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http断点续传简单实现(java)

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/* Ywo=w:'  
**SiteFileFetch.java qCI0[U@  
*/ (RBB0CE  
package NetFox; 2~ y<l  
import java.io.*; = tY%k!R  
import java.net.*; p;<aZ&@O  
G Tz>}@W  
G2s2i2& 6E  
public class SiteFileFetch extends Thread { \ ^3cNw  
M!b-;{;'  
] ]lN[J  
SiteInfoBean siteInfoBean = null; //文件信息Bean P_F0lO  
long[] nStartPos; //开始位置 AkEt=vI  
long[] nEndPos; //结束位置 N+zR7`AG8  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ,CP&o  
long nFileLength; //文件长度 U1=]iG<%  
boolean bFirst = true; //是否第一次取文件 C,) e7  
boolean bStop = false; //停止标志 KN:V:8:J  
File tmpFile; //文件下载的临时信息 H03R?S9AQ  
DataOutputStream output; //输出到文件的输出流 m~`f0  
 +wE>h>?;  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) C[[:/X(c  
public SiteFileFetch(SiteInfoBean bean) throws IOException ,xg(F0q  
{ <.U(%`|  
siteInfoBean = bean; W0LJ Xp-v  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); t $u.  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); UW],9r/PD@  
if(tmpFile.exists ()) *d}{7UMy#  
{ Og:aflS  
bFirst = false; 1v'|%B;O  
read_nPos(); 4Ep6vm X  
} L[. )!c8k  
else S20E}bS:>  
{ #RWmP$+#=  
nStartPos = new long[bean.getNSplitter()]; nq*D91Q  
nEndPos = new long[bean.getNSplitter()]; d$PQb9Q+f  
} #F:\_!2c  
zxy/V^mu  
Ht7v+lY90^  
QV_Ep8  
} PHg(O:3WG  
S,GM!YZg  
mO @Sl(9  
public void run() x}jiHV@=  
{ ZnRE:=  
//获得文件长度 [OwrIL  
//分割文件 {AO`[  
//实例FileSplitterFetch &` weW  
//启动FileSplitterFetch线程 5`f\[oA  
//等待子线程返回 csms8J  
try{ Wf9K+my  
if(bFirst) --g? `4  
{ i&zJwUr(<  
nFileLength = getFileSize(); ez^b{s`  
if(nFileLength == -1) 5dEek7wnf  
{ ^A;(#5A]7  
System.err.println("File Length is not known!"); k4BiH5\hA  
} ~n9-  
else if(nFileLength == -2) <UBB&}R0  
{ R\>=}7  
System.err.println("File is not access!"); )! C|DSw  
} d;LBV<Z?  
else ]?j[P=\  
{ D(^ |'1  
for(int i=0;i<nStartPos.length;i++) tCbn B  
{ tC'@yX  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ~0ZLaiJ  
} a?ii)GGq  
for(int i=0;i<nEndPos.length-1;i++) I DtGtkF  
{ O^I%Xk  
nEndPos = nStartPos[i+1]; 7Jvb6V<R  
} qC$h~Epp4  
nEndPos[nEndPos.length-1] = nFileLength; So\f [/em  
} a>/jW-?  
} % .n 7+  
4f{(Scg  
S!wY6z  
//启动子线程 qra5&Fvb  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; H:&|q+K=#  
for(int i=0;i<nStartPos.length;i++) L?p,Sy<RI  
{ ]U,f}T"e  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), *O@uF4+!1  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Q )b*; @  
nStartPos,nEndPos,i); iPoDesp  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); En]+mIEo  
fileSplitterFetch.start(); ,c\3b)ax  
} "lJ [H=\  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), H3Z"u  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); X6lR?6u%|  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", CUo %i/R  
nEndPos = " + nFileLength); -H;p +XAY  
// fileSplitterFetch[nPos.length-1].start(); D/=  AU  
_laLTP*  
t/9,JG  
//等待子线程结束 (`pd>  
//int count = 0; V=g<3R&  
//是否结束while循环 Q~p[jQ,4wZ  
boolean breakWhile = false; h#iFp9N  
E5}wR(i,4  
<M4Qc12jP  
while(!bStop) j. L`@  
{ z|gG%fM  
write_nPos(); yIdM2#`u  
Utility.sleep(500); kTLA["<m  
breakWhile = true; (YJ]}J^  
+ ^9;<>P  
]JXpe]B  
for(int i=0;i<nStartPos.length;i++) Tpv]c  
{ bl)iji`]  
if(!fileSplitterFetch.bDownOver) &E>zvRBQ  
{ jGtoc,\X  
breakWhile = false; dU~DlaEy(  
break; <2Qh5umQ  
} 'h6Vj6  
} "c  S?t  
if(breakWhile) @?GOOD_i  
break; Tmo+I4qoL  
I=,u7w`m  
9x~qcH%  
//count++; jR^>xp;  
//if(count>4) nFn@Z'T$N  
// siteStop(); [We(0wF[`  
} m_7)r  
'42P=vzo  
l|[8'*]r!  
