http断点续传简单实现（java)

/* "0p +SZ~D  
**SiteFileFetch.java [J(@$Qix  
*/ 3^uL`ETm@  
package NetFox; ]=O{7#  
import java.io.*; =P@M&Yy'  
import java.net.*; 30wYc &H  
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public class SiteFileFetch extends Thread { &6=TtTp"9  
:Q0?ub]  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 'M]CZ}  
long[] nStartPos; //开始位置 i!/h3%=  
long[] nEndPos; //结束位置 &VtWSq-)  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 eHfG;NsV/  
long nFileLength; //文件长度 0jl:Yzo&\  
boolean bFirst = true; //是否第一次取文件 U)IsTk~}O  
boolean bStop = false; //停止标志 G~Q*:m  
File tmpFile; //文件下载的临时信息 fJ|Bu("N  
DataOutputStream output; //输出到文件的输出流 j};pv2  
dT*
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） qkZ5+2m  
public SiteFileFetch(SiteInfoBean bean) throws IOException ,Yiq$Z{qQ  
{ Gx~"iM  
siteInfoBean = bean; 3\+[38 _  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ^"6D0!'N  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); =l?"=HF  
if(tmpFile.exists ()) m,kvEQ3  
{ ZIGbwL  
bFirst = false; P5ESrZ@f  
read_nPos(); 4`EvEv$i  
}  \!' {-J  
else *cb D&R\  
{ ^|a&%wxA  
nStartPos = new long[bean.getNSplitter()]; _Oaso >  
nEndPos = new long[bean.getNSplitter()]; z?IY3]v*z<  
} }AeE|RNc  
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} eW }jS/g`  
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public void run() TnZc.  
{ %l]rQjV-  
//获得文件长度 Rp4BU"&sU  
//分割文件 j_YZ(: =  
//实例FileSplitterFetch m%[
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//启动FileSplitterFetch线程 wTgx(LtH  
//等待子线程返回 KzFs#rhpn  
try{ e4NX\tCpw  
if(bFirst) dA MilTo  
{ hnfrnYH  
nFileLength = getFileSize(); U mx  
if(nFileLength == -1) 6u]OXPA|  
{ _QtQPK\+  
System.err.println("File Length is not known!"); (w7cdqe  
} (^@;`8Dy8  
else if(nFileLength == -2) -^nQ^Td=j  
{ " :nVigw&  
System.err.println("File is not access!"); SJ|.% gn  
} N6 }i>";_;  
else b3HTCO-,fC  
{ iJp!ROI  
for(int i=0;i<nStartPos.length;i++) p=P0$P+KM  
{ OmUw.VH  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); %+OPas8C  
} gV.Pg[[1  
for(int i=0;i<nEndPos.length-1;i++) :92a34  
{ H
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nEndPos = nStartPos[i+1]; ]C:Ifh~  
} -r2qIt  
nEndPos[nEndPos.length-1] = nFileLength; AZ Lt'9UD  
} 2W-NCE%K)T  
} )^'B:ic  
t;~`Lm@hY  

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//启动子线程 X72X:"  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; R"kE5:  
for(int i=0;i<nStartPos.length;i++) ?Dp^dR  
{ v}*u[GWl]  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), g1!L. On  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), kp>Z/kt  
nStartPos,nEndPos,i); 7|eSvC  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); L}S4Zz18  
fileSplitterFetch.start(); S/:QVs  
} !5 :[XvI#  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), BNm va  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Y,Zv0-"  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", vgp%;-p(  
nEndPos = " + nFileLength); f?I *`~k  
// fileSplitterFetch[nPos.length-1].start(); D\&y(=fzf  
>u#VHaB  
I\6<)2j/L  
//等待子线程结束 5Cyjq0+  
//int count = 0; eu|q {p  
//是否结束while循环 Lj1 @yokB  
boolean breakWhile = false; >"{zrwNq  
,%G2>PBt  
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while(!bStop) P&`r87J  
{ zi[M{bm  
write_nPos(); v23Uh2[@Yy  
Utility.sleep(500); ffd3QQ  
breakWhile = true; \ OINzfbr  
c^gIK1f-  
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for(int i=0;i<nStartPos.length;i++) a-2 {x2O  
{ y%l#lz=6  
if(!fileSplitterFetch.bDownOver) QNwAuH T  
{ p+D6Z'B  
breakWhile = false; 8J U~Q  
break; 9yAu<a  
} eE_X
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} ?^5*[H  
if(breakWhile) {S(T1ua  
break; R*C+Yk)Tkt  
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^  
.g?,:$`0D?  
//count++; %-|q3 ^s  
//if(count>4) 4x=Y9w0?8  
// siteStop(); dph6aN(49  
} ;CBdp-BUj  
rL"k-5>fd  
!\4FIs&Qv  
System.err.println("文件下载结束！"); UH|.@7w  
} t+q`h3
 
