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http断点续传简单实现(java)

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/*  ]P(:z  
**SiteFileFetch.java ly}6zOC\  
*/ yd`xmc)  
package NetFox; v6HBO#F'V{  
import java.io.*; iT%aAVs  
import java.net.*; Va\dMv-b  
qWGnIPk  
n(/(F `  
public class SiteFileFetch extends Thread { R(kr@hM  
_,=A\C_b@  
@~U: |h  
SiteInfoBean siteInfoBean = null; //文件信息Bean 92WvD  
long[] nStartPos; //开始位置 >1,.4)k%K  
long[] nEndPos; //结束位置 XN5EZ#  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 8*H-</ =  
long nFileLength; //文件长度 vmvk  
boolean bFirst = true; //是否第一次取文件 m7zen530  
boolean bStop = false; //停止标志 rF2`4j&!  
File tmpFile; //文件下载的临时信息 Ps+0qqT*  
DataOutputStream output; //输出到文件的输出流 tjBs>w  
rC14X}X6  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) (8qMF{  
public SiteFileFetch(SiteInfoBean bean) throws IOException 5CueD]  
{ yN5g]U. Q  
siteInfoBean = bean; 4cRF3$a md  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); $}jp=?,t  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 'LpJ:Th  
if(tmpFile.exists ()) tlV>  
{ Q'~kWmLf  
bFirst = false; >t)vQ&:;u  
read_nPos(); U>IllNd  
} !Sy._NE`z  
else Y _m4:9p  
{ P \tP0+at  
nStartPos = new long[bean.getNSplitter()]; dD?1te  
nEndPos = new long[bean.getNSplitter()]; ';hU&D;s  
} lt|\$Iy(  
o=_:g >5  
T,@.RF  
68Vn]mr#  
} }7RR",w  
=\B{)z7@6D  
wV+ W(  
public void run() D!h8NZ;El  
{ B&Q\J>l9S  
//获得文件长度 !lKO|Y  
//分割文件 +J} wYind  
//实例FileSplitterFetch R5g -b2Lm  
//启动FileSplitterFetch线程 y{,HpPp#o  
//等待子线程返回 "fdgBso  
try{ A07g@3n  
if(bFirst) --d<s  
{ ;gY W!rM  
nFileLength = getFileSize(); =MEv{9_  
if(nFileLength == -1) F^ 7qLvh  
{ K~H)XJFF  
System.err.println("File Length is not known!"); K:Wxx "  
} i6?,2\K  
else if(nFileLength == -2) %%`Nq&'  
{ #:s*)(Qn  
System.err.println("File is not access!"); [4"1TyW  
} [mn@/qf  
else AqB5B5}  
{ nT..+ J)  
for(int i=0;i<nStartPos.length;i++) _T&?H&#  
{ NZdjS9  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); R  5-q{  
} <k<K"{  
for(int i=0;i<nEndPos.length-1;i++) KtchK pv  
{ =dx!R ,Bw  
nEndPos = nStartPos[i+1]; _Db=I3.HJ  
} CL.JalR`b  
nEndPos[nEndPos.length-1] = nFileLength; K#rfQ0QK/!  
} OSQZ5:g|  
} S<rdPS*P  
au@ LQxKQ  
,;)Y 1q}Q  
//启动子线程 }l~|c{WH`  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; L^i=RGx  
for(int i=0;i<nStartPos.length;i++) Nz_c]3_j  
{ 7cW9@xPe  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), X ,n4_=f  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), cjAKc|NJ  
nStartPos,nEndPos,i); T6h-E^Z  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ."&,_F  
fileSplitterFetch.start(); id<i|  
} SNV~;@(h  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), )Fx"S.Ok  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 9]fhH  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", M(|Qvh{Q6  
nEndPos = " + nFileLength); v".q578 0B  
// fileSplitterFetch[nPos.length-1].start(); fftFNHP  
JQ=i{9iJ  
_x&;Fa%  
//等待子线程结束 eQu%TZ(x-$  
//int count = 0; <f.*=/]W2  
//是否结束while循环 gF-<%<RV  
boolean breakWhile = false; Zu`; S#Y  
h6<abT@I  
~T@t7Cg  
while(!bStop) BZejqDr*  
{ |z\5Ik!fF]  
write_nPos(); |x@)%QeC  
Utility.sleep(500); PtCO';9[  
breakWhile = true; NAjY,)>'K  
G6(k wv4  
Rt:k4Q   
for(int i=0;i<nStartPos.length;i++) Yv k Qh{  
{ d~F`q7F'?]  