System.err.println("文件下载结束!"); #]yb;L  
} "/)}Cc,L  
catch(Exception e){e.printStackTrace ();} 9 xvE?8;M#  
} [p +h b  
bm{L6D E  
&S.zc@rN  
//获得文件长度 'CDRb3w}B  
public long getFileSize() Q-[^!RAK?  
{ U+!H/R)(  
int nFileLength = -1; ]Qp0|45=  
try{ 9's/~T  
URL url = new URL(siteInfoBean.getSSiteURL()); -4p^wNR  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ;mXr])J  
httpConnection.setRequestProperty("User-Agent","NetFox"); :v k+[PzJ  
:;u~M(R  
]FLuiC  
int responseCode=httpConnection.getResponseCode(); )>)_>[  
if(responseCode>=400) Cm;WQuv@  
{ B 0%kq7>g  
processErrorCode(responseCode); 2#nn}HEOC  
return -2; //-2 represent access is error '|e5cW6z  
} ;APpgt4  
DVYY1!j<  
q_8qowu"  
String sHeader; K \}xb2s  
yZaQ{]"  
35yhe:$nf  
for(int i=1;;i++) Vkex&?>v$  
{ #jV6w=I  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); voaRh@DZ%/  
//Utility.log(in.readLine()); &X^~%\F:2  
sHeader=httpConnection.getHeaderFieldKey(i); 8zz-jk R  
if(sHeader!=null) FXFQ@q*}v  
{ 0[0</"K%1m  
if(sHeader.equals("Content-Length"))  @4_CR  
{ LX j Tqp'  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 6^['g-\2  
break; ;W#G<M&n'  
} *#EyfMz-B  
} c0Jf  
else n$}c+1   
break; 0;OpT0  
} W.o W =<  
} z@&_3 Gl  
catch(IOException e){e.printStackTrace ();} ;4XX8W1  
catch(Exception e){e.printStackTrace ();} G\TyXq_4  
jKQnox+=  
g}' "&Y  
Utility.log(nFileLength); =bf-+gZD  
O" ['.b  
bQ0m=BzF  
return nFileLength; b#k$/A@  
} fYx$3a.  
