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http断点续传简单实现(java)

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/* Up Z 9g"  
**SiteFileFetch.java +*OAClt+]  
*/ auI`'O`/  
package NetFox; s<*+=aIfu  
import java.io.*; we}xGb.u  
import java.net.*; v:lkvMq|=  
",apO  
A":=-$)  
public class SiteFileFetch extends Thread { ^a qQw u  
l#uF%;GDX  
"s@Hg1  
SiteInfoBean siteInfoBean = null; //文件信息Bean "= 2\kZ  
long[] nStartPos; //开始位置 27}:f?2hbJ  
long[] nEndPos; //结束位置 ?* ~4~ZE E  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 (YJ2- X~  
long nFileLength; //文件长度 H2iIBGu|L  
boolean bFirst = true; //是否第一次取文件 k8G4CFg}wP  
boolean bStop = false; //停止标志 PY|zN|  
File tmpFile; //文件下载的临时信息 ZQ"dAR/y  
DataOutputStream output; //输出到文件的输出流 I484c R2.  
5VE=Oo#&  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) .BjWZj  
public SiteFileFetch(SiteInfoBean bean) throws IOException B<~AUf*y  
{ wmpQF<  
siteInfoBean = bean; qKSR5 #  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); iK2f]h  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); WiH8j$;xu  
if(tmpFile.exists ()) y%|Ez  
{ aP(~l_  
bFirst = false; aGW O3Nk  
read_nPos(); N?3p,2  
} i`YZ;L L  
else 2V 8 "jc  
{ e O~p"d-|  
nStartPos = new long[bean.getNSplitter()];  Ju5Dd\  
nEndPos = new long[bean.getNSplitter()]; EFiVwH  
} $Ptl&0MN%  
{pQ8/Af!  
/.s L[X-G  
'`tFZfT  
} 5xT, O  
$[_5:@T%N  
<IU   
public void run() ,or;8aYc#  
{ [-`s`g-  
//获得文件长度 (4z_2a(Dl,  
//分割文件 Gy+c/gK  
//实例FileSplitterFetch yfwR``F  
//启动FileSplitterFetch线程 wo62R&ac  
//等待子线程返回 A99;bf}"  
try{ Zk7!CJVM  
if(bFirst) ;=0-B&+v  
{ P:J|![   
nFileLength = getFileSize(); }A6z%|d  
if(nFileLength == -1) m5/]+xdNX  
{ 3]iw3M  
System.err.println("File Length is not known!"); f7zB_hVDmE  
} V(XU^}b#  
else if(nFileLength == -2) Mmgm6{  
{ C-_u`|jQ  
System.err.println("File is not access!"); r:rPzq1  
} 5~>j98K  
else ~Y0K Wx4  
{ TN Z -0  
for(int i=0;i<nStartPos.length;i++) 1A93ol=  
{ A+Bq5mik  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); DZ`,QWuA  
} |+~P; fG  
for(int i=0;i<nEndPos.length-1;i++) O*2{V]Y @  
{ i Ya)*,  
nEndPos = nStartPos[i+1]; Lcg1X3$G  
} F" G+/c/L  
nEndPos[nEndPos.length-1] = nFileLength; \7UeV:3Ojn  
} 6ImW |%  
} }<z [t5  
Dd OK&  
8\)4waz$  
//启动子线程 3Zz_wr6  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; dr8Q>(ZY  
for(int i=0;i<nStartPos.length;i++) >y}> 5kv  
{ 7u1o>a %9  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), iyR5mA  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), g}?39?o4  
nStartPos,nEndPos,i); <%4pvn8d?&  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); sj+ )   
fileSplitterFetch.start(); TJcHqzcUc  
} SA"4|#3>7  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), PTpfa*t  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); "T8b.ng  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", V[8!ymi0  
nEndPos = " + nFileLength); lh\`9F:  
// fileSplitterFetch[nPos.length-1].start(); uI)z4Z  
+CQIm!Sp  
l7WZ" 6d  
//等待子线程结束 /w5c:BH  
//int count = 0; %}  
//是否结束while循环 ](+u'8  
boolean breakWhile = false; @Rd`/S@  
E)'T;%  
u#ocx[  
while(!bStop) '*U_!RmQ  
{ _0&U'/cs  
write_nPos(); rXrIGgeM  
Utility.sleep(500); .dc|?$XV  
breakWhile = true; 5n::]Q%=D  
M6[O> z  
j<?k$ 8H  
for(int i=0;i<nStartPos.length;i++) 8`<3rj  
{ bHDZ=Ik  
if(!fileSplitterFetch.bDownOver) ZSwhI@|  
{ ASS<XNP  
breakWhile = false; +>tSO!}[  
break; ,]@Sytky  
} YEiw!  
