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http断点续传简单实现(java)

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/* a6WE,4T9  
**SiteFileFetch.java "4g1I<  
*/ ":]O3 D{r  
package NetFox; rorzxp{  
import java.io.*; HH^{,53%  
import java.net.*; \Zoo9Wy  
!"2 OcDFx  
\nkqp   
public class SiteFileFetch extends Thread { Km+29  
2:p2u1Q O  
6J%SkuxR  
SiteInfoBean siteInfoBean = null; //文件信息Bean XF^c(*5  
long[] nStartPos; //开始位置 ys+?+dY2  
long[] nEndPos; //结束位置 #l;Ekjfz  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 pKEMp&geo  
long nFileLength; //文件长度 nkhM1y  
boolean bFirst = true; //是否第一次取文件 BD4.sd+H,  
boolean bStop = false; //停止标志 BC@"WlD  
File tmpFile; //文件下载的临时信息 aE,x>I 7 D  
DataOutputStream output; //输出到文件的输出流 /f%u_ 8pV%  
bL0+v@(r  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) DMf^>{[  
public SiteFileFetch(SiteInfoBean bean) throws IOException d_5h6C z4  
{ NPB':r-8  
siteInfoBean = bean; NLz$jk%=g  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Qs% f6rL  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); &`>*3m(  
if(tmpFile.exists ()) l*X5<b9  
{ 6h+/C]4  
bFirst = false; 2"__jp:(  
read_nPos(); rEAPlO.Yp  
} +\:I3nKs%  
else r4D66tF  
{ _R5^4-Qe  
nStartPos = new long[bean.getNSplitter()]; ;F5B)&/B  
nEndPos = new long[bean.getNSplitter()]; >wMsZ+@m  
} <5$= Ta  
<NJ7mR}  
ppV\FQ{K  
Ce_Z &?  
} FswFY7 8  
cz T@txF  
dk(-yv'  
public void run() v(: VUo]H  
{ Zfb:>J@h6  
//获得文件长度 n]j(tP  
//分割文件 #=O0-si ]P  
//实例FileSplitterFetch B;K{Vo:C  
//启动FileSplitterFetch线程 |(P>'fat-p  
//等待子线程返回 e#zGLxa  
try{ klch!m=d  
if(bFirst) J2 5>t^  
{ jzPC9  
nFileLength = getFileSize(); CJu;X[6  
if(nFileLength == -1) gdT^QM:y4$  
{ x_@ev-  
System.err.println("File Length is not known!"); fmSw%r|pT  
} $C[YqZO  
else if(nFileLength == -2) a,j!B hu  
{ uWfse19  
System.err.println("File is not access!"); U| N`X54  
} 6B+ @76wH  
else a:;*"p[R  
{ Y7{|EI+@  
for(int i=0;i<nStartPos.length;i++) pt0H*quwI  
{ ol[{1KT{  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); VX>_Sp s  
} yRgo1ow]  
for(int i=0;i<nEndPos.length-1;i++) vuAAaKz  
{ g|+G(~=e|  
nEndPos = nStartPos[i+1]; 17 j7j@s)  
} ]&r/H17  
nEndPos[nEndPos.length-1] = nFileLength; N{q'wep  
} -d[x 09  
} S`6'~g  
V)a6H^l  
& 9?vQq|%  
//启动子线程 C8t+-p  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; )Z; Y,g  
for(int i=0;i<nStartPos.length;i++) qC 6Q5F  
{ w}(xs)`num  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [p7le8=  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), !t_,x=  
nStartPos,nEndPos,i); DC$ S. {n  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); t TmFJ5  
fileSplitterFetch.start(); C$%QVcf  
} UfkRY<H  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), #|CG %w  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); PO}Q8Q3  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ow$#kQ&R O  
nEndPos = " + nFileLength); @O3w4Zs  
// fileSplitterFetch[nPos.length-1].start(); w_{z"VeD  
+}Q4 g]M8  
c:$:j,i}  
//等待子线程结束 #m M&CscE  
//int count = 0; oVhw2pKpM  
//是否结束while循环 4sJx_Qi  
boolean breakWhile = false; J%A`M\  
\hq8/6=4s  
sZbzY^P  
while(!bStop) O%)9t FT  
{ VAthQ<  
write_nPos(); +<q^[<pS  
Utility.sleep(500); B!N807  
breakWhile = true; NrU -%!Aw  
BT#>b@Xub  
^Qr P.l#pZ  
for(int i=0;i<nStartPos.length;i++) 3jn@ [ m  
{ %-*vlNC)  
if(!fileSplitterFetch.bDownOver) *K98z ?  