!e.@Xk.P6  
&e_M \D  
//保存下载信息(文件指针位置) G?=X!up(  
private void write_nPos() ^']xkS  
{ ^fS~va  
try{ 1NN99^ q  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ~|Gtm[9Ru  
output.writeInt(nStartPos.length); F:IG3 @  
for(int i=0;i<nStartPos.length;i++) VILzx+v M  
{ s qac>v  
// output.writeLong(nPos); :(A]Bm3  
output.writeLong(fileSplitterFetch.nStartPos); &OGY?[n  
output.writeLong(fileSplitterFetch.nEndPos); qN+ngk,:  
} 8*4X%a=Of  
output.close(); E+>Qpy  
} v2JC{XqrI  
catch(IOException e){e.printStackTrace ();} &bs/a] ?Z7  
catch(Exception e){e.printStackTrace ();} +Medu?K `  
} N}VKH5U|  
-`iZBC50  
}I,]"0b  
//读取保存的下载信息(文件指针位置) RjSVa.x  
private void read_nPos() IR(JBB|xNQ  
{ l5D8DvJCj  
try{ =|pQA~UU#  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); hUB _[#8#  
int nCount = input.readInt(); J03yFT,dF  
nStartPos = new long[nCount]; W84JB3p  
nEndPos = new long[nCount]; l>7`D3  
for(int i=0;i<nStartPos.length;i++) /u*((AJ?Qv  
{ & 2>W=h  
nStartPos = input.readLong(); 5Ee%!Pk  
nEndPos = input.readLong(); 1nX/5z_U  
} )g9Zw_3  
input.close(); { >bw:^F  
} L @t<%fy@  
catch(IOException e){e.printStackTrace ();} vv"_u=H  
catch(Exception e){e.printStackTrace ();} DZilK:  
} j1Q G-Rs&  
ujmO'blO  
vtv|H  
private void processErrorCode(int nErrorCode) %mt|Dl  
{ lBgf' b3$  
System.err.println("Error Code : " + nErrorCode); loLQ@?E  
} 5|9,S  
1<\@i{;xsU  
SQ1.jcWW[  
//停止文件下载 co|jUDu>W  
public void siteStop() 4T{+R{_Y1  
{ (UA a  
bStop = true; &Op, ?\   
for(int i=0;i<nStartPos.length;i++) $ [by)  
fileSplitterFetch.splitterStop(); (es+VI2!&C  
9H_2Y%_  
o6 'I%Gs  
} \&NpVH,-  
} )~rf x  
//负责部分文件的抓取 {W)Kz_  
**FileSplitterFetch.java hJ (Q^Z  
*/ \j+O |#`|)  
package NetFox; +%OINMo.A  
9gZMfP  
C\ZL*,%}  
import java.io.*; 0~iC#lHO  
import java.net.*; d(3F:dbk  
r/$+'~apTk  
j&6,%s-M`a  
public class FileSplitterFetch extends Thread { '_lyoVP  
1XSA3;ZEc  
GbFLu`Iu  
String sURL; //File URL *p`0dvXG2  
long nStartPos; //File Snippet Start Position 5Q#;4  
long nEndPos; //File Snippet End Position gbsRf&4h  
int nThreadID; //Thread's ID %0fF_OU  
boolean bDownOver = false; //Downing is over Dd-;;Y1C  
boolean bStop = false; //Stop identical w,bILv)  
FileAccessI fileAccessI = null; //File Access interface o@>{kzCx  
nfJ|&'T  
A[oLV"J6x5  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 1+~JGY#   
{ ;2Db/"`t  
this.sURL = sURL; G~1#kg  
this.nStartPos = nStart; D9zw' R Y  
this.nEndPos = nEnd; zpV@{%VSj  
nThreadID = id; ~=h]r/b< U  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 l+Dl~o}  
} J]UlCg  
3UU]w`At  
v_)a=I%o&2  
public void run() \HLI y  
{ [HI&>dm=$  
while(nStartPos < nEndPos && !bStop) ?v-IN  
{ 5!$m3j_,]?  
E1IRb':  
>^LVj[.1  
try{ F`S OF O  
URL url = new URL(sURL); .F:qJ6E  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); , mEFp_a+  
httpConnection.setRequestProperty("User-Agent","NetFox"); A`v(hBM  
String sProperty = "bytes="+nStartPos+"-"; -ZFeE[Z  
httpConnection.setRequestProperty("RANGE",sProperty); o90SXa&l/  
Utility.log(sProperty); W.iL!x.B@  
iwWy]V m7  
<MZ$baK  
InputStream input = httpConnection.getInputStream(); ZZOBMF7  
//logResponseHead(httpConnection); 3t22KY[`  
&f'\9lO  
M[$(Pu  
byte[] b = new byte[1024]; #c@Dn.W  
int nRead; "u5Hm ^H  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) n)uvN  
{ p.^mOkpt  
nStartPos += fileAccessI.write(b,0,nRead); 6NH.!}"G9  
//if(nThreadID == 1) LWHP31{R  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); xy>wA  
} x- kCNy  
n"vl%!B  
%^[45e  
Utility.log("Thread " + nThreadID + " is over!"); rGuhYYvK  
bDownOver = true; -Bbg'=QZa  
//nPos = fileAccessI.write (b,0,nRead); O=LS~&=,  
} wH=  
catch(Exception e){e.printStackTrace ();} kCfSF%W&  
} RR!(,j^M  
} *vv <@+gA  
7)$U>|=  
NLFs)6\  
//打印回应的头信息 .o91^jt  
public void logResponseHead(HttpURLConnection con) (rO_ Vfaa  
{ qKt8sxg  
for(int i=1;;i++) '#$Y :/  
{ :,"dno7OQ  
String header=con.getHeaderFieldKey(i); JL $6Fw;  
if(header!=null) rHPda?&H  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); $'e;ScH  
Utility.log(header+" : "+con.getHeaderField(header)); L0uvRge  
else ,{:c<W:A]  
break; w{k8Y?  