catch(Exception e){e.printStackTrace ();} uNBhVsM6<  
} ') y~d  
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//获得文件长度 3<V!y&a  
public long getFileSize() U8z"{  
{ >f8,YisH  
int nFileLength = -1; 1`\kXaG  
try{ k@U`?7X  
URL url = new URL(siteInfoBean.getSSiteURL()); B(dL`]@Xm  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Tyl"N{ _  
httpConnection.setRequestProperty("User-Agent","NetFox"); Z+7S,M  
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int responseCode=httpConnection.getResponseCode(); v}D!  
if(responseCode>=400) hDsORh!i  
{ B35f5m7r  
processErrorCode(responseCode); WE]^w3n9  
return -2; //-2 represent access is error c Zr4  
} &nProzC  
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String sHeader; pC8i&_A  
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for(int i=1;;i++) )`-]nMc  
{ ` 454=3H  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 5yID%  
//Utility.log(in.readLine()); ]"6<"1)  
sHeader=httpConnection.getHeaderFieldKey(i); CG;D(AWR;  
if(sHeader!=null) )`^:G3w  
{ Ls{fCi/2F  
if(sHeader.equals("Content-Length")) i$bBN$<b<  
{ i\G3 u#  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Ui&$/%Z|  
break; qQ_QF
 
} V^i3:'  
} !Ao
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else 2Mda'T8  
break; kZNZ?A<D  
} nabN.Ly  
} x7?{*
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catch(IOException e){e.printStackTrace ();} x3 S
 