{ tEEhSG)s%  
breakWhile = false; KW;xlJz(j  
break; ~::R+Lh(  
} fwnpmuJ  
} Sx~_p3_5U  
if(breakWhile)  HOD2/  
break; tFSdi. |G=  
d,[KcX  
9D| FqU |  
//count++; R utW{wh  
//if(count>4) 5\'%zZ,l  
// siteStop(); +Va?wAnr  
} g764wl  
WR-C_1-pT  
I{AU,  
System.err.println("文件下载结束!"); BJq}1mn*  
} kg61Dgu  
catch(Exception e){e.printStackTrace ();} ;`+RSr^8$  
} M$?6 '  
.J@[v  
nn   
//获得文件长度 EGDE4n5>I  
public long getFileSize() C&st7. (k  
{ `MwQ6%lf  
int nFileLength = -1; $oQsh|sTI  
try{ 6P~"7k  
URL url = new URL(siteInfoBean.getSSiteURL()); hHg g H4T  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &59#$LyH`%  
httpConnection.setRequestProperty("User-Agent","NetFox"); 5HIpoj;\(  
b mm@oi  
'?>eW 2d  
int responseCode=httpConnection.getResponseCode(); 1h#k&r#*3  
if(responseCode>=400) qN0#=X  
{ Y1'.m5E  
processErrorCode(responseCode); I>3]4mI*a  
return -2; //-2 represent access is error 8k1 r|s@d  
} ygW@[^g  
#-Rz`Y<&  
aK&+p#4t  
String sHeader; 0C p}  
oU@ljSD  
F^NR qE  
for(int i=1;;i++) ZYt __N  
{ 55cldo   
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ]6;AK\9TM  
//Utility.log(in.readLine()); X@:fW  @  
sHeader=httpConnection.getHeaderFieldKey(i); /T(\}Z  
if(sHeader!=null)  ke#;1  
{ 4@V] zfu^Q  
if(sHeader.equals("Content-Length")) L@_">' pR  
{ &+j^{a  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 3.0c/v5Go  
break; p<zXuocQ  
} cGc|n3(  
} LJ/qF0L!H  
else ^0|NmMJ]  
break; 7 h1"8#X  
} uBTT {GGQ  
} m3(T0.j0P  
catch(IOException e){e.printStackTrace ();} -n *>zGc  
catch(Exception e){e.printStackTrace ();} 9$,gTU_a  
Tb= {g;0 @  
M96( Rg  
Utility.log(nFileLength); 9i<-\w^$  
_o?(t\B9{  
h*KHEg"+  
return nFileLength; a-E-hX2  
} z;C=d(|nN  
.lBY"W&{  
|3,V%>z  
//保存下载信息(文件指针位置) |3s&Y`x-D  
private void write_nPos() iW}l[g8sw!  
{ J=X% xb  
try{ 4LEE /  
output = new DataOutputStream(new FileOutputStream(tmpFile)); NN 6KLbC(  
output.writeInt(nStartPos.length); :2pBv#\"qk  
for(int i=0;i<nStartPos.length;i++) `,Nn4  
{ LZ)m](+M  
// output.writeLong(nPos); oe |e+  
output.writeLong(fileSplitterFetch.nStartPos); iHn!KV  
output.writeLong(fileSplitterFetch.nEndPos); i"]8Zw_D  
} 1mJ_I|98  
output.close(); DjzUH{6O  
} ' f$L  
catch(IOException e){e.printStackTrace ();} 7F(F.ut  
catch(Exception e){e.printStackTrace ();} S9NN.dKu  
} :dguQ|e  
b!X"2'  
6eT'[Umx  
//读取保存的下载信息(文件指针位置) GWInN8.5  
private void read_nPos() | NU0tct^  
{ qysa!B  
try{ #a |ch6B  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); kLVn(dC "  
int nCount = input.readInt(); paNw5] -  
nStartPos = new long[nCount]; O_Rcd&<mr  
nEndPos = new long[nCount]; U[QD!  
