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http断点续传简单实现(java)

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/* K7_)!=DcX  
**SiteFileFetch.java y>~Ke UC  
*/ ;j/ur\37  
package NetFox; .vT'hu  
import java.io.*; (.n" J2qj  
import java.net.*; _$=xa6YA  
wkd591d*  
Fg,[=CqB[  
public class SiteFileFetch extends Thread { 5<#H=A~(  
?W(wtp,o  
wh~~g qi9  
SiteInfoBean siteInfoBean = null; //文件信息Bean m?M(79u[  
long[] nStartPos; //开始位置 |]m&LC  
long[] nEndPos; //结束位置 ( bBetX  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Y<0f1N  
long nFileLength; //文件长度 9r8{9h:  
boolean bFirst = true; //是否第一次取文件 }xdI{E1 q)  
boolean bStop = false; //停止标志 X=.+XP]  
File tmpFile; //文件下载的临时信息 H=yD}!j  
DataOutputStream output; //输出到文件的输出流 G&Cl:CtC  
t*D[Q$v  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) &.4lhfI+(Q  
public SiteFileFetch(SiteInfoBean bean) throws IOException (bT\HW%m  
{ L>@6lhD)x  
siteInfoBean = bean; *#2`b%qh\M  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); h hd n9n  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); |Ec$%  
if(tmpFile.exists ()) :+R ||q i  
{ b1 KiO2 E  
bFirst = false; }wv$ #H[  
read_nPos(); #lB[]2]N  
} _;@kS<\N  
else |r /}r,t}  
{ dmF<J>[  
nStartPos = new long[bean.getNSplitter()]; c/x(v=LW  
nEndPos = new long[bean.getNSplitter()]; $[|8bE  
} "0/OpT7h7  
n1cAI|ZE  
y'zEaL&SI@  
atN`w=6A`  
} Nq9(O#}  
N[42al  
-}N{'S,Bp  
public void run() HV?awc  
{ 1DLQ Zq  
//获得文件长度 H$[--_dI{  
//分割文件 WrD20Q$9Q  
//实例FileSplitterFetch {)%B?75~  
//启动FileSplitterFetch线程 c9'#G>&h~^  
//等待子线程返回 /Fv1Z=:r  
try{ zBoU;d%p>  
if(bFirst) }~ +  
{ JT:9"lmJz,  
nFileLength = getFileSize(); Az)P&*2:'`  
if(nFileLength == -1) ;N/c5+  
{ wvc?2~`  
System.err.println("File Length is not known!"); r^\^*FD |  
} Q5jP`<zWU  
else if(nFileLength == -2) Z]Qm64^I  
{ Y@r#:BH )  
System.err.println("File is not access!"); hrXN 38-  
} '+}hVfN  
else ? `w ~1  
{ rzO:9# d  
for(int i=0;i<nStartPos.length;i++) Gpgi@ Uf  
{ .z{7 rH  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); EG1SIEo  
} g^]Q*EBa  
for(int i=0;i<nEndPos.length-1;i++) UIu'x_qc  
{ {`3;Pd`  
nEndPos = nStartPos[i+1]; De^is^{  
} #~#_) \l'F  
nEndPos[nEndPos.length-1] = nFileLength; nxH$$}9  
} r^ "mPgY  
} yDyq. -Q  
t^7R6y  
y k#:.5H  
//启动子线程 @E==~ b  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ~ib#x~Db  
for(int i=0;i<nStartPos.length;i++) @L~y%#  
{ '17=1\Ss6;  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ~pF'Qw" z|  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), o+tY[UX  
nStartPos,nEndPos,i); &bL1G(}  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); V)0bLR  
fileSplitterFetch.start(); HSUr  
} qGh rJ6R!  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 2R5]UR S  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); v)pdm\P  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ae^xuM?7  
nEndPos = " + nFileLength); c{852R  
// fileSplitterFetch[nPos.length-1].start(); Y8AU<M  
%V+,#  
Us%VB q  
//等待子线程结束 -(59F  
//int count = 0; j"NqNv  
//是否结束while循环 fx}R7GN2  
boolean breakWhile = false; =_wgKXBFa  
ioviJ7N% O  
A2vOI8  
while(!bStop) d>aZpJ[.  
