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http断点续传简单实现(java)

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/* t?]6>J_V  
**SiteFileFetch.java ]Nvtiw 6  
*/ y=\jQ6Fc  
package NetFox; Tc)T0dRP  
import java.io.*; %f&(U/  
import java.net.*; morI'6N  
| pp  @  
HJ5m5':a  
public class SiteFileFetch extends Thread { lq_W;L  
dTaR 8i  
j78xMGKO  
SiteInfoBean siteInfoBean = null; //文件信息Bean GD'C^\E aZ  
long[] nStartPos; //开始位置 .VmI4V?}h  
long[] nEndPos; //结束位置 ZjEO$ ts=@  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 5 ^iU1\(L  
long nFileLength; //文件长度 B<[;rk  
boolean bFirst = true; //是否第一次取文件 }FMl4 _}u  
boolean bStop = false; //停止标志 IO xj$?%l  
File tmpFile; //文件下载的临时信息 -& kQlr  
DataOutputStream output; //输出到文件的输出流 KF'H|)!K  
*4qsM,t  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) -H`G6oMOO  
public SiteFileFetch(SiteInfoBean bean) throws IOException R\:C|/6f  
{ [ylGNuy  
siteInfoBean = bean; VSZ6;&2^  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); RQ{w`> K  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); S/d})8~.  
if(tmpFile.exists ()) Xt= &  
{ i&>,aiH@  
bFirst = false; gH\r# wy|  
read_nPos(); 0 \LkJ*i  
} =pcj{B{qa  
else >Fld7;L?<  
{ d!KX.K\NM,  
nStartPos = new long[bean.getNSplitter()]; BdO$  
nEndPos = new long[bean.getNSplitter()]; 45j+n.9=  
} OqBw&zm  
hDlk! #*  
R C (v#G  
AD?DIE(v  
} q 8=u.T  
bOck^1Hky  
/2dK*v0  
public void run() p!aeL}g`  
{ g-p OO/|  
//获得文件长度 f/;\/Q[Z7  
//分割文件 45MK|4\Y_  
//实例FileSplitterFetch t48(GKF  
//启动FileSplitterFetch线程 +H&_Z38n  
//等待子线程返回 iW"L!t#\|  
try{ 1wc -v@E  
if(bFirst) +zs6$OI]V  
{ 6eDIS|/  
nFileLength = getFileSize(); N@MeaO  
if(nFileLength == -1) 0!vC0T[  
{ 3^Yk?kFE  
System.err.println("File Length is not known!"); \;7DS:d@  
} FOk @W&  
else if(nFileLength == -2) M+hc,;6  
{ jq0tMTb%L  
System.err.println("File is not access!"); 0"2 [I  
} 5h:SH]tn8]  
else M@'V4oUz  
{ %&_(IY$d  
for(int i=0;i<nStartPos.length;i++) ($S{td;  
{ ^ Nsl5  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); @5?T]V g  
} Q5,@ P?  
for(int i=0;i<nEndPos.length-1;i++) H;sQ]:.*]  
{ R ^B2J+O  
nEndPos = nStartPos[i+1]; @i{JqHU"  
} 3K?0PRg  
nEndPos[nEndPos.length-1] = nFileLength; mzT} C&hfP  
} )b%c]!  
} "{x~j \<  
K%pmE?%,8  
"}OFwes  
//启动子线程 q5vs;,_ |  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; /2@%:b)  
for(int i=0;i<nStartPos.length;i++) >|Jw,,uf  
{ 4|$D.`Wu  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 0[1 !K&(L  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), d(@A  
nStartPos,nEndPos,i); +1)C&:  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); g?>AY2f[5  
fileSplitterFetch.start(); /5x `TT  
} r0 X2cc  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), o`77gkLO  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); *}_/:\v  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", @zJI0_Bp  
nEndPos = " + nFileLength); BL8\p_U  
// fileSplitterFetch[nPos.length-1].start(); i `>X5Da5  
k( g$_ ]X  
7&At _l_  
//等待子线程结束 sN C?o[9l!  