for(int i=0;i<nStartPos.length;i++)  aoDD&JE  
{ 7+a%ehwU  
nStartPos = input.readLong(); F>QT|  
nEndPos = input.readLong(); "Wk{4gS7l  
} r^A#[-VyNP  
input.close(); `SjD/vNE  
} [b.'3a++  
catch(IOException e){e.printStackTrace ();} BO4 K#H7  
catch(Exception e){e.printStackTrace ();} 9J7J/]7f  
} uUz`=4%A  
! F <] T  
8F^,8kIR  
private void processErrorCode(int nErrorCode) RF5q5<0  
{ |R;l5ZKvV  
System.err.println("Error Code : " + nErrorCode); +F o$o  
} em1cc,  
%L j0  
%x6Ov\s2  
//停止文件下载 k9) u 3  
public void siteStop() i6md fp|k  
{ 5 Y Q  
bStop = true; 1_NG+H]x9  
for(int i=0;i<nStartPos.length;i++) Z|(c(H2  
fileSplitterFetch.splitterStop(); "Ug/ ',jkV  
D*cyFAF  
#<wpSs  
} S&3X~jD(1  
} rj,K`HD  
//负责部分文件的抓取 %XI"<Y\yL  
**FileSplitterFetch.java Wzqb>.   
*/ `(,*IK a  
package NetFox; {@V3?pG?p  
$% Ci8p  
qo6LC>Qg  
import java.io.*; 3kiE3*H  
import java.net.*; 9Yl8n dP^E  
a_{io`h3&  
0TO_1 0D  
public class FileSplitterFetch extends Thread { eOehgU5x  
R6!cK[e]4  
5e)6ua,  
String sURL; //File URL 2 {e dW+  
long nStartPos; //File Snippet Start Position 7-d}pgVK  
long nEndPos; //File Snippet End Position VyWYfPK  
int nThreadID; //Thread's ID ov`^o25f  
boolean bDownOver = false; //Downing is over q#99iiG1  
boolean bStop = false; //Stop identical JOrELrMx  
FileAccessI fileAccessI = null; //File Access interface =_RcoG/^~  
N^\2 _T  
u  m: 0y,  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException LZr0]g{Pu/  
{ G#e9$!  
this.sURL = sURL; (!*Xhz,(-  
this.nStartPos = nStart; KQ4kZN  
this.nEndPos = nEnd; Pr5g6I'G   
nThreadID = id; *p&^!ct  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 m_m8c8{Y  
} :}@C9pqr2  
2.LJp}>  
#zS1Z f^KP  
public void run() Vvm=MBgN  
{ QqiJun_m  
while(nStartPos < nEndPos && !bStop) nn@^K6  
{ 7m:|u*ij2~  
o_Jn_3=  
v /R[?H)  
try{ b0@>xT  
URL url = new URL(sURL); .tRr?*V|l  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Ot`LZ"H:  
httpConnection.setRequestProperty("User-Agent","NetFox"); F qeV3 N  
String sProperty = "bytes="+nStartPos+"-"; {f+N]Oo*  
httpConnection.setRequestProperty("RANGE",sProperty); v2hZq-q  
Utility.log(sProperty); *jM_wwG  
YDQ:eebg(  
gA~20LSt  
InputStream input = httpConnection.getInputStream(); K(nS$x1G  
//logResponseHead(httpConnection); M{?zvq?d  
erx 5j\  
~;M)qR?]W  
byte[] b = new byte[1024]; gjj 93  
int nRead; JEWL)  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) d/D,P=j"  
{  0]AN;  
nStartPos += fileAccessI.write(b,0,nRead); (C daE!I4Q  
//if(nThreadID == 1) 48 W.qzC  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); BBHK  
} fdlvn*H  
D \N \BD  
q$r&4s)To  
Utility.log("Thread " + nThreadID + " is over!"); sl/=g   
bDownOver = true; z Yw;q3"  
//nPos = fileAccessI.write (b,0,nRead); t})lr\  
} EL^8zyg%%  
catch(Exception e){e.printStackTrace ();} ))7LE|1l  
} ;LCTCt`  
} LHh5 v"zjG  
vQ:wW',i  
>i "qMZ  
//打印回应的头信息 OT%0{2c"]  
public void logResponseHead(HttpURLConnection con) C5P$ &s\  
{ E {tx/$f  
for(int i=1;;i++) g;pR^D'M5C  
{ jY7=mAd  
String header=con.getHeaderFieldKey(i); *YWk1Cwjo  
if(header!=null) 00ofHZ  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ?4XnEDA m  
Utility.log(header+" : "+con.getHeaderField(header)); %.mEBI=hs  
else W'a(oI  
break; V=pMq?Nr  
} TG}d3ZU !  