if(!fileSplitterFetch.bDownOver) ^`~M f  
{ 2_M+akqy^  
breakWhile = false; rqW[B/a{  
break; Ls{z5*<FM  
} b&[9m\AX`  
} aSdh5?  
if(breakWhile) H e ABU(o4  
break; 7ksh%eV  
IhnHNY]<g  
LOQoi8j  
//count++; c.-h'1  
//if(count>4) A}WRpsA9  
// siteStop(); _a1 =?  
} WA}<Zme3[  
_J(n~"eR  
xxkU u6x#  
System.err.println("文件下载结束!"); /WlK*8C  
} nv&uhu/q  
catch(Exception e){e.printStackTrace ();} 1{+x >Pv:  
} g?N~mca$  
gw~ %jD-2  
bHVAa#  
//获得文件长度 (uW/t1  
public long getFileSize() qcMVY\gi  
{ i;Cs,Esnf  
int nFileLength = -1; pm$2*!1F(  
try{ K*iy^}  
URL url = new URL(siteInfoBean.getSSiteURL()); ,<?iL~> %  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); d\aKGq;8C  
httpConnection.setRequestProperty("User-Agent","NetFox"); u>c\J|K_V  
9rXbv4{  
w}+#w8hu  
int responseCode=httpConnection.getResponseCode(); 7jvy]5y8&~  
if(responseCode>=400) 8 2qf7`  
{ NbOeF7cq+  
processErrorCode(responseCode); j1 _ E^  
return -2; //-2 represent access is error j,%@%upM  
} xw_VK1  
vzV,} S*c  
n][/c_]q  
String sHeader; 3ThBy'  
06DT2  
} 8ZCWmd  
for(int i=1;;i++) 5v"r>q[ X  
{ Gr9/@U+  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); vSty.:bY\p  
//Utility.log(in.readLine()); X"WKgC g$  
sHeader=httpConnection.getHeaderFieldKey(i); T=r-6eN  
if(sHeader!=null) r=GF*i[3  
{ q/y4HT,x  
if(sHeader.equals("Content-Length")) MuNM)pyxp  
{ 5`qt82Qm  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ,XT#V\qne  
break; ,M2u (9  
} A4LGF  
} Z$ qFjWp  
else 3t<XbHF9  
break; U'^AJ2L8  
} +5J"G/f  
} 'J^ M`/  
catch(IOException e){e.printStackTrace ();} bwh7.lDAl  
catch(Exception e){e.printStackTrace ();} s ^NO(  
mF!/8qk   
[ZwZGAP  
Utility.log(nFileLength); yM dEH-?/  
`$og]Dn;  
zNSix!F  
return nFileLength; iVq4&X_x  
} @L^Fz$Sx  
.d< +-w2Mu  
<viIpz2jh%  
//保存下载信息(文件指针位置) u@|izRk  
private void write_nPos() aE}1~`  
{ R=M"g|U6  
try{ 0kN;SSX!  
output = new DataOutputStream(new FileOutputStream(tmpFile)); JA W}]:jC  
output.writeInt(nStartPos.length); blxAy  
for(int i=0;i<nStartPos.length;i++) .G[y^w)w}  
{ ,#3}TDC  
// output.writeLong(nPos); kp3(/`xP  
output.writeLong(fileSplitterFetch.nStartPos); y*2R#jTA  
output.writeLong(fileSplitterFetch.nEndPos); /dTy%hZC}  
} #PnuR2s7.  
