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http断点续传简单实现(java)

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/* RT~6#Caf  
**SiteFileFetch.java ,&q Q[i  
*/ U WU PY  
package NetFox; aANzL  
import java.io.*; A*a:#'"*N  
import java.net.*; YQ`m;<  
?xT ^9  
Qp5YS  
public class SiteFileFetch extends Thread { VQV%1f  
H wu (}  
B.oD9 <9  
SiteInfoBean siteInfoBean = null; //文件信息Bean @((Y[<  
long[] nStartPos; //开始位置 u&Lp  
long[] nEndPos; //结束位置 iiWm>yy  
FileSplitterFetch[] fileSplitterFetch; //子线程对象  (%\tE  
long nFileLength; //文件长度 )/Mk\``j  
boolean bFirst = true; //是否第一次取文件 *;0Ods+IcY  
boolean bStop = false; //停止标志 ^rX5C2}G\D  
File tmpFile; //文件下载的临时信息 H7}@56  
DataOutputStream output; //输出到文件的输出流 1oSU>I_i  
m+LP5S  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) .271at#-  
public SiteFileFetch(SiteInfoBean bean) throws IOException t91z<Y|  
{ \:pd+8  
siteInfoBean = bean; Vgg' 5o&.  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 9N*!C{VW  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); [Q:C\f]  
if(tmpFile.exists ()) f.{/PL  
{ c) q'" r  
bFirst = false; Mf_urbp]  
read_nPos(); }P(<]UF  
} Ae3=o8p  
else zAA3bgaa  
{ f$I$A(0P  
nStartPos = new long[bean.getNSplitter()]; }48 o{\  
nEndPos = new long[bean.getNSplitter()]; {@*l,[,5-  
} YX,xC-37y  
e{k)]]J  
\*i[m&3;q  
hI}rW^o^  
} tFrNnbmlQ  
[qHtN.  
Z-;I,\Y%  
public void run() 1_MaaA;ow"  
{ dkI(&/  
//获得文件长度 nR#'BBlI  
//分割文件 "}ZUa~7  
//实例FileSplitterFetch .J fV4!=o  
//启动FileSplitterFetch线程 #Ab,h#f*7  
//等待子线程返回 mJFFst,  
try{ ^oH!FN`;{  
if(bFirst) hY}.2  
{ 5 cz6\A&  
nFileLength = getFileSize(); M?G4k]  
if(nFileLength == -1) F0 ^kUyF|  
{ $?Z-BD1  
System.err.println("File Length is not known!"); csCi0'u  
}  FtmI\,  
else if(nFileLength == -2) NWt5)xl  
{ #1VejeTi  
System.err.println("File is not access!"); Y V#|qb  
} O od?ifA  
else 2dsXG$-W2  
{ +D+v j|fn  
for(int i=0;i<nStartPos.length;i++) v6U Gr4  
{ ~nJ"#Q_T  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); |)VNf .aJZ  
} HPMj+xH  
for(int i=0;i<nEndPos.length-1;i++) uG7?:) pxv  
{ d\ I6Wn  
nEndPos = nStartPos[i+1]; sU(<L0  
} bvW3[ V  
nEndPos[nEndPos.length-1] = nFileLength; ;fW`#aE  
} VTUSM{TC  
} A$g'/QM  
buldA5*!o  
lY&Sx{-  
//启动子线程 d>gQgQ;g  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; enGZb&  
for(int i=0;i<nStartPos.length;i++) (`&SV$m  
{ .[r1Qz7G  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), /HH_Zi0?N|  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), QE|x[?7e,!  
nStartPos,nEndPos,i); A("\m>g$b  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); k QF3DR$,B  
fileSplitterFetch.start(); x) jc  
} C2CR#b=)i  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +~>cAWZq_  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); NQxx_3*4O  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", e ?7y$H-  
nEndPos = " + nFileLength); eZ]>;5  
// fileSplitterFetch[nPos.length-1].start(); XU<XK9EA  
@Q7^caG  
: q>)c]  
//等待子线程结束 }hE!0q~MfM  
//int count = 0; ;qO3m -(d  
//是否结束while循环 75pn1*"gQ  
boolean breakWhile = false; % *ng *  
d\R "?Sg  
0Bt>JbGs4  
while(!bStop) wV\7  
{ N1}r%!jk/  
write_nPos(); DUSQh+C  
Utility.sleep(500); NFyV02.  