//int count = 0; EkL\~^  
//是否结束while循环 nUd\4;J#  
boolean breakWhile = false; *b)b#p  
`U g.c  
6#KI? 6  
while(!bStop) Dz50,*}J  
{ *cf"l  
write_nPos(); 8zc!g|5"  
Utility.sleep(500); + kF[Oh#  
breakWhile = true; Un/fP1  
%b{!9-n}  
^ Wl/  
for(int i=0;i<nStartPos.length;i++) c}QJ-I   
{ aqM_t  
if(!fileSplitterFetch.bDownOver) !n{c#HfG  
{ Yjl0Pz .q  
breakWhile = false; }-L@AC/\#  
break; 5{g9Wh[  
} d_,tXV"z&  
} m@,>d_|-K-  
if(breakWhile) g \-3c=X  
break; epbp9[`  
=a!6EkX *  
pMquu&Td  
//count++; V1:3  
//if(count>4) ]T51;j'48  
// siteStop(); <kSaSW  
} h]Oplp4 \W  
_B1uE2j9  
"B}08C,?  
System.err.println("文件下载结束!"); -*lP1Nbp  
} {^f0RGJg9  
catch(Exception e){e.printStackTrace ();} >Y+KL  
} D9C}Dys  
Cv~hU%1T  
Qf|}%}% fp  
//获得文件长度 1hviT&  
public long getFileSize() VjqdKQeVq  
{ S1zw'!O5  
int nFileLength = -1; 4sj%:  
try{ nwo!A3w:  
URL url = new URL(siteInfoBean.getSSiteURL()); IA^)`l7H  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 7S2F^,w  
httpConnection.setRequestProperty("User-Agent","NetFox"); |+:ZO5FaO  
D%idlL2%J  
>>bYg  
int responseCode=httpConnection.getResponseCode(); oPy zk7{  
if(responseCode>=400) ]R{"=H'  
{ +2}(]J=-  
processErrorCode(responseCode); fE*I+pe  
return -2; //-2 represent access is error | q16%6q  
} \z`d}\3( R  
8-5 jr_*  
mG~y8nUtp  
String sHeader; qE72(#:R*  
m[{&xF|_  
DP_Pqn8p&M  
for(int i=1;;i++) arLl8G[  
{ (<C%5xk  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 6h_k`z  
//Utility.log(in.readLine()); |<|,RI?  
sHeader=httpConnection.getHeaderFieldKey(i); 0:Y`#0qK  
if(sHeader!=null) <u?hdwW \  
{ \.1b\\  
if(sHeader.equals("Content-Length")) #@6L|$iX  
{ c2\vG  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); )Zf}V0!?+  
break; N#)VD\m  
} $l;tP  
}  DiQkT R  
else  GQ0(&I  
break; % B &?D@  
} I*t)x,~3  
} ~9 WJrRWB  
catch(IOException e){e.printStackTrace ();} ,Q#tA|:8j  
catch(Exception e){e.printStackTrace ();} '<=MhNh\  
/C"s_:m;3  
fF>qU-  
Utility.log(nFileLength); YaZt+WA  
I!7.fuO  
W:poUG1UR  
return nFileLength; /e sk  
} K2rS[Kdfaq  
z83:a)U  
A4Q)YY9~  
//保存下载信息(文件指针位置) 6+;2B<II  
private void write_nPos() iB3 +KR  
{ !-RpRRR[Co  
try{ %H}Y]D~R  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Mto~ /  
output.writeInt(nStartPos.length); ^1,Eo2yN  
for(int i=0;i<nStartPos.length;i++) `/JR}g{O  
{ wwcwYPeg  
// output.writeLong(nPos); b#;N!VX  
output.writeLong(fileSplitterFetch.nStartPos); \Tf{ui  
output.writeLong(fileSplitterFetch.nEndPos); UeQ9G  
} D'[P,v;Q  
output.close(); Df,VV+  
} Px7g\[]  
catch(IOException e){e.printStackTrace ();} .(dmuV9  
catch(Exception e){e.printStackTrace ();} /9+A97{  
} A Wh* <H  
lcT+$4zk.  