} %~<F7qB  
if(breakWhile) .L)j ql%  
break; eH;{Ln  
4{$ L]toP  
}y|_v^  
//count++; O/l/$pe  
//if(count>4) h?QGJ^#8  
// siteStop(); #E/|W T  
} 4SkCV  
EBmkKiI;  
?;rRR48T9E  
System.err.println("文件下载结束!"); w~AO;X*Ke"  
} JWQd6JQ_~V  
catch(Exception e){e.printStackTrace ();} SR4 mbQ:  
} j3o?B  
-9 |)O:  
rB =c  
//获得文件长度 pW<l9W  
public long getFileSize() EP{ji"/7[  
{ q ) e* eN  
int nFileLength = -1; :dlG:=.W  
try{ BE!WCDg,  
URL url = new URL(siteInfoBean.getSSiteURL()); H9=8nLb.  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 7U)w\A;~  
httpConnection.setRequestProperty("User-Agent","NetFox"); Qj9'VI>&  
SG)|4$"  
~. 5[  
int responseCode=httpConnection.getResponseCode(); n}J!?zZc  
if(responseCode>=400) 4g+o/+6!4  
{ ad<ZdO*h  
processErrorCode(responseCode); /p{$HkVw  
return -2; //-2 represent access is error w\>@> *E>  
} o3:h!(#G  
}vX 1@n7T6  
{>yy3(N  
String sHeader; .UUT@ w?  
2Gc0pBqx  
na|23jz4  
for(int i=1;;i++) )9 {!=k  
{ D' h%.  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); za5E{<0  
//Utility.log(in.readLine()); a;G>56iw  
sHeader=httpConnection.getHeaderFieldKey(i); 0fw>/"v  
if(sHeader!=null) Zx|VOl,;  
{ GS,}]c=  
if(sHeader.equals("Content-Length")) 1[(/{CClB  
{ l Ztw[c  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); _WBWFGj  
break; zE=^}K+  
} U;]h/3P  
} *5" )3\/  
else 2()/l9.O'  
break; rW2   
} ]2mfby  
} hhJ>>G4R2  
catch(IOException e){e.printStackTrace ();} (7|!%IO.  
catch(Exception e){e.printStackTrace ();} V}/AQe2m&  
R@[1a+}5  
AYoLpes  
Utility.log(nFileLength); AgJPtzs  
DLEHsbP{$  
K1*V\WRW5  
return nFileLength; 9t{Iv({6p  
} ghaO#kI  
tf{o=X.)  
<)$JA  
//保存下载信息(文件指针位置) 4#D>]AX  
private void write_nPos() Z7=k$e  
{ !?GW<Rh  
try{ LE+#%>z>  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 4^K<RSYs  
output.writeInt(nStartPos.length); jY $3   
for(int i=0;i<nStartPos.length;i++) pLpWc~#  
{ :w26d-QR(  
// output.writeLong(nPos); 3W@ta1  
output.writeLong(fileSplitterFetch.nStartPos); ?_@Mg\Hc  
output.writeLong(fileSplitterFetch.nEndPos); QjFE  
} CQET  
output.close(); 9y*pn|A[F  
} cG4$)q;q  
catch(IOException e){e.printStackTrace ();} BA`K,#Ft7  
catch(Exception e){e.printStackTrace ();} 6z1>(Za7>  
} <w0$0ku  
'zx1kq1  
q=/ck  
//读取保存的下载信息(文件指针位置) O.'\GM  
private void read_nPos() dQPW9~g8Hg  
{ PLQLGb4f_;  
try{ 6$\'dkufQ  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); `>\>'V<&  
int nCount = input.readInt(); @HP7$U"  
nStartPos = new long[nCount]; $McbVn)~f  
nEndPos = new long[nCount]; )uH#+IU  
for(int i=0;i<nStartPos.length;i++) Q|nGY:98  
{ F44KbUH  
nStartPos = input.readLong(); hdy N   
nEndPos = input.readLong(); Xs$UpQo  
} 0)9'x)l:  
input.close(); ]t.6bb4  
} cp3O$S  
catch(IOException e){e.printStackTrace ();} Aw7_diK^  
catch(Exception e){e.printStackTrace ();} Kd').w  
} S0p[Kt  
/\UFJ  
q,2 +\i  
private void processErrorCode(int nErrorCode) Q1u/QA:z7  
{ >WYradLUi  
System.err.println("Error Code : " + nErrorCode); HpR(DG) ?  