{ v\HGL56T  
write_nPos(); a1}W2;W0]g  
Utility.sleep(500); Z>D7C?v:(  
breakWhile = true; bh_ALu^CSX  
.Ftml'!  
A] F K\  
for(int i=0;i<nStartPos.length;i++) 2dq{n.cgs  
{ LEhi/>T  
if(!fileSplitterFetch.bDownOver) (Q'XjN\#  
{ ;wN.RPE_^  
breakWhile = false; R]r~TJ o  
break; }U(^QB  
} ]>AW  
} r`&ofk1K  
if(breakWhile) "7aFVf  
break; 9u)h$VC  
Og&2,`Jb  
$]T7Iwk  
//count++; F1+2V"~  
//if(count>4) bk7miRIB  
// siteStop(); U .rH,`  
} bX9}G#+U  
KcrF=cA  
o/[NUQSI  
System.err.println("文件下载结束!"); *U]f6Q<X  
} ' Wi*[  
catch(Exception e){e.printStackTrace ();} xp39TiXJ*  
} 0qTa @y  
3oIoQj+D  
B02~/9*Y"  
//获得文件长度 "90}H0(+  
public long getFileSize() :N[2*.c[  
{ .O,gl$y}  
int nFileLength = -1; hrW.TwK  
try{ 0}b8S48|?  
URL url = new URL(siteInfoBean.getSSiteURL()); V}J W@  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); T|}HK]QOX  
httpConnection.setRequestProperty("User-Agent","NetFox"); .6tz ^4  
/!E /9[V  
Uvuvr_IP  
int responseCode=httpConnection.getResponseCode(); S\f^y8*<  
if(responseCode>=400) 7<KRB\)b&  
{ -kJF@w6u  
processErrorCode(responseCode); FIS-xpv$  
return -2; //-2 represent access is error ~pw_*AN  
} d_yqmx?w  
bcZHFX  
` Y ut 1N  
String sHeader; p"X\]g^jA>  
VJNPs6  
L,l+1`Jz  
for(int i=1;;i++) Gm|QOuw  
{ Jsw<,uT D  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); A1Zu^_y'  
//Utility.log(in.readLine()); ZWr\v!4  
sHeader=httpConnection.getHeaderFieldKey(i); \"lzmxe0p  
if(sHeader!=null) Z c"]Cv(  
{ 7_{x '#7  
if(sHeader.equals("Content-Length")) +FJ o!~1  
{ a;lCr|*  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); `=\G>#p<T  
break; ;j(xrPNb  
} cis ~]x%  
} 0 @ ,@  
else  10DS  
break; %d=-<EQ|&  
} `P GWu1/  
} s_kI\w4(x1  
catch(IOException e){e.printStackTrace ();} M'g4alS  
catch(Exception e){e.printStackTrace ();}  (0k0gq;  
bc 0|tJc  
P@Qo2zTh%  
Utility.log(nFileLength); F-ZD6l9O  
.f6_[cS;g  
SGbo|Xe7:  
return nFileLength; 6\]-J*e>  
} Pjx9@i  
Gis'IX(  
;ndg,05_  
//保存下载信息(文件指针位置) 6?t5g4q*nn  
private void write_nPos() GY4yZa  
{ e;gf??8}  
try{ P(Lwpa,S  
output = new DataOutputStream(new FileOutputStream(tmpFile)); BY 1~\M  
output.writeInt(nStartPos.length); S#""((U$  
for(int i=0;i<nStartPos.length;i++) CsE|pXVG  
{ hMDyE.X-  
// output.writeLong(nPos); D_8hn3FH  
output.writeLong(fileSplitterFetch.nStartPos); Jv7M[SJ#x  
output.writeLong(fileSplitterFetch.nEndPos); 9 np<r82  
} W]R5\ G*  
output.close(); gG $o8c-  
} R vY`9D  
catch(IOException e){e.printStackTrace ();} /wK7l-S  
catch(Exception e){e.printStackTrace ();} hqE#BnQxP,  
} +wio:==  
?Z.YJXoKZ  
JlH|=nIaj6  
//读取保存的下载信息(文件指针位置) } K Ou  
private void read_nPos() WTd}) s  
{ A8A+ImwO"  
try{ uIba{9tM"P  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); RJ-CWt [LG  
int nCount = input.readInt(); w}E?FEe.  