} M!1U@6n!=)  
j'K38@M:MN  
F{<5aLaYti  
public void splitterStop() -?s&pKi  
{ yuOS&+,P  
bStop = true; veeI==]  
} WRW WskP  
4&QUh+F  
Nln`fE/Ht  
} 5W/{h q8}}  
-LtK8wl^  
m9in1RI%  
/* pkJ/oT  
**FileAccess.java 57wFf-P  
*//文件访问(定位,写) <aJ $lseG  
package NetFox; ,`k _|//}=  
import java.io.*; K]c4"JJ  
kb71q:[  
O] Y v   
public class FileAccessI implements Serializable{ {C3U6kKs;R  
ui:=  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 !/`$AXO  
RandomAccessFile oSavedFile; V YZU eh  
long nPos; r9# \13-  
bLzs?eos  
Mi+H#xx16  
public FileAccessI() throws IOException 0Vkl`DmeM.  
{ e  ^Ds  
this("",0); 'Gx$Bj  
} NYwR2oX  
!\FkG8  
+oI3I~  
public FileAccessI(String sName,long nPos) throws IOException F]UQuOR)  
{ %SrM|&[  
oSavedFile = new RandomAccessFile(sName,"rw"); j9d!yW  
this.nPos = nPos; >I}9LyZt  
oSavedFile.seek(nPos); xl(@C*.sC1  
} `s|]"'rX  
<Mx0\b!  
[}OgSP9i  
public synchronized int write(byte[] b,int nStart,int nLen) :_ROJ  
{ %f j+70  
int n = -1; {%C*{,#+8q  
try{ LCs__.  
oSavedFile.write(b,nStart,nLen); [U>@,BH  
n = nLen; .Obn&S  
} !M7<BD};  
catch(IOException e) K_~h*Yc  
{ <[Q3rJ  
e.printStackTrace (); Xd<t5{bD!  
} S4N(cn&  
('O}&F1  
D-2.fjo9!  
return n; +x=)/;:  
} 33'Y[4  
"T2"]u<52  
eujK4s  
} :Zt2'vcGpf  
n(1')?"mA  
08s_v=cF  
/* lx |5?P  
**SiteInfoBean.java ,E;;wdIt  
*/ )?=YT  
package NetFox; ,HB2 hHD  
|l0Ea  
b>\?yL/%+?  
public class SiteInfoBean { zce`\ /:  
U!(@q!>G  
{D`'0Z1"  
private String sSiteURL; //Site's URL )w h%|  
private String sFilePath; //Saved File's Path |&3x#1A  
private String sFileName; //Saved File's Name P`$!@T0=  
private int nSplitter; //Count of Splited Downloading File JhHWu<  
t23'x0l  
^03j8Pc-c  
public SiteInfoBean() lDc-W =X=  
{//nSplitter的缺省值为5 fB1TFtAh  
//default value of nSplitter is 5 KS}hU~  
this("","","",5); ^/U27B  
} ke_ [  
`'I{U5;e  
]:(W_ qEA  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) omSM:f_~  
{ "{D6J809  
sSiteURL= sURL; aE"[5*a  
sFilePath = sPath; G{Yz8]m  
sFileName = sName; 3S*AxAeg  
this.nSplitter = nSpiltter; y [#pC<^  
 =<}<Ny  
K+*Q@R D  
} ;5_{MCPM  
m)v''`9LU  
"_|oWn  
public String getSSiteURL() j.e0;! (L}  
{ hR#-u1C  
return sSiteURL; F&RgT1*  
} L< ^j"!0  
= ?D(g  
tVuWVJ4M  
public void setSSiteURL(String value) _"@CGXu  
{ ;0rGiWC#  
sSiteURL = value; 'e)^m}:?D  
} j/`94'Y  
k%s_0 @  
a"N4~?US  
public String getSFilePath() Y;4!i?el  
{ ldha|s.*  
return sFilePath; r;BT,jiX  
} +mj*o(  
te|? )j  
d^03"t0O]  
public void setSFilePath(String value) N`@NiJ(O;  
{ N;Dp~(1 J1  
sFilePath = value; >F1kR\!  