TnBGMI,g'  
//读取保存的下载信息(文件指针位置) a H|OA\<  
private void read_nPos() K@ sP~('  
{ _{`'{u  
try{ )]b@eGNGj  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); K# i*9sM  
int nCount = input.readInt(); NVA`t]gn  
nStartPos = new long[nCount]; ):fu   
nEndPos = new long[nCount]; {.D2ON  
for(int i=0;i<nStartPos.length;i++) 0"<;You  
{ %c&A h  
nStartPos = input.readLong(); )|h;J4V  
nEndPos = input.readLong(); aHPSnB&  
} uCP6;~Ns  
input.close(); ,6orB}w?z  
} LB*#  
catch(IOException e){e.printStackTrace ();} )47j8jL  
catch(Exception e){e.printStackTrace ();} =7]Q6h@X  
} gj egzKU  
Y\g90  
rI^~9Rz  
private void processErrorCode(int nErrorCode) aC8,Y$>?E`  
{ a,57`Ks+n<  
System.err.println("Error Code : " + nErrorCode); &^ 3~=$  
} enbN0  
(LT\ IJSM  
'q};L6  
//停止文件下载 >uchF8)e|  
public void siteStop() qtwT#z;Y  
{ zsMw5C  
bStop = true; Fy _<Ui  
for(int i=0;i<nStartPos.length;i++) p[@oF5M  
fileSplitterFetch.splitterStop(); _KM$u>B8  
O^R:_vb3I  
gKs/T'PW  
} Q 9gFTLQ  
} Gx h~  
//负责部分文件的抓取 4j@kMe;RjZ  
**FileSplitterFetch.java yS uLt@X  
*/ V:F+HMBk  
package NetFox; Ef_F#X0#  
L=$?q/=-  
93^(O8.  
import java.io.*; Hc&uE3=%sL  
import java.net.*; S QM(8*:X  
<(bCz>o|  
R%)2(\  
public class FileSplitterFetch extends Thread { RlslF9f  
@!&Jgg53G  
Y( V3P nH  
String sURL; //File URL LG Y!j_bD  
long nStartPos; //File Snippet Start Position Qw6KX#n  
long nEndPos; //File Snippet End Position p-i.ITRS  
int nThreadID; //Thread's ID |auX*hb9  
boolean bDownOver = false; //Downing is over I_zk'  
boolean bStop = false; //Stop identical {+/ .5  
FileAccessI fileAccessI = null; //File Access interface g]==!!^<D  
 $||ns@F+  
ER;lkF`RF  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException nqurY62Ip  
{ u>t|X}JH  
this.sURL = sURL; @`IXu$Wm(  
this.nStartPos = nStart; '!+ P{  
this.nEndPos = nEnd; 43{_Y]  
nThreadID = id; PQU3s$  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 w;yiX<t<  
} W? "2;](  
kyRh k\X  
S6Xb*6  
public void run() yUD_ w  
{ ~}7$uW0ol  
while(nStartPos < nEndPos && !bStop) }DDVGs[  
{ 2xL!PR-  
:_o] F  
_uO!N(k.  
try{ Q{.{#G  
URL url = new URL(sURL); -'O Q-5  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); >/!7i3Ow-  
httpConnection.setRequestProperty("User-Agent","NetFox"); 55>" R{q  
String sProperty = "bytes="+nStartPos+"-"; 6Q.{llO  
httpConnection.setRequestProperty("RANGE",sProperty); wO2V%v^bp  
Utility.log(sProperty); ,c,Xd  
RV0>-@/x  
-~v l+L  
InputStream input = httpConnection.getInputStream(); RjR&D?dc  
//logResponseHead(httpConnection); C@TN5?Z  
{[M0y*^64$  
[)Z 'N/;0  
byte[] b = new byte[1024]; '!j #X_;  
int nRead; .%x"t>]  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ?q d,>  
{ i\kTm?BQZ  
nStartPos += fileAccessI.write(b,0,nRead); QMXD9H0{  
//if(nThreadID == 1) O8K@&V p  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); )K>Eniou  
} 05l0B5'p  
c N02roQl  
B\=SAi  
Utility.log("Thread " + nThreadID + " is over!"); tr6jh=  
bDownOver = true; 3W7;f!  
