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http断点续传简单实现(java)

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/* Z'j[N4%BK  
**SiteFileFetch.java j`"!G*Vh  
*/ qPD(D{,f$  
package NetFox; qbD 7\%  
import java.io.*; EpNN!s=Q  
import java.net.*; \/<VJB uV  
\eNB L[  
M;Pry 3J  
public class SiteFileFetch extends Thread { >W8"Ar  
1P[x.t#  
8U(o@1PT  
SiteInfoBean siteInfoBean = null; //文件信息Bean [tof+0Y6  
long[] nStartPos; //开始位置 H7.l)'  
long[] nEndPos; //结束位置 O^=+"O]  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 x55W"q7  
long nFileLength; //文件长度 ?RS:I%bL  
boolean bFirst = true; //是否第一次取文件 te2vv]W1  
boolean bStop = false; //停止标志 KcpYHWCa.  
File tmpFile; //文件下载的临时信息 \u{4=-C.  
DataOutputStream output; //输出到文件的输出流 u>.a;BO  
G 3,v'D5  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) @L~erg>8=  
public SiteFileFetch(SiteInfoBean bean) throws IOException ]"HaE-`%  
{ !CX WoM  
siteInfoBean = bean; *!$Z5Im  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); a-E}3a  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); -$o0P'Vx  
if(tmpFile.exists ()) QEf@wv;T  
{ -*4*hHmb  
bFirst = false; 3.?be.cq  
read_nPos(); ?R#$ c]  
} nOL.%  
else Z3hZy&_I  
{ _3@5@1[s  
nStartPos = new long[bean.getNSplitter()]; x1#>"z7  
nEndPos = new long[bean.getNSplitter()]; 7~QI4'e  
} Rr %x;-  
O 1z0dHa  
=xIZJ8e  
z/xPI)R[  
} p>+9pxx~U  
o zn&>k  
-grf7w^  
public void run() 1J"9Y81   
{ g ass Od  
//获得文件长度 5[SwF& zZ  
//分割文件 S Dil\x  
//实例FileSplitterFetch 9/{zS3h3  
//启动FileSplitterFetch线程 8!Wh`n<  
//等待子线程返回 ').) 0;  
try{ \ m~?yq8H  
if(bFirst) uStAZ ~b\  
{ Dho6N]86r  
nFileLength = getFileSize(); ]$Z:^" JS3  
if(nFileLength == -1) s2G9}i{  
{ Y /_CPY  
System.err.println("File Length is not known!"); LZe)_9$  
} 3r kcIVO  
else if(nFileLength == -2) `"&Nw,C  
{ A_oZSUrR  
System.err.println("File is not access!"); WM ?a1j  
} Pn OWQ8=  
else hk4t #Km  
{ {owuYVm  
for(int i=0;i<nStartPos.length;i++) ( ~5 M{Xh  
{ r)'vn[A  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); \OVtvJV]  
} `R8&(kQ  
for(int i=0;i<nEndPos.length-1;i++) IB[$~sGe  
{ Pn">fWRCx  
nEndPos = nStartPos[i+1]; \6SjJ]o>  
} )Q =>7%ZA  
nEndPos[nEndPos.length-1] = nFileLength; Yu3S3aRE  
} H"l4b4)N\  
}  rvd $4l^  
950N\Y @u  
%|(c?`2|  
//启动子线程   < v]  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; p 4> ThpX  
for(int i=0;i<nStartPos.length;i++) "g ^i%  
{ zk8 )!Af  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), w7?fJ")  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), $C\ETQ@  
nStartPos,nEndPos,i); P+hcj p*  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ~/`/r%1/J  
fileSplitterFetch.start(); &su'znLV  
} mfQ#n!{ZH  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), vNGE]+QX  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ~#*C,4m  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", !|&|%x6@  
nEndPos = " + nFileLength); ^)gyKl:E'  
// fileSplitterFetch[nPos.length-1].start(); 8mreHa  
o2ggHZe/=@  
Bxm,?=h  
//等待子线程结束 (CxA5u1|l  
//int count = 0; :uo1QavO@,  
//是否结束while循环 $gBQ5Wd  
boolean breakWhile = false; R}=5:)%w  
?ZRF]\dP]  
p5fr}#en  
while(!bStop) lWId 0eNS  
{ eA4:]A"  
write_nPos(); +Ua|0>?  
Utility.sleep(500); F$?Ab\#B  
breakWhile = true; vAUt~ X"  
13!@L bC  
}~I!'J#)  
for(int i=0;i<nStartPos.length;i++)  lln"c  
{ z5fE<=<X_W  
if(!fileSplitterFetch.bDownOver) njy2pDC@  
{ :jl*Y-mM  
breakWhile = false; C:J;'[,S  
break; XA2Ld  
} NZq-%bE  
} ccuGM WG*  
if(breakWhile) .c"nDCFVR  
break; QF"7.~~2  
9b+jT{Tg  
]^~}/@  
//count++; 2nB99L{6  
//if(count>4) FbE/x$;~O  
// siteStop(); u-TT;k'  
} JnBUW"  
SN{+ Pk  
&$~fz":1!  