breakWhile = true; PWeWz(]0Z4  
xS(VgP&YGO  
i[4!% FxB  
for(int i=0;i<nStartPos.length;i++) z6Fl$FFP  
{ K8/jfm  
if(!fileSplitterFetch.bDownOver) ~|[i64V<^  
{ U'^ G-@  
breakWhile = false; T_q M@/f  
break; Pv=]7> e  
} !3<b#QAXRG  
} Aj]/A  
if(breakWhile) 'pyIMB?x  
break;  '[HBKn$`  
>7)QdaB  
V["'eJA,,  
//count++; /oZvm   
//if(count>4) XI:+EeM?  
// siteStop(); ~]24">VZf  
} nI4oQE  
.AQTUd(_  
;s#I b_  
System.err.println("文件下载结束!"); PdEPDyFkh  
} -aLM*nIoe  
catch(Exception e){e.printStackTrace ();} AQtOTT$  
} AHMvh 7O?  
mq}UUk@  
O 3?^P"C  
//获得文件长度 Lr20xm  
public long getFileSize() %__ @G_M  
{ Y O|hwhe_  
int nFileLength = -1; oB@)!'  
try{ FRL;fF  
URL url = new URL(siteInfoBean.getSSiteURL()); c (29JZ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); oGyoU#z#  
httpConnection.setRequestProperty("User-Agent","NetFox"); I?nU+t;  
mKE' l'9A_  
V lkJ$f5l  
int responseCode=httpConnection.getResponseCode(); ]T(qk  
if(responseCode>=400) {MN6JGb|'  
{ vXZP>  
processErrorCode(responseCode); V3T.EW  
return -2; //-2 represent access is error Q);}1'c  
} w11L@t[5W8  
ny!80I  
d|`8\fq  
String sHeader; @\:@_}Z`_}  
/cVZ/"  
TwF.UL@G%  
for(int i=1;;i++) OlptO60{ ]  
{ >) Bv>HM  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); [g}0.J`_  
//Utility.log(in.readLine()); :T>OJ"p  
sHeader=httpConnection.getHeaderFieldKey(i); 5Q:49S47  
if(sHeader!=null) f+.sm  
{ :c Er{U8  
if(sHeader.equals("Content-Length")) HX,i{aWWy  
{ w_;$ahsu~  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); b\kA  
break; sHV?njZd  
} "\]]?&  
} bYX.4(R  
else Z N&9qw*  
break; jK%Lewq  
} RE-y5.kE^  
} gKmF#Z"\  
catch(IOException e){e.printStackTrace ();} &" 5Yt&{  
catch(Exception e){e.printStackTrace ();} hBifn\dFr  
'Q=(1a11  
DeeV;?:  
Utility.log(nFileLength); }AiF 7N0  
ka{!' ^  
T.B7QAI. H  
return nFileLength; 5^CWF|  
} 9+8N-LZ  
oMYZ^b^  
g5x>}@ONq7  
//保存下载信息(文件指针位置) OB^j b8  
private void write_nPos() PCa0I^d  
{ 3Tc90p l*t  
try{ 1zCgPiAem  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 8o).q}>&  
output.writeInt(nStartPos.length); cK\?wZ| Y  
for(int i=0;i<nStartPos.length;i++) -D1 A  
{ o{l]n*  
// output.writeLong(nPos); jR+k x:+  
output.writeLong(fileSplitterFetch.nStartPos); ?iamo.0zN  
output.writeLong(fileSplitterFetch.nEndPos); 6(Ntt  
} V^>< =DNE  
output.close(); xJFcW+  
} {h.j6  
catch(IOException e){e.printStackTrace ();} 64<*\z_  
catch(Exception e){e.printStackTrace ();} 5Q8s{WQ  
} n;:C{5  
:2XX~|  
ta'wX   
//读取保存的下载信息(文件指针位置) 6?JvvS5  
private void read_nPos() S0LaQ<9.  