catch(Exception e){e.printStackTrace ();} e+[J9;g  
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Utility.log(nFileLength); w6_}] &F  
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return nFileLength; O
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} j*{bM{~T<  
V
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5z_)  
//保存下载信息（文件指针位置） [>;O'>  
private void write_nPos() 6D],275`J  
{ qJ@?[|2R  
try{ i*<,@*  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ,n*.Yq  
output.writeInt(nStartPos.length); r!S iR(  
for(int i=0;i<nStartPos.length;i++) e9d~Xi16KY  
{ !Xm:$KH  
// output.writeLong(nPos); _OY;SJ(  
output.writeLong(fileSplitterFetch.nStartPos); TI332,eL  
output.writeLong(fileSplitterFetch.nEndPos); O,cx9N  
}  J{y@ O  
output.close(); gT.-Cf{  
} 1 .M?Hp9i  
catch(IOException e){e.printStackTrace ();} |Xag:hof  
catch(Exception e){e.printStackTrace ();} ZLkJYZk  
} vXF\PMf  
md0=6< }P  
B:4u2/!5  
//读取保存的下载信息（文件指针位置） H2]I__t/u  
private void read_nPos() 1}6pq2  
{ yS*PS='P  
try{ _W;u Qg']  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); W.a/k7 p  
int nCount = input.readInt(); 3{ci]h`:y8  
nStartPos = new long[nCount]; PT;$@q8  
nEndPos = new long[nCount]; 3X:F9x>y  
for(int i=0;i<nStartPos.length;i++) )d(cXN-T  
{ %Y@3)  
nStartPos = input.readLong(); 3 *G=U  
nEndPos = input.readLong(); 6-3l6q  
} B$bsh.  
input.close(); ctZW7  
} s+[=nau('w  
catch(IOException e){e.printStackTrace ();} r#XDgZtI  
catch(Exception e){e.printStackTrace ();} %VMazlM
15  
} ql#K72s  
BjH(E'K[b  
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private void processErrorCode(int nErrorCode) &0#qy9wx  
{ ' 9,}N:p  
System.err.println("Error Code : " + nErrorCode); t3M/ThIE  
} eN$~@'w  
982$d<0%  
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//停止文件下载 pK3cg|}  
public void siteStop() T>c;q%A/  
{ ecHy. 7H  
bStop = true;  u(BYRB  
for(int i=0;i<nStartPos.length;i++) 1t)6wk N  
fileSplitterFetch.splitterStop(); '.iUv#j4Sh  
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} PH]q#/'  
} A$5T3j'  
//负责部分文件的抓取 j#*K[  
**FileSplitterFetch.java +`[$w<I  
*/ `S!`=26Z!  
package NetFox; w qsPGkJJ7  
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import java.io.*; E5o0^^  
import java.net.*; tHGK<rb  
8^^al!0K~  
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public class FileSplitterFetch extends Thread { aqMZ%~7  
3Mdg&~85  
^iGIF~J9  
String sURL; //File URL l/TH"z(  
long nStartPos; //File Snippet Start Position [X-Q{c4  
long nEndPos; //File Snippet End Position >V]>h&`  
int nThreadID; //Thread's ID D`LwW` 9  
boolean bDownOver = false; //Downing is over jReI+ pS  
boolean bStop = false; //Stop identical t'z]<7  
FileAccessI fileAccessI = null; //File Access interface N8KHNTb-M  
,@P3!|  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException xOkf9k_  
{ rp _G.C  
this.sURL = sURL; A$-{WN.W  
this.nStartPos = nStart; \,?yj  
this.nEndPos = nEnd; =B;)h  
nThreadID = id; K
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 0AaN  
} v+\E%H  
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k  
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public void run() V,>#!zUv  
{ D$j`+`  
while(nStartPos < nEndPos && !bStop) -5E<BmM  
{ 6/GhQ/T%D  
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try{ ag] nVE/  
URL url = new URL(sURL); GM@TWwG-B  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 
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httpConnection.setRequestProperty("User-Agent","NetFox"); u'=#~'6  
String sProperty = "bytes="+nStartPos+"-"; ^goS?p/z  
httpConnection.setRequestProperty("RANGE",sProperty); I{M2nQi  
Utility.log(sProperty); Muarryh}  
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InputStream input = httpConnection.getInputStream(); d`^@/1tO  
//logResponseHead(httpConnection); ,PY<AI^59  
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byte[] b = new byte[1024]; RzyEA3L'  
int nRead; RI%*5lM8;  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) }
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{ #?aR,@n  
nStartPos += fileAccessI.write(b,0,nRead); 8o~
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//if(nThreadID == 1) F.O2;M|x  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Jq.26I=  
} |>[w$  
4}8Xoywi1  
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Utility.log("Thread " + nThreadID + " is over!"); m@jOIt!<  
bDownOver = true; OY?uqP}c  
//nPos = fileAccessI.write (b,0,nRead); Wmp\J3  
} |rNm_L2  
catch(Exception e){e.printStackTrace ();} {5*+  
} VM-J^  
} 6C)OO"Bc  
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//打印回应的头信息 %zY3,4~  
public void logResponseHead(HttpURLConnection con) c-gaK\u}j}  
{ 6Q\n<&,{  
for(int i=1;;i++) X2o5Hc)l<  
{ g|2D(J  
String header=con.getHeaderFieldKey(i); Xf#uK\f  
if(header!=null) aHb,4 wY  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); !M}&dW2  
Utility.log(header+" : "+con.getHeaderField(header)); 4;%=ohD:!  
else :<nL9y jt  
break;  vlE#z  
} `GH6$\:  
} ^gv)[  
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F[9IHT6{  
public void splitterStop() /@on=~  
{ h~<#1'/<  
bStop = true; S,J'Z:spf  
} Z73 ysn}  
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} p61"a,Xc  
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/* f61
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**FileAccess.java A7ck-9dT/L  
*//文件访问(定位，写) !74*APPHR  
package NetFox; a!wPBJJ  
import java.io.*; Be?mIwc_g  
LgB}!OLQ  
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public class FileAccessI implements Serializable{ ,{YC|uB  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 }8 ,b;Q  
RandomAccessFile oSavedFile; R-Uj\M>  
long nPos; 7dxY07yu  
@p}H@#/u\  
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public FileAccessI() throws IOException YIjBKh  
{ OB5{EILej  
this("",0); T,jxIFrF  
} =]"[?a >  
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public FileAccessI(String sName,long nPos) throws IOException qAkx52v6  
{ )WuuU [(  
oSavedFile = new RandomAccessFile(sName,"rw"); i Ri1E;  
this.nPos = nPos; J6\<>5A?  
oSavedFile.seek(nPos); \:^$ZBQr<n  
} W._vikR  
rt t?4  
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public synchronized int write(byte[] b,int nStart,int nLen) )HR'FlxOd  
{ F;`es%8  
int n = -1; :|P"`j  
try{ &ViIxJZ1$  
oSavedFile.write(b,nStart,nLen); ;LthdY()n(  
n = nLen; h&.9Q{D  
} tz._*n83  
catch(IOException e) 4Uz6*IQNl  
{ p8o%H-Xk
 
