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http断点续传简单实现(java)

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/* R\B-cU[,  
**SiteFileFetch.java 3k J8Wn  
*/ dDAI fe2y  
package NetFox; VQQtxHTC3  
import java.io.*; $]Vvu{  
import java.net.*; dBKceL v  
;%j1'VI  
^\z.E?v%  
public class SiteFileFetch extends Thread { <{"]&bl  
El}."}l&  
,(6U3W*bu  
SiteInfoBean siteInfoBean = null; //文件信息Bean l<]@5"wN  
long[] nStartPos; //开始位置 9,4Lb]  
long[] nEndPos; //结束位置 JIl<4 %A  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 *hP9d;-Ar  
long nFileLength; //文件长度 %$)[qa3  
boolean bFirst = true; //是否第一次取文件 c<`Z[EY(t  
boolean bStop = false; //停止标志 -Tw96 dv  
File tmpFile; //文件下载的临时信息 #Tjv(O[&  
DataOutputStream output; //输出到文件的输出流 -xc*R%k  
B|~tW21  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) ;!JI$_ -\  
public SiteFileFetch(SiteInfoBean bean) throws IOException S-^RZ"  
{ i9qn_/<c  
siteInfoBean = bean; =-r[ s%t &  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); yH'vhtop  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 8e`'Ox_5a  
if(tmpFile.exists ()) 2&f] v`|M|  
{ GtCbzNY  
bFirst = false; ]5+db0  
read_nPos(); c3X'Sv  
} L@"1d.k_  
else 0<8p G:BQ  
{ ZZ<uiN$  
nStartPos = new long[bean.getNSplitter()]; 5w\>Whbd  
nEndPos = new long[bean.getNSplitter()]; ;<JyA3i^V,  
} [84f[`!Ui  
1@j0kTJ~m  
"QWF&-kAI  
=,/08Cs  
} :3z`+5Y*  
~JJuM  
~i4h.ZLj  
public void run() _k0 X)N+li  
{ q"|,HpQ  
//获得文件长度 t4a/\{/#9|  
//分割文件 #+v Iq?  
//实例FileSplitterFetch oA^aT:o +  
//启动FileSplitterFetch线程 SIBNU3;DL  
//等待子线程返回 `kn 'RZR  
try{ oJcDs-!  
if(bFirst) (~R[K,G  
{ s)=fs#%  
nFileLength = getFileSize(); x:h0/f  
if(nFileLength == -1) D5wy7`c  
{ [7Yfv Xp  
System.err.println("File Length is not known!"); ;^9Ao>(?y  
} CnJrJ>l  
else if(nFileLength == -2) t8Sblgq  
{ DriJn`vtzq  
System.err.println("File is not access!"); mG? g  
} s&<6{AU(id  
else 3HU_ ~%l  
{ \ 2$nFr?0  
for(int i=0;i<nStartPos.length;i++) +bG^SH2ke  
{ nhfHY-l} 7  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); %Ts6M,Fpp  
} QEe\1>1"&  
for(int i=0;i<nEndPos.length-1;i++) 6;02_C]\o  
{ $*035f  
nEndPos = nStartPos[i+1]; `CW I%V  
} Ue>;h9^  
nEndPos[nEndPos.length-1] = nFileLength; ~nQv yM!$  
} t:DZow  
} +:hZ,G?>  
{bxTODt@  
}klET   
//启动子线程 =l  %  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; As$:V<Z  
for(int i=0;i<nStartPos.length;i++) 0w0\TWz*   
{ i'GBj,:  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), q~[@(+zP5  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),  p)5j~Nl  
nStartPos,nEndPos,i); W| z djb  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 1Na*7|  
fileSplitterFetch.start(); i8F^ N=  
} kZ&|.q1zki  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Z /#&c  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); v"y0D  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 82S?@%}#J  
nEndPos = " + nFileLength); FT*OF 3  
// fileSplitterFetch[nPos.length-1].start(); ,_STt)  
{XT3M{`rWL  
^sLnKAN  
//等待子线程结束 :L~{Q>o  
//int count = 0; Q\pTyNAYn  
//是否结束while循环 =Kq/E De  
boolean breakWhile = false; }ze,6T*z  
cQ= "3M)~r  
6}Se$XMl  
while(!bStop) <Yzk]98W5.  