} ,(Nr_K  
s92SN F}g  
0tp3mYd  
//停止文件下载 +jGSD@32>  
public void siteStop() ])$Rw $`w  
{ %j2ZQ/z  
bStop = true; uxD$dd?  
for(int i=0;i<nStartPos.length;i++) Zf8_ko;|:-  
fileSplitterFetch.splitterStop(); 6,Y<1b*|Vo  
VgcLG ]tE[  
l5CFm8%  
} x10u?@  
} "DU1k6XC  
//负责部分文件的抓取 okQ<_1e{  
**FileSplitterFetch.java 5!iBKOl#D  
*/ a X:,1^  
package NetFox; /nVGr]t_pj  
h4k.1yH;  
I?Ct@yxhF'  
import java.io.*; b=Oec%Adx  
import java.net.*; I2<5#|CXpZ  
>sm<$'vZ/  
-)$5[jM]  
public class FileSplitterFetch extends Thread { )~H&YINhn  
+:#UU;W  
nx'Yevi0$  
String sURL; //File URL xHi.N*~D  
long nStartPos; //File Snippet Start Position m}o4Vr;"  
long nEndPos; //File Snippet End Position ;]sbz4?  
int nThreadID; //Thread's ID 31k2X81;a  
boolean bDownOver = false; //Downing is over Tt\G y  
boolean bStop = false; //Stop identical (|.rEaTA[1  
FileAccessI fileAccessI = null; //File Access interface [X\~J &kD  
O#B2XoZa+  
LV!<vakCK  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException HMPb%'U~  
{ DNy 6Kw  
this.sURL = sURL; vZ/Bzy@|  
this.nStartPos = nStart; a?ux  
this.nEndPos = nEnd; TjLW<D(i>  
nThreadID = id; Vs@H>97,G  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 qC ku q  
} acdF5ch@  
Hw 1cc3!  
Rr6}$]1  
public void run() g]E>e v{`  
{ CH+mzy  
while(nStartPos < nEndPos && !bStop) u#~q86k  
{ K *xca(6  
;{f4E)t 7  
qttJ*zu  
try{ 6PdLJ#LS  
URL url = new URL(sURL); xfADks2w  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); )HJ#|JpxC  
httpConnection.setRequestProperty("User-Agent","NetFox"); u5E\wRn  
String sProperty = "bytes="+nStartPos+"-"; t @vb3  
httpConnection.setRequestProperty("RANGE",sProperty); P&}J (;Lbl  
Utility.log(sProperty); `T(T]^C98  
?Oyps7hXx  
vG'I|OWg  
InputStream input = httpConnection.getInputStream(); b&\f 8xZ  
//logResponseHead(httpConnection);  "DsL$D2e  
8q_"aa,`  
/7jb&f   
byte[] b = new byte[1024]; m%)Cw)t 7  
int nRead; wC`+^>WFo  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) %+0V0.  
{ nX|]JW  
nStartPos += fileAccessI.write(b,0,nRead); '4]_~?&x  
//if(nThreadID == 1) =dDr:Y<@*  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); =@y ?Np^A  
} >N8*O3  
o GN*p_g  
m*H' Cb  
Utility.log("Thread " + nThreadID + " is over!"); l7vxTj@(-  
bDownOver = true; tiQeON-Q_  
//nPos = fileAccessI.write (b,0,nRead); ((cRe6  
} W}aCU~  
catch(Exception e){e.printStackTrace ();} lXOT>$qR<  
} qEajT"?  