{ *<h)q)HS  
try{ 8.7lc2aX  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); }KNBqPo4B  
int nCount = input.readInt(); 2p58_^l  
nStartPos = new long[nCount]; qagR?)N)u  
nEndPos = new long[nCount]; <7gv<N6BQf  
for(int i=0;i<nStartPos.length;i++) ;hEeFJ=/G  
{ [8Z !dj   
nStartPos = input.readLong(); glBS|b$\:  
nEndPos = input.readLong(); nV8iYBBym  
} IP)%y%ycw  
input.close(); 8,e%=7h_e  
} <,U$Y>  
catch(IOException e){e.printStackTrace ();} j6L(U~%  
catch(Exception e){e.printStackTrace ();} 8kE3\#);\  
} =Tfm~+7nE  
c'5ls7?}O{  
WYkh'sv >  
private void processErrorCode(int nErrorCode) !!cN4X  
{ mrr -jo  
System.err.println("Error Code : " + nErrorCode); "g!ek3w(  
} .SNg2.  
C\^,+)Y\~  
rfr]bq5  
//停止文件下载 M)H*$!x}>  
public void siteStop() {A)9ePgv!  
{ 'q@vTM'-  
bStop = true; <\P `<  
for(int i=0;i<nStartPos.length;i++) vskp1Wi(  
fileSplitterFetch.splitterStop(); VSh&Y_%  
iqN?'8  
QFgKEUNgl  
} k^zU;  
}  k)W&ZY  
//负责部分文件的抓取 Ynp#3 r  
**FileSplitterFetch.java Vjd>j; H  
*/ y! QYdf?  
package NetFox; P?zaut  
W! J@30  
8xkLfN|N=  
import java.io.*; uf"(b"N0  
import java.net.*; 'u d[#@2  
io@f5E+?  
wzBw5n f\  
public class FileSplitterFetch extends Thread { wyXQP+9G  
J"TF@7{p  
bfy=  
String sURL; //File URL x0)WrDb  
long nStartPos; //File Snippet Start Position % iZM9Q&NC  
long nEndPos; //File Snippet End Position aK 3'u   
int nThreadID; //Thread's ID tf[)| /M  
boolean bDownOver = false; //Downing is over G&"O)$h  
boolean bStop = false; //Stop identical p./0N.  
FileAccessI fileAccessI = null; //File Access interface ;WgUhA ;q  
OB*V4Yv  
?/my G{E  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException G.PRPl  
{ NOKU2d4 G  
this.sURL = sURL; JV_VM{w{K  
this.nStartPos = nStart; 0sTR`Xk  
this.nEndPos = nEnd; Xg* ](>/\,  
nThreadID = id; mkl^2V13~  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 \N$)Q.M  
} $g/h=w@  
sRqecG(n  
0?dr(   
public void run() NCl@C$W9q  
{ s[t<2)i  
while(nStartPos < nEndPos && !bStop) 90K&oof?M  
{ ?Ygd|a5  
./L)BLC i  
MH9vg5QKp  
try{ )4m`Ya,E3  
URL url = new URL(sURL); Ivj=?[c|  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 8m=O408Q  
httpConnection.setRequestProperty("User-Agent","NetFox"); l5\V4  
String sProperty = "bytes="+nStartPos+"-"; ga(k2Q;y  
httpConnection.setRequestProperty("RANGE",sProperty); '$?!>HN4  
Utility.log(sProperty); KSHq0A6/q%  
`uH7~ r^  
[m%]C  
InputStream input = httpConnection.getInputStream(); DUh\x>^  
//logResponseHead(httpConnection); b6p'%;Y/  
b4WH37,lA  
T[#q0bv  
byte[] b = new byte[1024]; JodD6 ;P  
int nRead; F=e-jKogK  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) $*T?}r>  
{ x0:BxRx*  
nStartPos += fileAccessI.write(b,0,nRead); $mh\`  
//if(nThreadID == 1) c&FOt  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); v^vi *c  
}  Ip:54  
Poa&htxe1  
c+ByEP4EG  
Utility.log("Thread " + nThreadID + " is over!"); VpSpj/\m)'  
bDownOver = true; ^$sq U  
//nPos = fileAccessI.write (b,0,nRead);  bI8uw|c  
} ,v,rY'  
catch(Exception e){e.printStackTrace ();} 0;=- x"  
} >#k- ~|w  
} |_>^vW1f  
RAP-vVh/C  
Qh(X7B  
//打印回应的头信息 e}S+1G6r)  
public void logResponseHead(HttpURLConnection con) j49Uj}:j  
{ A`ajsZ{q,  
for(int i=1;;i++) ^|]Dg &N.  