nStartPos = new long[nCount]; 1]kk  
nEndPos = new long[nCount]; vi=yR  
for(int i=0;i<nStartPos.length;i++) 1k hwwoo  
{ _\1(7?0D  
nStartPos = input.readLong(); +6>Pp[%  
nEndPos = input.readLong(); 1E-$f  
} `SU;TN0  
input.close(); AHLDURv  
} !YoKKG~_0  
catch(IOException e){e.printStackTrace ();} 7eq;dNB@gq  
catch(Exception e){e.printStackTrace ();} . XY'l  
} $)uQ%/DH>  
C= Zuy^  
Nd0Wt4=  
private void processErrorCode(int nErrorCode) weDv[b5i  
{ }\irr9,  
System.err.println("Error Code : " + nErrorCode); 5<S1,u5  
} 6jnRC*!?  
(z.Vwl5  
G9gvOEI/  
//停止文件下载 \2LCpN  
public void siteStop() c.XLEjV|  
{ @e slF  
bStop = true; I4)vJ0  
for(int i=0;i<nStartPos.length;i++) ]~oM'?&!  
fileSplitterFetch.splitterStop(); Rp|:$5&nE  
"C.$qk]  
?@u &3/&  
} !]`]67lC  
} Zdak))7  
//负责部分文件的抓取 d#W[<,  
**FileSplitterFetch.java D~ {)\;w^!  
*/ %:/;R_  
package NetFox; !l&lb]V cz  
&fTCY-W[  
l%)XPb2$J  
import java.io.*; FX'W%_f,  
import java.net.*; ~C[,P\,  
m1cyCD  
nQgn^z#  
public class FileSplitterFetch extends Thread { D +oo5  
v:+se6HY?p  
6$z UFIk  
String sURL; //File URL <&NR3^Eq  
long nStartPos; //File Snippet Start Position S !e0 :  
long nEndPos; //File Snippet End Position ql zL<  
int nThreadID; //Thread's ID K[9<a>D`  
boolean bDownOver = false; //Downing is over  {<i!Pm  
boolean bStop = false; //Stop identical }Jc^p  
FileAccessI fileAccessI = null; //File Access interface *7Mrng  
II2oV}7?  
;S%wPXj&  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ;uJVY)7a  
{ \GkcK$Y  
this.sURL = sURL; 6ZM<M7(V  
this.nStartPos = nStart; @3G3l|~>  
this.nEndPos = nEnd; K>q,?x b  
nThreadID = id; ~!uK;hI  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 fpqKa r  
} 6m{3GKaW~  
63~i6  
\ pq]q  
public void run() \gzNMI*  
{ g_q{3PW.  
while(nStartPos < nEndPos && !bStop) eD/?$@y  
{ EEaFi 8  
|GsLcUv6  
}{ P}P}  
try{ Rw7Q[I5z%  
URL url = new URL(sURL); +uH1rF_&@  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); H<>x_}&  
httpConnection.setRequestProperty("User-Agent","NetFox"); ZE1#{u~[y  
String sProperty = "bytes="+nStartPos+"-"; 2{%BQq>C  
httpConnection.setRequestProperty("RANGE",sProperty); W[vak F  
Utility.log(sProperty); ~vt8|OOo0  
f&,.h"bS  
[m4<j  
InputStream input = httpConnection.getInputStream(); ':fVb3A[*d  
//logResponseHead(httpConnection); 4f>Vg$4  
qzH97<M}T  
> vahj,CZZ  
byte[] b = new byte[1024]; 'E@D  
int nRead; AvwX 2?tc  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) eC3ZK"oJ  
{ }b{N[  
nStartPos += fileAccessI.write(b,0,nRead); 1\3n   
//if(nThreadID == 1) 1,/oS&?E  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); )i?wBxq'MA  
} #A|M NJ%m  
5zU D W?  
w ggl,+7  
Utility.log("Thread " + nThreadID + " is over!"); 'Kq%t M26!  