} {dXmSuO  
}(/\vTn*1  
c 4Wl^E 8  
//打印回应的头信息 ?{rpzrc!*  
public void logResponseHead(HttpURLConnection con) cbaa*qoU  
{ $i]G'fj  
for(int i=1;;i++) AtYqD<hl:  
{ .-4]FGg3  
String header=con.getHeaderFieldKey(i); bd)'1;p  
if(header!=null) i$JN s)I%  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); X(JE]6_  
Utility.log(header+" : "+con.getHeaderField(header)); <tto8Y j  
else N977F$B o  
break; `Y_G*b.Rm  
} 8Ai\T_l  
} 7-A/2/G<  
WO!'("  
iph}!3f  
public void splitterStop() ?'RB'o~  
{ t+Au6/Dx?  
bStop = true; |*n B2  
} EaKbG>  
><i: P*ht  
E_-QGE/1  
} FW)VyVFmk  
_bn "c@s  
9>9,   
/* ?4cj"i  
**FileAccess.java \qz! v  
*//文件访问(定位,写) V_/.]zQA  
package NetFox; Y1R?, 5  
import java.io.*; hMnm>  
;b_l/T(  
/I &wh  
public class FileAccessI implements Serializable{ DPr~DO`b  
RmRPR<vGW  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 "/nbcQ*s*E  
RandomAccessFile oSavedFile; %&j \:X~A  
long nPos; sf"vii,1A  
r1 [c+Hy  
[,56oMd~  
public FileAccessI() throws IOException y;<F|zIm  
{ K$I`&M(  
this("",0); 7KL@[  
} WS//0  
-car>hQq  
+t%1FkI\  
public FileAccessI(String sName,long nPos) throws IOException o[)*Y`xq<w  
{ 3?e~J"WXC5  
oSavedFile = new RandomAccessFile(sName,"rw"); c8LMvL  
this.nPos = nPos; -G(#,rXk  
oSavedFile.seek(nPos); n?*r,)'  
} spT$}F2n  
>R}G  
K5!OvqzG  
public synchronized int write(byte[] b,int nStart,int nLen) dngG=  
{ M $f6. j  
int n = -1; !<>*|a  
try{ eZBC@y  
oSavedFile.write(b,nStart,nLen);  h@PE:=  
n = nLen; Ot`znJU@  
} 2Q5 -.2]  
catch(IOException e) AQwai>eL  
{ |k^C-  
e.printStackTrace (); -9Dr;2\  
}  :!Nx'F9a  
V1haAP[#  
z(Z7[#.  
return n; R@){=8%z  
} d hjX[7Bl9  
SY.ZEJcv  
<nTZs`$LwL  
} zx5#eMD  
|DYgc$2pN  
G=]ox*BY  
/* td7Of(k'  
**SiteInfoBean.java &0i$Y\g  
*/ Fw:_O2  
package NetFox; e07u@_'^  
>gDeuye  
WLA&K]  
public class SiteInfoBean { 3CH> !QOA  
fN/;BT  
(&Rql7](8  
private String sSiteURL; //Site's URL 7>=  
private String sFilePath; //Saved File's Path 0SQrz$y  
private String sFileName; //Saved File's Name pHXs+Ysw+  
private int nSplitter; //Count of Splited Downloading File P\WFm   
?) T@qn+  
@]!9;?so  
public SiteInfoBean() 6_:I~TTX  
{//nSplitter的缺省值为5 Fv*Et-8tN5  
//default value of nSplitter is 5 K|Eelhm  
this("","","",5); D5!#c-Y-  
} 1_};!5$.  
-y>~ :.  
<<b]v I  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter)  +#\7 #Y  
{ sF>O=F-7  
sSiteURL= sURL; 4jSYR#Hqp`  
sFilePath = sPath; W*%(J$E  
sFileName = sName; zdw* ?C  
this.nSplitter = nSpiltter; wX$|(Y }  
OADW;fj  
Ot)S\s>  
} G<* Iw>ep  
C1+f\A|9FP  
'4_c;](W  
public String getSSiteURL() >bd@2au9!  