{ q!?*M?Oz  
String header=con.getHeaderFieldKey(i); K +3=gBU*w  
if(header!=null) _lFw1pa#\  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); oPM*VTMA  
Utility.log(header+" : "+con.getHeaderField(header)); 8/BMFRJ  
else P(TBFu  
break; V 3cKbk7~  
} {svo!pN:  
} IT&,?u%  
T9H*]LxK  
3m` >D e  
public void splitterStop() 2R.L LE  
{ Zo yO[#  
bStop = true; _gI1rXI  
} hW< v5!,  
I4{xQI  
z+yIP ?s}(  
} ;ryNfP%  
&Xqxuy ]J  
ElV!C}g  
/* rUj\F9*5#  
**FileAccess.java *_o(~5w-K  
*//文件访问(定位,写) '=n?^EPE3  
package NetFox; |uqI}6h.  
import java.io.*; 6!\V|  
uy {O   
@+b$43 ^  
public class FileAccessI implements Serializable{ `MI\/oM@  
W=+n |1  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 xt^1,V4Ei~  
RandomAccessFile oSavedFile; RE>Q5#|c  
long nPos; ;'S,JGpvT  
\zBi-GI7  
#X-C~*|>j  
public FileAccessI() throws IOException >(RkoExO/  
{ ojM'8z 0Hn  
this("",0); .LDZqWr-  
} :r q~5hK  
 S_P&Fv  
50_[hC&C)  
public FileAccessI(String sName,long nPos) throws IOException HMd?`  
{ ;M~,S^U  
oSavedFile = new RandomAccessFile(sName,"rw"); Nf] ?hfJ  
this.nPos = nPos; v@\S$qU2  
oSavedFile.seek(nPos); KhR3$|fH<  
}  =yod  
poQ_r <I  
q;e b  
public synchronized int write(byte[] b,int nStart,int nLen) EH844k8 p  
{ MLd; UHU  
int n = -1; |Hf|N$  
try{ }097[-g7  
oSavedFile.write(b,nStart,nLen); ~@'wqGTp  
n = nLen; m9[ 7"I  
} Y<T0yl?  
catch(IOException e) S`s]zdUTP  
{ mx9vjW fy  
e.printStackTrace (); l[E^nh>  
} fu!T4{2  
v2x+_K}J  
q1rj!7  
return n; sQgz}0_= )  
} l#[Z$+!09  
IHEbT   
Kd oI  
} :?xH)J,imk  
$@Vn+| Ix  
# xO PF9  
/* GN_L"|#)=  
**SiteInfoBean.java _[[0rn$  
*/ Htgo=7!?\3  
package NetFox; mu\1hKq;B  
aU6l>G`w  
*}]#E$  
public class SiteInfoBean { BH'*I yv  
O i\ s  
ST{Vi';}  
private String sSiteURL; //Site's URL ,7wYa&  
private String sFilePath; //Saved File's Path 7^i7U-A<A  
private String sFileName; //Saved File's Name WWp MuB_G  
private int nSplitter; //Count of Splited Downloading File ZLzc\>QX  
=2$ ( tXL  
n3p@duC4  
public SiteInfoBean() 1{N+B#*<[X  
{//nSplitter的缺省值为5 CU|E-XPW  
//default value of nSplitter is 5 LzL)qdL  
this("","","",5); O[d#-0s  
} !H\;X`W|~D  
AFi_P\X  
O+W<l:|$  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) n$2oM5<  
{ *)RKU),3nL  
sSiteURL= sURL; nT?+^Ruc  
sFilePath = sPath; /xUF@%rT  
sFileName = sName; _;3,  
this.nSplitter = nSpiltter; ,ciX *F"  
,\i*vJ#f  
\Vme\Ke*v)  
} ]EHsRd  
jSpj6:@B  
6 rnFXZ\  
public String getSSiteURL() 2-@)'6"n  
{ Movm1*&=  