{ ,G";ny[$  
write_nPos(); \7W4)>At-  
Utility.sleep(500); {u3eel  
breakWhile = true; lzJ[`i.  
8VbHZ9Q  
AS 5\X.%L*  
for(int i=0;i<nStartPos.length;i++) X2X.&^  
{ 5H (CP  
if(!fileSplitterFetch.bDownOver) zh5$$*\  
{ J^}w,r *=  
breakWhile = false; |'w_5?|4  
break; K4]42#  
} 8<,b5  
} PNm WZW*  
if(breakWhile) wA@y B"  
break; c4]/{!4 Q  
$$U Mc-Pq  
q|*}>=NX  
//count++; jwm2ZJW  
//if(count>4) h/I'9&J>*  
// siteStop(); I! s&m%s  
} ^tWt"GgC  
-8sm^A>C  
u/`jb2eEU:  
System.err.println("文件下载结束!"); yc./:t1at>  
}  3kAmRU  
catch(Exception e){e.printStackTrace ();} ?^F*M#%?  
} m!{}Y]FZn  
I)wjTTM5  
c\X0*GX  
//获得文件长度 'dE G\?v9  
public long getFileSize() q+A^JjzT  
{ ?vHow$  
int nFileLength = -1; BUH~aV  
try{ KmuE#Ia  
URL url = new URL(siteInfoBean.getSSiteURL()); ~Wh} W((L  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); G~,K$z/-l  
httpConnection.setRequestProperty("User-Agent","NetFox"); (~YFm"S  
=5NM =K  
R|7yhsJq,  
int responseCode=httpConnection.getResponseCode(); ( K5w0  
if(responseCode>=400) I\NiA>c  
{ v&BKl  
processErrorCode(responseCode); ye-o'%{  
return -2; //-2 represent access is error 0_Gi1)  
} jy=dB-&  
rgQ6/3}qc  
'b#`)w@/=  
String sHeader; 6`sOhVD  
Y2&>;ym!  
)&G uZ  
for(int i=1;;i++) bFivHms  
{ x/nlIoT  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); f1c Q*#2~  
//Utility.log(in.readLine()); %s.hqr,I  
sHeader=httpConnection.getHeaderFieldKey(i); g+5{&YD  
if(sHeader!=null) zzf;3S?  
{ Y{].%xM5  
if(sHeader.equals("Content-Length")) {`Ekv/XWa  
{ em^|E73  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); pdcP;.   
break; ]Y#$!fIx  
} Ri$wt.b  
} `;[ j`v8O  
else JCjQR`)  
break; uZsm=('ww  
} UlBg6   
} 8&15k A  
catch(IOException e){e.printStackTrace ();} . &dh7` l  
catch(Exception e){e.printStackTrace ();} C4Pi6.wf  
# 2As-9  
vn n4  
Utility.log(nFileLength); _xgF?#  
;^5d^-T  
.&:GO D  
return nFileLength; GA19=gow  
} +xqPyR  
hFORs.L&G  
OiB*,TWV  
//保存下载信息(文件指针位置)  &!I^m  
private void write_nPos() 7U#`^Q}  
{ f_`gUMf  
try{ )9~1XiS,  
output = new DataOutputStream(new FileOutputStream(tmpFile)); OrX x0Hn  
output.writeInt(nStartPos.length); 7%p[n;-o&  
for(int i=0;i<nStartPos.length;i++) i ! wzID  
{ =^. f)  
// output.writeLong(nPos); nSH A,c  
output.writeLong(fileSplitterFetch.nStartPos); [al,UO  
output.writeLong(fileSplitterFetch.nEndPos); #"}Z'|X*  
} s : c  
output.close(); yZf+*j/a7  
} (<ybst6+I  
catch(IOException e){e.printStackTrace ();} ?b',kN,(  
catch(Exception e){e.printStackTrace ();} az7<@vSXi  
} O.7Q* ^_  
neQ2k=ao  
1jdv<\U   
//读取保存的下载信息(文件指针位置) qaBjV6loy  
private void read_nPos() Wsb=SM7;  
{ 5oz[Njq4  
try{ ()=u#y  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 0sjw`<ic  
int nCount = input.readInt(); zV)Ob0M7U  
nStartPos = new long[nCount]; }s;W{Q  
nEndPos = new long[nCount]; ># FO0R  