//nPos = fileAccessI.write (b,0,nRead); [+g(  
} <mv7HKVg  
catch(Exception e){e.printStackTrace ();} ZQ,fm`y\  
} #dva0%-1  
} ~w Zl2I  
.-SDo"K.h  
g  ,/a6M  
//打印回应的头信息 I! h(`  
public void logResponseHead(HttpURLConnection con) 'O.+6`&  
{ Zdv.PGn  
for(int i=1;;i++) u-AWJc+F.  
{ V,>+G6e  
String header=con.getHeaderFieldKey(i); *'UhlFed  
if(header!=null) 0K=Qf69Y  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 5kGxhD  
Utility.log(header+" : "+con.getHeaderField(header)); W4)kkJ  
else 0Y2\n-`z  
break; g\ErJ+i  
} XIr{U5$<6  
} 2Pbe~[  
Q)x?B]b-  
vOos*&  
public void splitterStop() RL?u n}Qa  
{ u] F7 0C^~  
bStop = true; Ni+3b  
} I#"t'=9H  
zq,iLoY[R  
iP<k1#k  
} BQyvj\uJ  
j y7  
'M~BE\  
/* Ze-MAt  
**FileAccess.java NJn&>/vM  
*//文件访问(定位,写) aQ(`6DQv  
package NetFox; 7cIC&(h5  
import java.io.*; i LF^%!:X%  
 uY.=4l  
/SnynZ.q  
public class FileAccessI implements Serializable{ /h/6&R0l  
1|o$X  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 sCVI 2S!L  
RandomAccessFile oSavedFile; ;*y|8od B  
long nPos; <A)+|Y"^h6  
Vo #:CB=8  
jr9&.8%W:v  
public FileAccessI() throws IOException Y8)}P WMs  
{ _Ny8j~  
this("",0); =kd YN 5R  
} ,5/V@;i  
q.-y)C) ;  
-@rxiC:Q  
public FileAccessI(String sName,long nPos) throws IOException ?Q@L-H`  
{ `'u Umyg  
oSavedFile = new RandomAccessFile(sName,"rw"); }ppVR$7]0  
this.nPos = nPos; CV s8s  
oSavedFile.seek(nPos); #MUiL=  
} JxjP@nr  
#:$O=@@?M  
k]Zo-xh4  
public synchronized int write(byte[] b,int nStart,int nLen) #;d)?  
{ |</"N-#S  
int n = -1; 6G'<[gL j  
try{ 'g]hmE  
oSavedFile.write(b,nStart,nLen); IQT cYl  
n = nLen; 3=Z<wD s  
} {] O`g G  
catch(IOException e) ,:^ N[b   
{ x Y| yI>  
e.printStackTrace (); x ;Gz6|  
} IeVLn^?+:  
JL.5QzA  
NjbwGcH%\  
return n; t)ld<9)eB  
} !(Q l)C  
nB=0T`vQ  
NUMi])HkN  
} 3@G;'|z  
WE")xhV6  
)%s +?  
/* 9SY(EL  
**SiteInfoBean.java cqEHYJ;B  
*/ Xem 05%,  
package NetFox; Kh)F yV  
BBvZeG $Y  
L!gDFZr  
public class SiteInfoBean { jPnO@ H1  
z!:'V]  
y?>#t^  
private String sSiteURL; //Site's URL sMH#BCC  
private String sFilePath; //Saved File's Path p'&*r2_ram  
private String sFileName; //Saved File's Name aM$\#Cx  
private int nSplitter; //Count of Splited Downloading File |1"!k A  
6yI}1g  
k,rWa  
public SiteInfoBean() FSU<Y1|XM  
{//nSplitter的缺省值为5 H>.B99vp  
//default value of nSplitter is 5 >dk 9f}7-  
this("","","",5); ('t kZt%8  
} >!}`%pk(  
 QsOhz  
=E y`M#t;  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) n>P! u71  
{ M/{g(|{  
sSiteURL= sURL; A:eG5K}  
sFilePath = sPath; _R7 w?!t8  
sFileName = sName; t}Ss=0dJO  
this.nSplitter = nSpiltter; :mpiAs<%U"  
=OYQM<q  
W/r^ugDV  
} I]X  
cOkgoL" 4  
oEu>}JD  
public String getSSiteURL() h>wcT VF  
{ m"Qq{p|'  
return sSiteURL; ^mg*;8e Ga  
} [T`}yb@  
3sFeP &  
8Mu;U3cIW  
public void setSSiteURL(String value) U<47WfcW  
{ Pr+~Kif  
sSiteURL = value; C c*( {  
} HR60   
`5'2Hg+  
M$A#I51  
public String getSFilePath() &aPl`"j  
{ %jEY 3q  
return sFilePath; <tbZj=*O/o  
} i"HgvBHx  
9cd8=][  
K)S;:MLG=  
public void setSFilePath(String value) z856 nl  
{ >|3a 9S  
sFilePath = value; 0@)%h&mD  
} frN3S  
Km3&N  
DA"}A`HfI  
public String getSFileName() @T&t.|`  
{ @Z;1 g  
return sFileName; F Z!J  
} Y-p<qL|_  
+;q.Y?  