bDownOver = true; &^Xm4r%u_  
//nPos = fileAccessI.write (b,0,nRead); 4}0s^>R  
} a]Lr<i8#%  
catch(Exception e){e.printStackTrace ();} YlYTH_L>E  
} )cvC9gt  
} +Oxl1fDf  
P3:hGmk8|j  
*v&g>Ni  
//打印回应的头信息 Z)ObFJMG5  
public void logResponseHead(HttpURLConnection con) N#UyAm<9  
{ D,R/abYZH  
for(int i=1;;i++) ){,8}(|  
{ 0>AA-~=-  
String header=con.getHeaderFieldKey(i); ed617J  
if(header!=null) e06r5%|.%  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); VJPt/Dy{  
Utility.log(header+" : "+con.getHeaderField(header)); Vdjca:`  
else f6z[k_lLN  
break; sqkPC_;A  
} jfI|( P  
} toP7b  
zIlQqyOQ8  
m7d? SU  
public void splitterStop() (l$bA_F \  
{ X09& S4  
bStop = true; x&7!m  
}  ]@<O!fS  
1_F2{n:yp  
x&kF;UC  
} Wx^L~[l  
BK-{z).)  
C^ uXJ~8  
/* pE`BB{[@  
**FileAccess.java `M|fwlAJQ  
*//文件访问(定位,写) R@ihN?k  
package NetFox; mH;\z;lyK  
import java.io.*; `i<U;?=0'  
<Nkj)`%5iK  
-`A6K!W&~p  
public class FileAccessI implements Serializable{ %SIbpk%  
_TkiI.'  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ZX'/[wAN)  
RandomAccessFile oSavedFile; 1YQ|KJ*K  
long nPos; >8QLo8)3C  
t.3b\RV[  
k|&@xEbS  
public FileAccessI() throws IOException MvQ0"-ZQ  
{ tLLP2^_&  
this("",0); pWeKN`  
} l].dOso$`  
O,hT< s "  
VBy=X\w]  
public FileAccessI(String sName,long nPos) throws IOException V:yia^1  
{ rry 33  
oSavedFile = new RandomAccessFile(sName,"rw"); `2}Mz9mk  
this.nPos = nPos; Z}WMpp^r  
oSavedFile.seek(nPos); l+RBe<Mq  
} (rvK@  
+1_NB;,e  
"*<9)vQ6|  
public synchronized int write(byte[] b,int nStart,int nLen) s<aJ pi{n4  
{ j^>J*gLM}W  
int n = -1; XB^o>/|@S  
try{ ;QS-a  
oSavedFile.write(b,nStart,nLen); 4y:yFTp  
n = nLen; l(*`,-pv:  
} gP? pfFhG  
catch(IOException e) N<9C V!_  
{ R9^Vk*`gFU  
e.printStackTrace (); RYy_Ppn96f  
} +A O(e  
A-qdTJP  
pm@Mlwg`1  
return n; KP%A0   
} ~CQsv `  
/n&w|b%  
G D$o |l]\  
} up#W"`"  
4uwI=UUB  
Jzo|$W  
/* >2tYw,m  
**SiteInfoBean.java !T!U@e=u  
*/ xhWWl(r`5  
package NetFox; u%}zLwMH  
JN,4#,  
^cn%]X#.  
public class SiteInfoBean { Il`35~a  
=# <!s!  
JgEPzHgx  
private String sSiteURL; //Site's URL Se{}OG)  
private String sFilePath; //Saved File's Path /0A9d-Qd<  
private String sFileName; //Saved File's Name ]MKW5Kq  
private int nSplitter; //Count of Splited Downloading File XShi[7  
-c{O!z6sX  
p D-k<8|  
public SiteInfoBean() \QGh@AQp"  
{//nSplitter的缺省值为5 Op0n.\>  
//default value of nSplitter is 5 p(=}Qqdr8  
this("","","",5); Cjc>0)f&.  