output.close(); 5 e:Urv77  
} )6|7L)Dk  
catch(IOException e){e.printStackTrace ();} `(A6uakd  
catch(Exception e){e.printStackTrace ();} =PHl|^  
} 3/I Q]8g"  
$ tf;\R  
W- wy<<~f  
//读取保存的下载信息(文件指针位置) g*b 4N _  
private void read_nPos() [vki^M5i|Z  
{ ?]%JQ]Gf*  
try{ xsK{nM6g  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); :LRR\v0HM  
int nCount = input.readInt(); TJ(PTB;  
nStartPos = new long[nCount]; _'&N01  
nEndPos = new long[nCount]; A^7!:^%K  
for(int i=0;i<nStartPos.length;i++) VlKy6PSIg  
{ w+Ve T@  
nStartPos = input.readLong(); 8+vZ9!7  
nEndPos = input.readLong(); L'{;V\d  
} A.7:.5Cx'  
input.close(); lhg3 }dW  
} T!$7:% D  
catch(IOException e){e.printStackTrace ();} E_&Hje|J_[  
catch(Exception e){e.printStackTrace ();} ".L+gn}u-  
} 9fD4xkRS  
OJE<2:K  
k5G(7Ug=g~  
private void processErrorCode(int nErrorCode) >yvP[$]!6  
{ T=cSTS!P;q  
System.err.println("Error Code : " + nErrorCode); Rf@D]+v  
} ;SQ<^"eK  
\V@SCA'  
*Yv"lB8  
//停止文件下载 2&91C[da0  
public void siteStop() R_h(Z{d  
{ E [JXQ76  
bStop = true; 1A^iUC5)  
for(int i=0;i<nStartPos.length;i++) i} 96, {  
fileSplitterFetch.splitterStop(); PJj{5,#@3  
|| ?B1  
5A1oZ+C#  
} Rs B o\#`  
} EQPZV K/  
//负责部分文件的抓取 o;Ijv\Em  
**FileSplitterFetch.java 4W8rb'B!Ay  
*/ w?ssV  
package NetFox; IV^LYu  
dsDoPo0!  
5_Yv>tx  
import java.io.*; BOJ h-(>I  
import java.net.*; ~WuElns  
vl$! To9R"  
Wm:3_C +j  
public class FileSplitterFetch extends Thread { Pb?H cg  
_5a]pc$\Y]  
YVVX7hB  
String sURL; //File URL 7ka^y k@Q  
long nStartPos; //File Snippet Start Position i]GBu  
long nEndPos; //File Snippet End Position !s,<h U#  
int nThreadID; //Thread's ID c 5P52_@  
boolean bDownOver = false; //Downing is over R7*Jb-;$!  
boolean bStop = false; //Stop identical Wq)'0U;{$  
FileAccessI fileAccessI = null; //File Access interface A{h hnrr8  
, >Y. !  
dgssX9g37  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException $m/-E#I #Z  
{ <mHptgd,  
this.sURL = sURL; L1BpkB  
this.nStartPos = nStart; ]6OrL TmP  
this.nEndPos = nEnd; uuj"Er31  
nThreadID = id; N&NOh|YS  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 HY#7Ctn3  
} zc J]US  
;]fpdu{  
hgj#VY$B  
public void run() j>&n5?  
{ [2w3c4K  
while(nStartPos < nEndPos && !bStop) y- k?_$ M  
{ 4 E3@O  
,-  ]2s_  
c Yx=8~-  
try{ ZJ"*A+IJx[  
URL url = new URL(sURL); ==x3|^0y  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); qU8UKIP  
httpConnection.setRequestProperty("User-Agent","NetFox"); VR?7{3  
String sProperty = "bytes="+nStartPos+"-"; <6<uO\B\  
httpConnection.setRequestProperty("RANGE",sProperty); w :FH2*  
Utility.log(sProperty); &_4A6  
UTA0B&aB  
+lJuF/sS8m  
InputStream input = httpConnection.getInputStream(); 37p0*%a":  
//logResponseHead(httpConnection); #BS]wj2#  
B0p>'O2  
SUD]Wl7G`r  
byte[] b = new byte[1024]; =)M8>>l  
int nRead; -Kg@Sj/U}R  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 'lC"wP&$  
{ '5ky<  
nStartPos += fileAccessI.write(b,0,nRead); XyS#6D  
//if(nThreadID == 1) u4VQx,,  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ]&/jvA=\l,  
} R'dF<&Kj|  
3JW9G04.  