for(int i=0;i<nStartPos.length;i++) Lp\89tB>  
{ &]VCZQL  
nStartPos = input.readLong(); vkE[Ur>  
nEndPos = input.readLong(); 3zJbb3e  
} ZN)a}\]  
input.close(); r>+Hwj0>  
} O=os ,'"  
catch(IOException e){e.printStackTrace ();} kc&>l (  
catch(Exception e){e.printStackTrace ();} RulZh2C  
} F{*S}&q*)o  
'L#qR)t  
du2q6"  
private void processErrorCode(int nErrorCode) @;>TmLs  
{ uVoM2n?D%^  
System.err.println("Error Code : " + nErrorCode); 5MJ`B: He+  
} :0BaEqX  
846j<fE  
pm<zw-  
//停止文件下载 Wx}+Vq<q  
public void siteStop() *#j+,q!X  
{ ~8'4/wh+8  
bStop = true; ,RFcR[ak  
for(int i=0;i<nStartPos.length;i++) lhm=(7Y  
fileSplitterFetch.splitterStop(); wI +oG  
c1j)  
=re1xR!E5  
} YH`/;H=$G/  
} Gy36{*  
//负责部分文件的抓取 CFJ F}aW  
**FileSplitterFetch.java zn5  
*/ \XR%pC  
package NetFox; KK-9[S-  
Dx/!^L02  
pyK|zvr-r  
import java.io.*; ua(y! Im  
import java.net.*; A:3bL: ;t  
VNx|nP&  
'>(R'g42n  
public class FileSplitterFetch extends Thread { Mf0g)X}1  
T:Dp+m!\{  
'tK5s>gv<  
String sURL; //File URL se](hu~w  
long nStartPos; //File Snippet Start Position ;czMsHu0X  
long nEndPos; //File Snippet End Position pfW0)V1t  
int nThreadID; //Thread's ID 1 O+4A[cr  
boolean bDownOver = false; //Downing is over =Haqr*PDx  
boolean bStop = false; //Stop identical 3=xb%Upw  
FileAccessI fileAccessI = null; //File Access interface bu"R2~sb  
TRG(W^<F  
W(9fCDO;  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ToIvyeFr  
{ .fxI)  
this.sURL = sURL; CQfrAk4mu  
this.nStartPos = nStart; -ecP@,  
this.nEndPos = nEnd; 6L~@jg~0A[  
nThreadID = id; _+ K[1P  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 *a Y`[,4#$  
} UJkg|eu  
#3maT*JY  
)AOD~T4s7  
public void run() !Y_"q^5GG'  
{ TDg#O!DUF  
while(nStartPos < nEndPos && !bStop) R}4o{l6  
{ 42LlR 0  
}x4,a6^  
-}k'a{sj=  
try{ lpkg( J#&  
URL url = new URL(sURL); 0j%@P[zQ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ZjLzS]\a  
httpConnection.setRequestProperty("User-Agent","NetFox"); LH.. 8nfl  
String sProperty = "bytes="+nStartPos+"-"; e47JLW&b  
httpConnection.setRequestProperty("RANGE",sProperty); >jAr9Blz]  
Utility.log(sProperty); QZk:G+ $  
+v%V1lf^~  
Ky`rf}cI>  
InputStream input = httpConnection.getInputStream(); +=%13cA*U  
//logResponseHead(httpConnection); }AG$E}~/  
ZjY_AbD  
=flgKRKk.r  
byte[] b = new byte[1024]; ~,yHE3B\G  
int nRead; B+|E|8"  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) p8y_uN QE  
{ 1QM*oj:  
nStartPos += fileAccessI.write(b,0,nRead); J=>?D@K  
//if(nThreadID == 1) J=6 7As  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); /B"h #v-o  
} 94r8DkI  
.EVy?-   
k%#`{#n i  
Utility.log("Thread " + nThreadID + " is over!"); O!='U!X@P  
bDownOver = true; xbrxh-gV  
//nPos = fileAccessI.write (b,0,nRead); BR\% aU$u  
} +NPk9jn  
catch(Exception e){e.printStackTrace ();} 35Nwx<  
} (+>~6SE  
} sd\>|N?'  