{ ?4oP=.  
return sSiteURL; c/igw+L()  
} 7377g'jL  
8+J>jZ  
r6kJV4I=re  
public void setSSiteURL(String value) J.'%=q(Sb  
{ 8N+T=c  
sSiteURL = value; }%z%}V@(&  
} ;>L8&m)R5  
0ckmHv  
b kc*it  
public String getSFilePath() hNhEA $X5  
{ { 0-on"o  
return sFilePath; Ctn 4q'Q  
} z:$ibk4#h  
) P>/g*  
}Z{FPW.QK  
public void setSFilePath(String value) !l=)$RJKdD  
{ {z\K!=X/  
sFilePath = value; lZuH:AH  
} rwVp}H G  
reNf?7G+m  
d^J)Mhju  
public String getSFileName() PZ`11#bbm  
{ IxS%V31  
return sFileName; iPCCTs  
} 7~F~'V  
xQ7U$QF|]  
i/skU9  
public void setSFileName(String value) 1. +6x4%rV  
{ 3h:y[Vm#9y  
sFileName = value; gnjhy1o  
} 7F6 B  
/`7+Gy<  
Mn/@?K?y  
public int getNSplitter() 'A^q)hpax  
{ 92t.@!m`  
return nSplitter; ,oh;(|=  
} {?5iK1|}K  
! xG*W6IT  
\Dy|}LE  
public void setNSplitter(int nCount) PCHspe9!y  
{ )Z:D}r8[  
nSplitter = nCount; `:;q4zij;  
} /.<v,CR  
} Y#XRn _2D  
~mARgv  
gK9d `5  
/* !{ (Bc8 hT  
**Utility.java ?h&?`WO (  
*/ q :TNf\/o  
package NetFox; pm,xGo2  
8\!E )M|4  
BjsT 9?6W/  
public class Utility { qSB&Q0T  
WA"~6U*  
(nt`8 0  
public Utility() I](a 5i  
{ C[G+SA1&W  
|Rz.Pt6  
DegbjqZ#  
} O"+0 b|  
GaG>0 x   
//线程睡眠 8>,w8(Nt  
public static void sleep(int nSecond) `H6~<9r  
{ 3>-h- cpMX  
try{ #$- E5R;x  
Thread.sleep(nSecond); &.\7='$F  
} >#x[qX  
catch(Exception e) =uH2+9.  
{ {V2"Pym?  
e.printStackTrace (); *H/3xPh,*  
} y'`/^>.  
}  '2*OrY  
a @2fJ}  
//日志 [i /!ovcY  
public static void log(String sMsg) H{vKk  
{ lQHF=Jex  
System.err.println(sMsg); X<}}DZSu a  
} Ly+UY.v"  
_E`+0;O  
<3x%-m+p4  
public static void log(int sMsg) 32<D9_  
{ Qk:Lo*!  
System.err.println(sMsg); mGj)Zrx>  
} #~|k EGt  
} P,{Q k~iu  
PY.K_(D  
hOU H1m.  
/* 'UIFP#GtFO  
**TestMethod.java ovTL'j!  
*/ \X:e9~  
package NetFox; gCb+hQq\  
2URGd#{VQ  
&Mk!qE<:N  
public class TestMethod { ]=q auf>3  
_TOWqV^  
J8alqs7  
public TestMethod() + U5Q/g  
{ ///xx/weblogic60b2_win.exe w W@e#:  
try{ )N&SrzqTK  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); P3&s<mh  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ORs :S$Nt$  
SiteFileFetch fileFetch = new SiteFileFetch(bean); A _zCSRF,  
fileFetch.start(); BB/wL_=:  
} i D IY|  
catch(Exception e){e.printStackTrace ();} I?3b}#&V9  
KFd +7C9  
'F/oR/4,  
} h#hr'3bI1  
B>^6tdz  
n[iwi   
public static void main(String[] args) ^?`fN'!p  
{ Swhz\/u9  
new TestMethod(); \5r^D|Rp}  
} 9:USxFM  
} 't5ufAT  
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