return sSiteURL; -+[Lc_oNPx  
} c>$d!IKCL  
HrE,K\^  
{ENd]@N*  
public void setSSiteURL(String value) A8tJ&O rwY  
{ }<~(9_+  
sSiteURL = value; (d#&m+ g]  
} Jk%5Fw0  
XQ=%a5w  
l)\Q~^cxd  
public String getSFilePath() x_~_/&X5  
{ _]@u)$  
return sFilePath; .I>rX#aNt  
} K+|XI|1p  
/)kJ iV  
O1~7#nJ*4[  
public void setSFilePath(String value) IoL P*D  
{ CJk"yW[,|  
sFilePath = value; VLV]e_D6s  
} |yz[mP*;o  
Pd+*syOM  
CmXLD} L_x  
public String getSFileName() O#k; O*s'  
{ >>$L vQ  
return sFileName; cO]w*Hti  
} b_`h2dUq  
hqln6m  
Pm6U:RL  
public void setSFileName(String value) C7F\Y1Wj  
{ :@)R@. -  
sFileName = value; K6-)l isf  
} "8%$,rG1&  
@k{q[6c2 n  
o@N[O^Q V  
public int getNSplitter() Dl.UbH }=  
{ 5wW5 n5YS  
return nSplitter; bM"?^\a&Q  
} @?e~l:g})g  
cz,CL/rno  
?{aC-3VAT  
public void setNSplitter(int nCount) :[+8(~| za  
{ 5eL b/,R  
nSplitter = nCount; g4k3~,=D3  
} ;%d<Uk?  
} 2FaCrc/  
m#_Rv  
E`.hM}h  
/* =v^#MU{k?  
**Utility.java YvN]7tcb  
*/ $)@D(m,ybd  
package NetFox; S'^ q  
FRR05%K  
=PY{Elf  
public class Utility { qE2VUEv5Y  
iJE:>qOTD5  
?o.d FKUe  
public Utility() ~tWh6-:|{J  
{ OU.}H $x"  
sgP{A}4 W  
~}j+~  
} G=[<KtWa  
O >+=cg  
//线程睡眠 y akRKiz\  
public static void sleep(int nSecond) o}G`t Bz  
{ , @UOj=  
try{ n_; s2,2r  
Thread.sleep(nSecond); *]HnFP  
} TW>GYGz  
catch(Exception e) ?2#'>B  
{ [m{sl(Q  
e.printStackTrace (); ~IW{^u  
} G\ F>*  
} 66F?exr  
U!-Nx9  
//日志 :,JjN&  
public static void log(String sMsg) Z5(9=8hB/  
{ hsY?og_H  
System.err.println(sMsg); o/7u7BQl2  
} XfE9QA[  
@ :Zk,   
9h6Oq(0b8  
public static void log(int sMsg) u$^tRz9  
{ N8pL2y:R[P  
System.err.println(sMsg); p&RC#wYu  
} G`n $A/9Q  
} >nSt<e  
Rs5lL-I  
l90"1I A  
/* LWJ ?p-X  
**TestMethod.java \Aro Sy9  
*/ cg3}33Z;6  
package NetFox; 2lsUCQI;  
1}a4AGAp  
~5&4s  
public class TestMethod { uEJ8Lmi  
$Z7:#cZ Y  
sUda   
public TestMethod() -eYL*Pa  
{ ///xx/weblogic60b2_win.exe ork|yj/A  
try{ 7S2c|U4IM  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ,$i<@2/=m  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); SbJh(V-pr  
SiteFileFetch fileFetch = new SiteFileFetch(bean); cX"G7Bh  
fileFetch.start(); _&mc8ftT  
} Z`"n:'&  
catch(Exception e){e.printStackTrace ();} Ey = 4 b  
"sIN86pCs  
(lWKy9eTy`  
} n@o  
C!kbZTO[p"  
\"bLE0~  
public static void main(String[] args) @ YrGyq  
{ G%`cJdM  
new TestMethod(); s|p(KWo2U  
} (T2<!&0 @  
} =KW|#]RB^  
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