W<TW6_*e  
+4ax~fuU  
//打印回应的头信息 V ?3>hQtB  
public void logResponseHead(HttpURLConnection con) a_I!2w<I  
{ a8aEZ724  
for(int i=1;;i++) qVC_K/w 7  
{ &V1N a1`  
String header=con.getHeaderFieldKey(i); S{j|("W"[  
if(header!=null) H V<|eL #  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); a>`\^>G4  
Utility.log(header+" : "+con.getHeaderField(header)); [8.ufpZ  
else "|`8mNC  
break; K|];fd U  
} +Tc4+q!  
} "5e~19  
Z$0r+phQk=  
?*E Y~'I  
public void splitterStop() 7P9n. [  
{ 1Nw&Z0MI  
bStop = true; I"@X~Y7}  
} bv0B  
-@i)2J_WP  
N+l~r]: &  
} 0.O pgv2K  
AL! ^1hCF  
y4) M,+O5  
/* />q=qkdq0  
**FileAccess.java :w(J=0Lt  
*//文件访问(定位,写) /dhx+K~  
package NetFox; Pca~V>Hd  
import java.io.*; ;6t>!2I>C  
;_K+b,  
$-"AMZ899  
public class FileAccessI implements Serializable{ :ORCsl6-  
sF]v$ kq  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 i9k7rEW^  
RandomAccessFile oSavedFile; y#HD1SZ  
long nPos; %0INtq  
0m)["g4  
<1&kCfE&  
public FileAccessI() throws IOException ~X5yHf3  
{ 28SlFu?  
this("",0); F/ 2@%,2n  
} F}0QocD  
1O45M/5\o  
2*n2!7jZ*  
public FileAccessI(String sName,long nPos) throws IOException - t4"BD  
{ :q~qRRmjBe  
oSavedFile = new RandomAccessFile(sName,"rw"); KpC)A5u6  
this.nPos = nPos; \^;Gv%E  
oSavedFile.seek(nPos); w>; :mf  
} +@]1!|@(  
'LFHZ&-  
m0]LY-t  
public synchronized int write(byte[] b,int nStart,int nLen) FFbMG:>:  
{ < .$<d  
int n = -1; dJ?VN!B0  
try{ Y+iC/pd  
oSavedFile.write(b,nStart,nLen); :tdx:  
n = nLen; cZ|D!1%  
} J=*y>Zt-b  
catch(IOException e) 3{Ze>yFE  
{ OnH>g"  
e.printStackTrace (); p1v:X?  
} 0-0 )E&2  
#"ayq,GC<  
KU-z;}9s  
return n; A/{pG#if]3  
} IG`~^-}7lR  
N ED`GU  
Cd'P  
} ce2d)FG}e  
s7I*=}{g0.  
, p1 (0i  
/* & /-@R|  
**SiteInfoBean.java Qat%<;P2  
*/ FvG9PPd  
package NetFox; "x9xJ  
z:u`W#Rf  
$2]1 3j  
public class SiteInfoBean { MGc=TQ.  
@EfCNOy  
Rt7}e09HV  
private String sSiteURL; //Site's URL *Vfas|3hZI  
private String sFilePath; //Saved File's Path z$ysp!  
private String sFileName; //Saved File's Name KyXgw  
private int nSplitter; //Count of Splited Downloading File :m8ED[9b  
KrMIJA4>  
dwrc"GK!o  
public SiteInfoBean() .~v~~VL1NS  
{//nSplitter的缺省值为5 T 6QnCmB4  
//default value of nSplitter is 5 >]:R{1h  
this("","","",5); qqw6p j  
} /T#<g:   
x)"=*Jj  
6i.'S5.  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 6 $ IXER  
{ t vk^L3=<  
sSiteURL= sURL; JsnavI6  
sFilePath = sPath; bIp;$ZHy`K  
sFileName = sName; ^+`vh0TPQ  
this.nSplitter = nSpiltter; t)cG_+rJ  
G]P4[#5  
c::x.B"w  
} Lom%eoH)  
32~Tf,  
e"r}I!.  
public String getSSiteURL() eoEb\zJ  
{ ujz %0Mq;  
return sSiteURL; + W@r p#  
} Z6D4VZVF  
<g*rTqT'  
M|n)LyL  
public void setSSiteURL(String value) %M}zi'qQ?  
