java ~|=G3(I[  
*/ w)%/Me3o  
package NetFox; F ss@/-  
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import java.io.*; Rc`zt7hbJ  
import java.net.*; z6bIv}  
#|acRZ9 }  
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public class FileSplitterFetch extends Thread { d{RMX<;G  
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String sURL; //File URL -y)g}D%  
long nStartPos; //File Snippet Start Position OG2&=~hOz-  
long nEndPos; //File Snippet End Position wXUgxa  
int nThreadID; //Thread's ID LKu ,H  
boolean bDownOver = false; //Downing is over #:}mi;{  
boolean bStop = false; //Stop identical (Z at|R.F  
FileAccessI fileAccessI = null; //File Access interface ;%$wA5"2M  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException =-n7/  
{ 6g%~~hX
 
this.sURL = sURL; ,\0>d}eh!  
this.nStartPos = nStart; F;)qM|7  
this.nEndPos = nEnd; p(x<h  
nThreadID = id; 3Cl&1K #5  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 420yaw/":  
} 3("E5lI(g:  
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public void run() 2B=+p83<  
{ ,:?=j80m  
while(nStartPos < nEndPos && !bStop) jI,?*n<  
{ =
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try{ S *K0OUq  
URL url = new URL(sURL); qiyJ4^1  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Pxe7 \e  
httpConnection.setRequestProperty("User-Agent","NetFox"); LkUi^1((e  
String sProperty = "bytes="+nStartPos+"-"; qwHP8GU  
httpConnection.setRequestProperty("RANGE",sProperty); [35>T3Ku  
Utility.log(sProperty); <5sP%Fs)  
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InputStream input = httpConnection.getInputStream(); ny[\yj4F  
//logResponseHead(httpConnection); YEhPAQNj  
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byte[] b = new byte[1024]; y'U-y"7y  
int nRead; dmUa\1g#  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) _&/2-3]\B  
{ 6eAJ>9@x  
nStartPos += fileAccessI.write(b,0,nRead); =FXq=x%9+  
//if(nThreadID == 1) t{Gc,S!]5  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); \xexl1_;  
} _f<#+*y  
55vI^SSA  
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Utility.log("Thread " + nThreadID + " is over!"); +{"w5o<CO  
bDownOver = true; ]`_eaW?Ua  
//nPos = fileAccessI.write (b,0,nRead); RWINdJZ  
} 0;x<0P  
catch(Exception e){e.printStackTrace ();} 5Z(#)sa0Og  
} 7?"-NrW~  
}
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//打印回应的头信息 EF[I@voc  
public void logResponseHead(HttpURLConnection con) F`JW&r\  
{ qJT|om LY  
for(int i=1;;i++) -)Y[t Z^*`  
{ Dh B*k<S  
String header=con.getHeaderFieldKey(i); H(F9&6}  
if(header!=null) &=hkB9 ;  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); }X^CH2,R  
Utility.log(header+" : "+con.getHeaderField(header)); O(YvE  
else s!\Gi5b  
break; R)BH:wg"  
} -{s9PZ3~_  
} XT~]pOE;D  
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public void splitterStop() f&L8<ASFo  
{ $BWA=2$  
bStop = true; fd*<m8  
} ;0]s:0WD0P  
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} ()%;s2>F  
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/* Xrd-/('2  
**FileAccess.java T96M=?wh!  
*//文件访问(定位，写) P'D'+qS  
package NetFox; <<[\ Rv  
import java.io.*; -JfO} DRI  
anxwK47  
W`` 
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public class FileAccessI implements Serializable{ /D ~UK"}  
} {<L<  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 P~7p~ke  
RandomAccessFile oSavedFile; uT2w2A;  
long nPos; `Uy'YfYF  
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public FileAccessI() throws IOException NJ$c0CNy  
{ ?D S|vCae  
this("",0); 2kVQ#JyuRI  
} 6HR^q  
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public FileAccessI(String sName,long nPos) throws IOException 8$y5) ~Q  
{ i $;y  
oSavedFile = new RandomAccessFile(sName,"rw"); +a!uS0fIJi  
this.nPos = nPos; co
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oSavedFile.seek(nPos); Onj)AJ9M0r  
} mUjM5ceAXO  
o`}(1$a>  
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public synchronized int write(byte[] b,int nStart,int nLen) $J)2E g  
{ O>kM2xw  
int n = -1; 0rj50$~$]  
try{ rv;is=#1  
oSavedFile.write(b,nStart,nLen); 8u4FagQ,  
n = nLen; lko k2  
} $7'Kc
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catch(IOException e) G>w+J'7  
{ -VhxnhS  
e.printStackTrace (); Y<9]7R(\;  
} UZb!tO2  
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return n; L|
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} hT?|:!ED.F  
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} e]@R'oM?#`  
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/* wA?q/cw C  
**SiteInfoBean.java N/i {j.=  
*/ o`<ps$yT  
package NetFox; z<,rE  
]aTF0 R  
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public class SiteInfoBean { 4oA9|}<FR  
tB==v{t  
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private String sSiteURL; //Site's URL Xgyi}~AoaU  
private String sFilePath; //Saved File's Path Gfy9?sa  
private String sFileName; //Saved File's Name $61j_;WF`  
private int nSplitter; //Count of Splited Downloading File A~%h*nZc%I  
0>)F+QC  
gL}x|Q2`  
public SiteInfoBean() }Z3+z@L  
{//nSplitter的缺省值为5 *#g[ jl4  
//default value of nSplitter is 5 Ft^+P*  
this("","","",5); U t'r^  
} ]B>g~t5J  
ERZWK  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) !R@s+5P)U  
{ 2JX@#vQ4  
sSiteURL= sURL; D~LU3#n  
sFilePath = sPath; KG9FR*"  
sFileName = sName;
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this.nSplitter = nSpiltter; r"\g6<RP  
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} n06Jg+  
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public String getSSiteURL() ~ w,hJ `  
{ a0=>@?  
return sSiteURL; [[gfR'79{  
} x3]y*6  
 O)?  
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public void setSSiteURL(String value) Y4)v>&H  
{ .BjnV%l7Id  
sSiteURL = value; <Pg<F[eDM  
} TDR2){I  
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public String getSFilePath() Q3|I.I e  
{ lJ/{.uK  
return sFilePath; h(M
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} y~/i{a;1y  
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public void setSFilePath(String value) `6QQS3fk!  
{ l_z@.</8P@  
sFilePath = value; 6Z7J<0  
} VH2/  
=]<JkWSk  
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public String getSFileName() (X(c.Jj  
{ <Z^qBM  
return sFileName; ztHEXM.  
} RuuXDuu:VL  
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public void setSFileName(String value) &RbT&  
{ 'Bb@K[=s  
sFileName = value; pSh$#]mZ`  
} DY6ra% T  
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public int getNSplitter() k%fy  
{ ^#)M,.G^  
return nSplitter; EaXDY<  
} ug.'OR  
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public void setNSplitter(int nCount) BLQD=?Q
  