} (jjTK'0[  
{7u[1[L1  
j#r6b]k(Hv  
public String getSFileName() YHNR 3  
{ `?T#Hl>j  
return sFileName; d) f@ 5/<  
} Y3.$G1{#0w  
Hnknly  
r{\1wt  
public void setSFileName(String value) >r`b_K  
{ dzLQI}89+k  
sFileName = value; \B F*m"lz  
} 1"Z@Q`}  
j /=i Mq  
CTX9zrY*T  
public int getNSplitter() |-sPLU&s%  
{ -9N@$+T  
return nSplitter; S/|,u`g-  
} :B3[:MpL}  
j',W 64  
k@zy  
public void setNSplitter(int nCount) v+p {|X-  
{ d->|EJP  
nSplitter = nCount; XO#/Fv!  
} ;g{qYj_  
} !!@A8~H  
valtev0<  
L,y6^J!  
/* {{V8;y  
**Utility.java ! cKz7?w  
*/ =q N2Xg/  
package NetFox; rpeJkG@+  
SJD@&m%?[  
u\&b4=nL  
public class Utility { P96pm6H_;  
+]=e;LN$0  
8.F~k~srA  
public Utility() F, U*yj  
{ SGb;!T *  
J>fQNW!{  
+"9hWb5  
} g^*<f8 ~d  
+)JpUqHa  
//线程睡眠 h(WrL  
public static void sleep(int nSecond) dJ$"l|$$  
{ zdXkR]  
try{ $kR N h6  
Thread.sleep(nSecond); OL4z%mDZi  
} %$%& m1Y  
catch(Exception e) {U&.D [{&  
{ vJAZ%aW  
e.printStackTrace (); <ZU=6Hq  
} Gt9&)/#  
} /cc\fw1+  
o7IxJCL=Q  
//日志  hi g2  
public static void log(String sMsg) * #TUGfwy  
{ .<kqJ|SVi  
System.err.println(sMsg); KNH1#30 K  
} v<Bynd-  
ECv)v  
l5L.5 $N  
public static void log(int sMsg) ^vG8#A}]  
{ 6e&>rq6C  
System.err.println(sMsg); >0Q|nCx  
} ~]ZpA-*@Ut  
} N !TW!  
(O0Urm  
R|i/lEq  
/* H'Yh2a`!o  
**TestMethod.java  i2~  
*/ 4CGPO c  
package NetFox; o|jIM9/  
J\ e+}{  
JN7k2]{  
public class TestMethod { N},n `Yl.  
@&[T _l  
@A)R_p  
public TestMethod() /x3/Ubmz~x  
{ ///xx/weblogic60b2_win.exe l<M'=-Y  
try{ hYawU@R  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Ef<b~E@  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); \QmCeB  
SiteFileFetch fileFetch = new SiteFileFetch(bean); IIy~[4dW  
fileFetch.start(); `^lYw:xA  
} S_~z-`;h!  
catch(Exception e){e.printStackTrace ();} Nj(" |`9"  
>E*$ E  
Bn>8&w/P  
} `a9L%z  
eb*#'\~'  
~o n(3|$  
public static void main(String[] args) ayAo^q  
{ >}(CEzc8  
new TestMethod(); p !s}=wI `  
} ! !PYP'e  
} #A]-ax?Qc}  
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