} +`}QIp0  
ibAZ=RD  
*eK\W00  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) &e0BL z  
{ m&a.i B  
sSiteURL= sURL; W US[hx,  
sFilePath = sPath; H|JPqBNRh  
sFileName = sName; TF R8  
this.nSplitter = nSpiltter; G)t_;iNL|  
o<cg9  
1DLAfsLlj  
} 6V-u<FJ  
mSdByT+dG  
:#7"SEud}  
public String getSSiteURL() 6?i]oy^X]p  
{ <n? cRk'.  
return sSiteURL; 42]hX9E  
} T+1:[bqK  
G9v'a&  
:{BD/6  
public void setSSiteURL(String value) `1 A,sXfa  
{ >}? jOB  
sSiteURL = value; A{NKHn>%`  
} 4&N#d;ErC  
Pw+PBIGn4  
JbX"K< nQ  
public String getSFilePath() oN({X/P2j  
{ sE:~+C6o:  
return sFilePath; H{ M7_1T  
} G5A:C(r  
EdcbWf7  
QiKci%=SX  
public void setSFilePath(String value) J'}G~rB<<  
{ ~?#>QN\\c  
sFilePath = value; *uW l 804  
} 7qsu0 .[d  
e%[0 NVo  
!$n@-  
public String getSFileName() hQ7-m.UZw  
{ 4*Uzomb?q  
return sFileName; fab. %$  
} w}|XSJ!  
HKp|I%b]J  
UlP2VKM1&  
public void setSFileName(String value) S3oyx#R('O  
{ aQ.QkM Z  
sFileName = value; G.")Bg  
} |#(KP  
 A:b(@'h  
w :nYsuF  
public int getNSplitter() 5}C.^J`  
{ 'Dn\.x^]1  
return nSplitter; [J!jp& o  
} ~F"<Nq  
a_Sp}s<J  
b!p]\B!  
public void setNSplitter(int nCount) NMs 8^O|0  
{ r{cmw`WA/P  
nSplitter = nCount; DplS\}='s  
} [x%[N)U3  
} I4XnJ[N%  
\qf0=CPw8  
kz_gR;"(Z  
/* z( \4{Y  
**Utility.java M}fk[Yr>  
*/ $-=xG&fSz  
package NetFox; B%7Az!GX  
/ f5q9sp8  
22OfbwCb  
public class Utility { 9epMw-)k  
cs lZ;  
y#T.w0*  
public Utility() r1 axC%  
{ ^r=Wj@`  
s5/u>d  
NiH =T  
} ~] &yHzp2  
`- HI)-A97  
//线程睡眠 TTa$wiW7'  
public static void sleep(int nSecond) 8TBv~Q u  
{ FMOO  
try{ $-)T  
Thread.sleep(nSecond); @ D,]v:  
} f@@7?5fW  
catch(Exception e) l"zA~W/  
{ ;~-ZN?8   
e.printStackTrace (); TMsc5E  
} jj&mRF0gCb  
} I A%ZCdA;  
3q W](  
//日志 B[ .$<$}G  
public static void log(String sMsg) skm~~JM^  
{ 38 ] }+Bb  
System.err.println(sMsg); ;Rlf[](iL  
} Z;O!KsJ  
t[r 6jo7  
Sa[?B  
public static void log(int sMsg) =X1oB ,W{  
{ !,+<?o y  
System.err.println(sMsg); `w&?SXFO8  
} z:a7)z  
} ]]o?!NX  
Kf-XL ),3l  
o|$r;<o3R  
/* RNF%i~nhO  
**TestMethod.java &S=Qu?H  
*/ 2`^6``  
package NetFox; gR+P !Eow  
Mkh/+f4  
[_eT{v2B4  
public class TestMethod { ppo.#p0w  
{,!!jeOO  
- {}(U  
public TestMethod() ]=o1to-  
{ ///xx/weblogic60b2_win.exe L +mE&  
try{ 6FYL},.R  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); &OlX CxH  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); =xQPg0g  
SiteFileFetch fileFetch = new SiteFileFetch(bean); v%r/PHw  
fileFetch.start(); O>N/6Z  
} {)iiu  
catch(Exception e){e.printStackTrace ();} 3:O|p[2)L  
 aGOS 9  
PR/>E60H  
} '>ASr]Q  
%+ nM4)h  
M]|]b-#  
public static void main(String[] args) Y<IuwS  
{ Ee_?aG e&  
new TestMethod(); /6rQ.+|).  
} h<V,0sZ&:  
} o|u4C{j  
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