{ h(H b+7g  
nSplitter = nCount;
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} Jk3V]u  
} !-Br?  
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/* SdOE^_@:  
**Utility.java U)y~{E~c34  
*/ [V_?`M  
package NetFox; }$T!qMst{  
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public class Utility { X"pp l7o  
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public Utility() b"QeCw#v`>  
{ j~:N8(=  
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} HG)c\b  
$,L,VYN  
//线程睡眠 JU\wvP5j  
public static void sleep(int nSecond) .7Lv  
{ X*Dt<i};v  
try{ J~URv)g  
Thread.sleep(nSecond); KQ\d$fX  
} '-k~qQk)6  
catch(Exception e) <<:a>)6\  
{ XOi[[G}  
e.printStackTrace (); m"RE[dQ  
} >iIUS  
} ":upo/xN  
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//日志 Y%iimbBY|  
public static void log(String sMsg) BpQ/$?5E"  
{ 875BD U  
System.err.println(sMsg); Vn1hr;i]  
} Wr+1G 8  
RIQw+RG>  
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public static void log(int sMsg) %B{NH~  
{ &?@5G  
System.err.println(sMsg); wBK%=7  
} 999E0A$dkv  
} F6h|AF|"  
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>4lT0~V/  
/* _Z|3qQ  
**TestMethod.java rJ UXA<:2  
*/ ]A2l%V_7  
package NetFox; I N'a5&..  
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public class TestMethod { {Z=m5Dy}  
r$Z_Kwe.|&  
(~<9\ZJs  
public TestMethod() 6Wabw:  
{ ///xx/weblogic60b2_win.exe E-_Q3^
  
try{ /kY|PY  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); '9#O#I&J  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 3_]<H<w  
SiteFileFetch fileFetch = new SiteFileFetch(bean); k)a-odNrb  
fileFetch.start(); L--(Y+vmf  
} \%!~pfM I  
catch(Exception e){e.printStackTrace ();} \dz@hJl:  
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} i@C$O.m(  
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public static void main(String[] args) 01nbR+e  
{ "7k 82dw  
new TestMethod(); -OS&(7  
} u0(PWCi2
 
} d* 6 lJT  
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