} 'c5#M,G~  
} K y~ 9's  
44FK%TmtF  
IF~i*  
public void splitterStop() m76**X  
{ =2uE\6Fl,  
bStop = true; 0/hX3h  
} _d6mf4M]5  
~K%]9  
j[NA3Vj1P  
} W"Hjn/xSS  
LqIMU4Ex  
Ntr5Q IPd  
/* &&$/>[0=.  
**FileAccess.java nL!h hseH  
*//文件访问(定位,写) /]%,C   
package NetFox; 58zs% +F  
import java.io.*; AE!WYE  
S+>&O3m  
MbLG8T:y  
public class FileAccessI implements Serializable{ (Dn-vY'  
<r\)hx0ov  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 %fyb?6?Y  
RandomAccessFile oSavedFile; DQ9s57VxC!  
long nPos; lZua"Ju  
AnyFg)a<  
}(],*^'u-  
public FileAccessI() throws IOException ,AD| u_pP  
{ HaC3y[LJ0  
this("",0); 6d.m@T6~  
} P0Jd6"sS"  
Xo*$|9[.  
FU[,,a0<<  
public FileAccessI(String sName,long nPos) throws IOException q-o>yjT~  
{ 0Fw\iy1o  
oSavedFile = new RandomAccessFile(sName,"rw"); 1Efl|lV  
this.nPos = nPos; ljis3{kn""  
oSavedFile.seek(nPos); n=SZ8Rj7  
} f|G7L5-  
@uE=)mP@  
'|/_='  
public synchronized int write(byte[] b,int nStart,int nLen) &B2c]GoW  
{ T7T!v  
int n = -1; "@?|Vv,vn  
try{ :^s7#4%6  
oSavedFile.write(b,nStart,nLen); M"vcF5q  
n = nLen; u7C{>  
} 8 (KfX%  
catch(IOException e) 0;H6b=  
{ (XwLKkw0n  
e.printStackTrace (); =qtoDe  
} 0V#t ;`Q3  
/T(\}Z  
w.Vynb  
return n; 9v F2aLPk  
} 5Hm!5:ZB  
0xxzhlKNL  
@NNLzqqY  
} cO RMR!  
+.lWck  
D,n}Qf!GYk  
/* U&n>fXTHn  
**SiteInfoBean.java ;F""}wzn  
*/ !~N4}!X3du  
package NetFox; .lBY"W&{  
Vrj1$NL%  
fBgKX ?Y  
public class SiteInfoBean { MH.,s@  
YU=ZZEVi  
qZJ*J+  
private String sSiteURL; //Site's URL w;EXjl;X O  
private String sFilePath; //Saved File's Path 0Mu8ZVI{  
private String sFileName; //Saved File's Name Dw=Z_+J  
private int nSplitter; //Count of Splited Downloading File @5jG  
"x;k'{S  
ewrWSffe  
public SiteInfoBean() 6eT'[Umx  
{//nSplitter的缺省值为5 eqZ+no  
//default value of nSplitter is 5 a9Fm Y`  
this("","","",5); 5g1M_8e'+  
} 3rdfg  
qggk:cN1  
43>9)t  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) |[ Ie.&)  
{ lU $4NU wM  
sSiteURL= sURL; g. ?*F#2  
sFilePath = sPath; /S]:dDY9K  
sFileName = sName; qB F!b0lr  
this.nSplitter = nSpiltter; V3mjb H>F  
S\9t4Ki_'  
I f3{E  
} * -KJh_  
c6,s+^^  
%o@['9U[j  
public String getSSiteURL() 9q1HSJ1)  
{ " ^HK@$  
return sSiteURL; :}@C9pqr2  
} "{A*(.  
rGnI(m.  