fH`1dU  
Utility.log("Thread " + nThreadID + " is over!"); C*Ws6s>+z  
bDownOver = true; BT>*xZLpS  
//nPos = fileAccessI.write (b,0,nRead); Aog 3d\1$  
} 0nx <f>n  
catch(Exception e){e.printStackTrace ();} 344,mnAd  
} j,/o0k,  
} W\.f:"2qr  
/<:9NP'^  
;x^&@G8W`  
//打印回应的头信息 H'gPGOd  
public void logResponseHead(HttpURLConnection con) lG# &Pv>-  
{ K'?ab 0  
for(int i=1;;i++) bG^eP :r  
{ Jr17pu(t  
String header=con.getHeaderFieldKey(i); 4n3QW%#  
if(header!=null) 2IjqT L  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); hN\E8"To  
Utility.log(header+" : "+con.getHeaderField(header)); ^Jnp\o>  
else R2]?9\II  
break; :NbD^h)R  
} O.rk!&N  
} v@>hjie  
h(/|`   
] (MXP,R  
public void splitterStop() 7h&xfrSrD  
{ t ?bq ~!X  
bStop = true; /SMp`Q88  
} S\0"G*  
:\80*[=;Z  
*otJtEI>6  
} Yf{s0Z  
W@wT ,yJ8@  
Gw+z8^|C&}  
/*  EVq<gGy  
**FileAccess.java S}Mxm 2  
*//文件访问(定位,写) !@VmaAT  
package NetFox; Kjz,p^Y\  
import java.io.*; $ya#-pi`;  
{g/\5Z\b  
Z?nMt  
public class FileAccessI implements Serializable{ Tr@`ozp8  
? 5B}ZMW  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 AO']Kmm  
RandomAccessFile oSavedFile; 5yA^n6  
long nPos; uaU!V4-  
7ZZSAI  
2A`EFk7_X  
public FileAccessI() throws IOException P45q}v  
{ ke3=s  
this("",0); *EV]8  
} _^a.kF  
/_}v|E0  
H>M%5bj  
public FileAccessI(String sName,long nPos) throws IOException (^Nf;E  
{ &q":o 'q  
oSavedFile = new RandomAccessFile(sName,"rw"); hJd#Gc~*M  
this.nPos = nPos; 2o\\qEYg  
oSavedFile.seek(nPos); up:e0di{  
} o.Cj+`0}5  
i(c2NPbX  
Q;aZpi-E"  
public synchronized int write(byte[] b,int nStart,int nLen) E#HO0 ]S  
{ &)bar.vw/  
int n = -1; %{HqF>=~  
try{ /@wm?ft6Gk  
oSavedFile.write(b,nStart,nLen); wh*OD  
n = nLen; l,v:[N  
} Qy6Avw/$  
catch(IOException e) ,%KB\;1mn'  
{ ( j-(fS  
e.printStackTrace (); >Mvt;'c  
} ^2mXXAQf7^  
}>Os@]*'^(  
w:umr#  
return n; *:&fw'vd,  
} @#T?SNIL5  
p O: EJ  
x&9 I2"  
} <c\aZ9+V  
B]Zsn`n  
LG,RF:  
/* e,4!/|H:  
**SiteInfoBean.java =r_ S MTu  
*/ x65e,'  
package NetFox; N`zHe*=[~  
g:2/!tujL  
mB1)!  
public class SiteInfoBean { rBny*!n  
BR0bf5T/  
9s7B1Pf  
private String sSiteURL; //Site's URL Pu9.Uwx  
private String sFilePath; //Saved File's Path XkK16aLE  
private String sFileName; //Saved File's Name &[Sw:{&*jv  
private int nSplitter; //Count of Splited Downloading File KX9ZwsC0  
/4T%&#6s  
?v")Z 0 ~  
public SiteInfoBean() 94a _ W9  
{//nSplitter的缺省值为5 3aDma/  
//default value of nSplitter is 5 |2oB3 \)/  
this("","","",5); +QHhAA$  
} >K &b,o,[  
S((8DSt*  
gq0gr?  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) V!Joh5=a  
{ ' l!QGKz  
sSiteURL= sURL; lhjPS!A~  
sFilePath = sPath; bX6*/N  
sFileName = sName; D^TKv;%d  
this.nSplitter = nSpiltter; _n_i*p '2  
F_21`Hj  
o3W5FHFAv  
} u#P7~9ZG-  
'PO1{&M  
4o=G) KO{  
public String getSSiteURL() X'u`\<&W  
{ |j!D _j#U  
return sSiteURL; 4 B> l|%  
} /z'j:~`E  
R1 wd Q8q  
4({=(O  
public void setSSiteURL(String value) ,>g 6OU2~6  
{ .6'T;SoK>  
sSiteURL = value; J`V6zGgW  
} 3{c&%F~!  