H9` f0(H  
public void setSFileName(String value) xd8 *<,Wj  
{ ~ y;y(4<  
sFileName = value; jxw_*^w"  
} R8&|+ya  
<y)E>Fl  
d TGA5c  
public int getNSplitter() 7zDiHac  
{ = .oHnMX2M  
return nSplitter; *Oo &}oAj  
} }nud  
k\N4@UK  
A+ 0,i  
public void setNSplitter(int nCount) E'c%d[:H,  
{ ;=jr0\|e  
nSplitter = nCount; 1f4 bt6[  
} ;/LD)$_  
} u+D[_yd^  
x*}bo))hb  
}!)F9r@\  
/* 8]< f$3.  
**Utility.java DjHp+TyT  
*/ 8)xt(~qF  
package NetFox; ~rv})4h  
$/_ qE  
0a2@b"l  
public class Utility { cDV ^8 R  
#Hu~}zy  
Ip?]K*sq  
public Utility() op7FZHs  
{ UG2w 1xqHw  
N4UM82N  
9z ?7{2C  
} K:5eek  
u&]vd /  
//线程睡眠 TJy4<rb  
public static void sleep(int nSecond) }$g mK  
{ *t9eZ!_f?  
try{ [!"XcFY:a  
Thread.sleep(nSecond); QH@>icAb  
} .px:e)iW  
catch(Exception e) onte&Ed\  
{ )`HA::  
e.printStackTrace (); Vhg1/EgUr  
} mBk5+KyT  
} 0ys~2Y!eH  
1 W'F3  
//日志 oq;'eM1,.  
public static void log(String sMsg) Ya Y8 `M{  
{ Bjj<\8 ^M  
System.err.println(sMsg); UUtbD&\  
} <I=$ry6 8  
cH D%{xlb  
Bw< rp-  
public static void log(int sMsg) Z1,gtl ?  
{ Hs0pW5oZ  
System.err.println(sMsg); >q7 %UK]&  
} 68t}w^=  
} {3edTu  
.~klG&>aV  
;D2E_!N dt  
/* B|o%_:]+E  
**TestMethod.java >a>fb|r  
*/ {0yu   
package NetFox; Xm_$ dZ  
B 0)]s<<  
`M@Ak2gcR+  
public class TestMethod { Y2T$BJJ  
kA#vByf`v  
6*XM7'n  
public TestMethod() LSd*| 3E}n  
{ ///xx/weblogic60b2_win.exe 8cVzFFQP  
try{ 5EeDHsvV9  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); [}o~PN:sT(  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); k%Vv?{g  
SiteFileFetch fileFetch = new SiteFileFetch(bean); g-)mav  
fileFetch.start(); n2ndjE$  
} 0SV\{]2  
catch(Exception e){e.printStackTrace ();} `  2%6V)s  
,x_Z JL  
K"{HseN{  
} J|QiH<  
%mI~ =^za  
*\XH+/]+  
public static void main(String[] args) RtV.d \  
{ rT7^-B*  
new TestMethod(); Un@\kAY  
} "{BqtU*.  
} xJ(:m<z  
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