{ 7IK<9i4O  
sSiteURL = value; dZ%b|CUb  
} q{U -kuui  
te6[^_k  
~;+i[Z&e  
public String getSFilePath() .Z_U]_(  
{ GbP!l;a  
return sFilePath; l06 q1M 3  
} ` t6lnO  
Efp=z=E  
1/cb;:h>  
public void setSFilePath(String value) Q~xR'G[N  
{ 1'aS2vB9  
sFilePath = value; xR_]^Get  
} .z[+sy_  
g!~j Wn?A  
gKYn*  
public String getSFileName() T{)!>)  
{ "*7I~.7U(*  
return sFileName; e\yj>tQJg  
} 2$\f !6p  
s|,]Nb=z/  
ZM|>Va/X  
public void setSFileName(String value) b%oma{I=.c  
{ G x,D'H'  
sFileName = value; 1c}'o*K_%  
} +Og O<P  
20fCWVw}?}  
fLD9RZ8_  
public int getNSplitter() M  j5C0P(  
{ s &.Z;X  
return nSplitter; R=e`QMq  
} Q'8v!/"}p{  
?-i|f_`  
kkJg/:g  
public void setNSplitter(int nCount) jV<LmVcZY  
{ rW`F|F%  
nSplitter = nCount; UoLO#C0i  
} \6lXsu;I.X  
} x _2]G'  
7Ru0>4B  
,7QnZ=F  
/* ]-}a{z  
**Utility.java v,M2|x\r}  
*/ t[Q^Xp  
package NetFox; "q(&<+D@  
;m5M: Z"  
{'b8;x8h  
public class Utility { WEsH@ [  
|hdh4P$+|  
yq<YGNy!  
public Utility() QqwX Fk  
{ !3b%Q</M H  
Wt`D  
Ja (/ym^  
} ScTqnY$v  
'sA&Pm  
//线程睡眠 z N t7DK  
public static void sleep(int nSecond) /tUl(Fp J`  
{ 4/h2_  
try{ ]Yj>~k:K  
Thread.sleep(nSecond); Gg!))I+  
} jNyC%$  
catch(Exception e) y&CUT:M6  
{ 9.@(&  
e.printStackTrace (); fC-^[Af)  
} jqLyX  
} RhJ<<T.2  
D3K`b4YV  
//日志 6 %=BYDF  
public static void log(String sMsg) {10ms_s  
{ tS9m8(Hr%Q  
System.err.println(sMsg); 1y@-  
} 7d<v\=J}  
z=fag'fzM  
1]<!Xuk^f  
public static void log(int sMsg) 9F-k:hD |  
{ W+eN%w5  
System.err.println(sMsg); ;+jp,( 7  
} oF>GWst TR  
} E??%)q  
e"2QV vB  
FjydEV  
/* zm"\D vN)  
**TestMethod.java J{Ay(  
*/ Cn55%:  
package NetFox; \%C[l  
yjr@v!o  
m3WV<Cbz  
public class TestMethod { {L=[1  
P~ykC{nD  
};j&)M  
public TestMethod() aE%VH ;?  
{ ///xx/weblogic60b2_win.exe H|Nw)*.  
try{ "5YdmBy  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); LBE".+  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); k|_2aQ02  
SiteFileFetch fileFetch = new SiteFileFetch(bean); "4`%NA  
fileFetch.start(); |. 6@-h~8  
} f@{C3E dd  
catch(Exception e){e.printStackTrace ();} IF:M_   
saT9%?4-  
%C)JmaQ{9  
} yRznP)  
[s/@z*,M1  
cDx^}N!  
public static void main(String[] args) Wk|z\OR(  
{ Chua>p!$g  
new TestMethod(); ./ :86@O  
} k$c j|-<  
} gctaarB&  
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