_8Nw D_"  
public void setSSiteURL(String value) u C,"5C  
{ Z5G]p4  
sSiteURL = value; YlswSQ  
} AH2 _#\  
*jM_wwG  
EBoGJ_l  
public String getSFilePath() fJN*s  
{ D W/1 =3  
return sFilePath; PiMKu|,3  
} d/D,P=j"  
_wf5%(~b  
{=UFk-$=  
public void setSFilePath(String value) M1oPOC\0.  
{ YD&|1h  
sFilePath = value; /g_9m  
} Y^52~[w~  
eV"!/A2:N5  
e`i7ah;  
public String getSFileName() U1ZIuDg'E  
{ lVPOYl%  
return sFileName; ^SZw`]  
} :e*DTVv8  
wfgqgPo!v  
opsQn\4DZ?  
public void setSFileName(String value) dj'm, k b  
{ NJtQx2Sd'H  
sFileName = value; z{9=1XY  
} w|IjQ1{  
veeI==]  
*G9sy_  
public int getNSplitter() i AdGgK  
{ ~q)u(W C|  
return nSplitter; zuSq+px L@  
} .evbE O5  
K]c4"JJ  
07V8;A<,  
public void setNSplitter(int nCount) hi ~}  
{ x2co>.i  
nSplitter = nCount; hoa7   
} 8WL8/  
} j[I`\"  
98R KCc9h  
X'f.Q  
/* ';0 qj$ #  
**Utility.java #]CFA9 z  
*/ #2RiLht  
package NetFox; +k.%PO0np  
y}FZD?"  
Z:*@5  
public class Utility { $= B8qZ+  
!M7<BD};  
8S]".  
public Utility() \P;rES'  
{ g:7,~}_}^  
0fm*`4Q  
~ Vw9  
} LJFG0 W  
Ml?~ |_  
//线程睡眠 .1yT*+`  
public static void sleep(int nSecond) %c|UmKKi  
{ IvHh4DU3Z  
try{ zce`\ /:  
Thread.sleep(nSecond);  R'}95S<  
} 7j$Pt8$  
catch(Exception e) :O-iykXyI  
{ 7y^%7U \  
e.printStackTrace (); {2&m`D bm  
} ,](:<A)W&  
} K+Y^>N4m  
oVvc?P  
//日志 69m ;XdkKz  
public static void log(String sMsg) 6at1bQ$  
{ 3S*AxAeg  
System.err.println(sMsg); ^qGb%! l  
} ^n1%OzGK#  
0 B@n{PvR0  
z~*g~RKS!  
public static void log(int sMsg) g.py+ ZFJ  
{ = ?D(g  
System.err.println(sMsg); m: n` g1  
} )s_n  
} dCyqvg6u  
=m89z}Ot  
{\H/y c|@  
/* +mj*o(  
**TestMethod.java ^I8Esl8  
*/ Fm\"{)V:b  
package NetFox; %nN `|\  
qgIb/6;xQ  
>Y7a4~ufko  
public class TestMethod { [.se|]t7X  
PZxAH9 S?  
-fhN"B)  
public TestMethod() K<?nq0-  
{ ///xx/weblogic60b2_win.exe <q*oV  
try{ **9x?s  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ^;!0j9"* :  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); j',W 64  
SiteFileFetch fileFetch = new SiteFileFetch(bean); v+p {|X-  
fileFetch.start(); {3;AwhN0H  
} fjvN$NgVs  
catch(Exception e){e.printStackTrace ();} V7#v6!7A@  
EA ]+vq  
Lg8nj< TF  
} Uc/+gz Z;  
8!.ojdyn  
zvABU+{jD  
public static void main(String[] args) DZzN>9<)^  
{ :0Z^uuk`gq  
new TestMethod(); g^*<f8 ~d  
} <: &*  
} r0p w_j  
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