e.printStackTrace (); @v@'8E Q  
} ?=f\oH$  
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return n; ;/>~|@  
} T3wR0,  
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} W
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/* 
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**SiteInfoBean.java ';zLh  
*/ j&[63XSe  
package NetFox; sRt|G  
|M0 XLCNd_  
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public class SiteInfoBean { l.fNkLC#  
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private String sSiteURL; //Site's URL Br1JZHgA  
private String sFilePath; //Saved File's Path 7u o4F=%  
private String sFileName; //Saved File's Name DEqk9Exk`  
private int nSplitter; //Count of Splited Downloading File ]^ZC^z;H  
3J%jD  
_ 4Hf?m7z  
public SiteInfoBean() Ba!`x<wa  
{//nSplitter的缺省值为5 rx|/]NE;  
//default value of nSplitter is 5 [Z~>7ayF+)  
this("","","",5); 6L'cD1pu  
} w[:5uo(  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter)
o NJ/AT  
{ nPvR  
sSiteURL= sURL; klv^310  
sFilePath = sPath; Ya304Pjd  
sFileName = sName; x/bO;9E%U4  
this.nSplitter = nSpiltter; $P4hNb  
Lu1>A {et  
nLdI>c9R  
} =xai 7iM  
9bqfZ"6nXY  
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public String getSSiteURL() M/Bn^A8@  
{ N[dhNK"  
return sSiteURL; 7-6_`Q2}Y  
} ~A>3k2N/e  
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public void setSSiteURL(String value) ;y4 "wBX  
{ F RS@-P  
sSiteURL = value; cg$7`/U  
} A-c3B+  
k3^S^Bv\  
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public String getSFilePath() (p^q3\
 
{ 1UxRN7  
return sFilePath; c|96;=z~  
} \HTXl]  
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Il*wVNrZI  
public void setSFilePath(String value) E83{4A4  
{ HO&#Lv  
sFilePath = value; rs 7R5 F  
} %|l*=v  
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public String getSFileName() u_zp?Nc  
{ vF1]L]z:?  
return sFileName; g0_8:Gs}^  
} a2o+tR;H  

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public void setSFileName(String value) /38^N|/Zr  
{ l(%bdy  
sFileName = value; $p}7CP  
} {@B<$g   
#}e)*(  
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public int getNSplitter() O8 k$Uc  
{ MP0gLi  
return nSplitter; b[$l{RQ[?  
} 0u-'{6  
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[ V/*{Z  
public void setNSplitter(int nCount) 5BTQJa  
{ 8(5}Jo+  
nSplitter = nCount; }|AUV  
} Dgp"RUP  
} m_' 1yX@  
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/* V\X.AGc  
**Utility.java ~/iE  
*/ {p1#H`  
package NetFox; 1Cp5a2{  
^Shz[=fd  
GC#3{71  
public class Utility { 6\/C]![%  
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public Utility() _z{:Q  
{ O .m;a_  
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1+.(N:) +  
} 2c_#q1/Z/  
()=  
//线程睡眠 |*i0h`a  
public static void sleep(int nSecond) I[@}+p0  
{ QcIa%lf  
try{ *<"xF'C  
Thread.sleep(nSecond); y]+i.8[  
} ixE72bX  
catch(Exception e) Y(-4Agq  
{ _;L9&>!p6  
e.printStackTrace (); j#Bea ,  
} ,eF}`  
} uiPfAPZ  
W`C2zbC  
//日志 T&fqn!i  
public static void log(String sMsg) 7%&#V2  
{ ~OAST  
System.err.println(sMsg); |!aMj8i2  
} RxjC sjg  
R'uM7,7  
"U4Sn'&h@  
public static void log(int sMsg) E#Smi507p  
{ ~(~fuDT~O  
System.err.println(sMsg); wtu WzHrF  
} r**u=q%p  
} p.SEW5  
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^%VMp>s
 
/* FrIguk1  
**TestMethod.java R0B\| O0Uv  
*/ C1:efa<wV  
package NetFox; U^-:qT;CX  
2,{m>fF  
%V%*0S|U  
public class TestMethod { D'$ki[{,  
CE=&ZHt9  
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public TestMethod() sk5h_[tK  
{ ///xx/weblogic60b2_win.exe NuRxkeEO  
try{ dq+VW}[EO  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); U3}r.9/  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); MDZ,a0?4t  
SiteFileFetch fileFetch = new SiteFileFetch(bean); lfba   
fileFetch.start(); y'?ksow  
} Q=}p P*  
catch(Exception e){e.printStackTrace ();} &U^6N+l9  
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} 7s+3^'  
~Gx"gK0  
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public static void main(String[] args) o?BcpWp  
{ uH!uSB2  
new TestMethod(); TPEg>[  
} rtd&WkU rD  
} KAVe~j"  
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