*FAg^G&1  
N&ddO-r[s  
public String getSFilePath() WI6er;D  
{ K{iay g!k  
return sFilePath; *1%g=vb  
} {Ise (>V  
\ agC Q&  
?3|ZS8y  
public void setSFilePath(String value) eU12*(  
{ )l"0:1Ig  
sFilePath = value; S4(IYnwN  
} S_QDYnF)`  
t^[{8,N  
 I&v B\A  
public String getSFileName() ~kHir]jc  
{ ;zOZu~Q|'  
return sFileName; Qz<-xe`o8]  
} Hc+<(g   
S2NsqHJr  
bHMlh^{`%  
public void setSFileName(String value) _9-Ajv  
{ ]I]dwi_g)  
sFileName = value; _ <~05Eh  
} '0=U+Egp  
4 '+)9&g  
~W#f,mf  
public int getNSplitter() $K iMu  
{ kQb0pfYs  
return nSplitter; QxkfP%_g  
} :C&?(HJ&r  
af_zZf!0  
4R0_%x6vG  
public void setNSplitter(int nCount) t"L:3<U7  
{ \Dc\H )  
nSplitter = nCount; e Jwr  
} L"Gi~:z  
} *[U:'o `67  
q+DH2&E'  
fg9sZ%67]\  
/* _I!Xr!!)a0  
**Utility.java & p%,+|  
*/ z=xHk|+'  
package NetFox; h}oQr0"c  
'L m `L<`  
G'epsD,.bX  
public class Utility { b'&pJ1]]}  
j NY8)w_  
[X I5Bu ~  
public Utility() Cse0!7_T  
{ _E%[D(  
mSzwx/3"  
w iq{ Jo#  
} EW!$D  
AVJk  
//线程睡眠 tL5Xfd?u  
public static void sleep(int nSecond) }/LYI  
{ I*ej_cFQ^  
try{ _c&*'IY[V  
Thread.sleep(nSecond); 4EpzCaEZ  
} Za} |Ee  
catch(Exception e) m^=, RfUUd  
{ V ": BAn  
e.printStackTrace (); S ~_%  
} I45A$nV#Q  
} {)[i\=,`{  
ceOjuzY  
//日志 ^AM_A>HnG  
public static void log(String sMsg) :b>|U"ux  
{ q5 A+%#  
System.err.println(sMsg); ELPJ}moWZ  
} RgO 7> T\  
~L1O\V i  
lVFX@I=pI  
public static void log(int sMsg) ^"Y'zI L  
{ {$t*Mb0  
System.err.println(sMsg); BuYDw*.  
} W(8g3  
} {aL$vgYT1  
:}-u`K*  
NWg\{a  
/* cjR.9bgn  
**TestMethod.java W wE)XE  
*/ WU4i-@Bm8  
package NetFox; sHuz10  
V588Leb?  
qh'BrYu*  
public class TestMethod { JA}'d7yEa  
^ZlV1G;/W@  
g#:XN  
public TestMethod() F:g{rm[  
{ ///xx/weblogic60b2_win.exe 3azc`[hl  
try{ )eEvyU  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); :6/OU9f/R  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); VqrMi *W6  
SiteFileFetch fileFetch = new SiteFileFetch(bean); P~<93  
fileFetch.start(); d{hYT\7~1(  
} G"[pr%?  
catch(Exception e){e.printStackTrace ();} l!  y _P  
D5>~'N3b  
(0Qq rNs  
} J9FNjM[qe  
5jQP"^g  
Fdw[CYHz  
public static void main(String[] args) ."X~?Nk  
{ de6dLT>m  
new TestMethod(); nnNg^<[k3  
} t4*A+"~j  
} %MJ7u}  
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