System.err.println("文件下载结束!"); C 5.3[  
} lhN@ ,q  
catch(Exception e){e.printStackTrace ();} V*4Z.3/E5  
} 3^o(\=-JX  
k6Kc{kY  
fc9;ZX7  
//获得文件长度 8v"rM >[  
public long getFileSize() ebk>e*  
{ EU?qLj':  
int nFileLength = -1; {[o NUzcd  
try{ qk(Eyp  
URL url = new URL(siteInfoBean.getSSiteURL()); \3 SY2g8+  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ?gE=hh  
httpConnection.setRequestProperty("User-Agent","NetFox"); RPz[3y  
D|LO!,=b  
OM\J4"YV$  
int responseCode=httpConnection.getResponseCode(); b{A[\ "  
if(responseCode>=400) J6Z[c*W  
{ \]tBwa  
processErrorCode(responseCode); @k?vbq  
return -2; //-2 represent access is error r6m^~Wq!}  
} } e[ E  
x%B_v^^^  
v"bWVc~H  
String sHeader; T`bYidA  
a('0l2e<u9  
&GP(yj]  
for(int i=1;;i++) iE~!?N|a3  
{ -N45ni87  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); w+br)  
//Utility.log(in.readLine()); DB'0  
sHeader=httpConnection.getHeaderFieldKey(i); E`IXBI  
if(sHeader!=null) KUI{Z I  
{ v ccH(T  
if(sHeader.equals("Content-Length")) t%=7v)IOE  
{ E=sh^Q(A  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); TjW!-s?S  
break; OdzeHpH3g  
} Cy~IB [  
} |p|Zv H  
else s.2f'i+  
break; 2@|`Ugjptl  
} ?XBdBR_"^  
} -/Q5?0z  
catch(IOException e){e.printStackTrace ();} pHeG{<^  
catch(Exception e){e.printStackTrace ();} VdHT3r  
iGW|j>N  
Y <6|z3  
Utility.log(nFileLength); R|st<P  
 U4!bW  
#"gt&t9Q  
return nFileLength; "<CM 'R  
} }. &nEi`  
;2f=d_/x  
mxv ?PP  
//保存下载信息(文件指针位置) }je<^]a  
private void write_nPos() jl,gqMn"V  
{ / ;`H )  
try{ DzZF*ylQ5P  
output = new DataOutputStream(new FileOutputStream(tmpFile)); uF7vba$  
output.writeInt(nStartPos.length); &`^(dO9  
for(int i=0;i<nStartPos.length;i++) @.t +  
{ BlVHP8/b  
// output.writeLong(nPos); o=m5AUe?J  
output.writeLong(fileSplitterFetch.nStartPos); 7)rQf{q7  
output.writeLong(fileSplitterFetch.nEndPos); W5R/Ub@g  
} ng1E'c]0@  
output.close(); k<9,Ypa  
} "-4|HA  
catch(IOException e){e.printStackTrace ();} tr0b#4  
catch(Exception e){e.printStackTrace ();} H,7='n7"  
} %BI8m|6  
;d?BVe?  
?%O>]s  
//读取保存的下载信息(文件指针位置) -)V0D,r$[  
private void read_nPos() BZeEZ2"  
{ Y+-yIMt$r  
try{ o|xf2k  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); S^QEctXU  
int nCount = input.readInt(); q\fbrv%I4  
nStartPos = new long[nCount]; JX59n%$@  
nEndPos = new long[nCount]; K9<8FSn  
for(int i=0;i<nStartPos.length;i++) pS?D~0Nb  
{ (XZ[-M7  
nStartPos = input.readLong(); 7e<=(\(yl  
nEndPos = input.readLong(); *p{p.%Qs:  
} odP<S.  
input.close(); o@Ye_aM~?Y  
} TegdB|y7O  
catch(IOException e){e.printStackTrace ();} Jf^3nBZ  
catch(Exception e){e.printStackTrace ();} )."ob=m  
} Pf;OYWST  
nW=6nCyvo  
x;mw?B[  
private void processErrorCode(int nErrorCode) xdSMYH{2A  
{ z g7Q`  
System.err.println("Error Code : " + nErrorCode); YD4I2'E  
} a*M|_&MH*  
%['NPs%B  
(hc!!:N~q  
//停止文件下载 N_%@_$3G]  
public void siteStop() '(]Wtx%9"  
{ Wv4$Lgr  
bStop = true; NEBhVh  
for(int i=0;i<nStartPos.length;i++) Qf:e;1F!  
fileSplitterFetch.splitterStop();  ][ $UN  
Y>$5j}K  
e~vO   
} +)c<s3OCE  
} q;K]NP-_p  
//负责部分文件的抓取 (B#FLoK  
**FileSplitterFetch.java R @\fqNq  
*/ dle\}Sy=  
package NetFox; gwaSgV$z  
]OpGD5jZ  
KloX.y)q  
import java.io.*; wSR|uh  
import java.net.*; 49 FP&NgK  
igu1s}F  
{ 4+/0\  
public class FileSplitterFetch extends Thread { '/GB8L  
tQ }GTqk  
Ana[>wSZO@  
String sURL; //File URL -@AhJY.  
long nStartPos; //File Snippet Start Position F}Zg3 #  
long nEndPos; //File Snippet End Position =Uk #7U"P  
int nThreadID; //Thread's ID <$A,|m  
boolean bDownOver = false; //Downing is over >MYxj}I4{z  
boolean bStop = false; //Stop identical ^B.Z3Y  
FileAccessI fileAccessI = null; //File Access interface FK BRJ5O  
p\zqZ=s  
FBE|pG7  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException +Xg:*b9So  
{ 7FwtBO  
this.sURL = sURL; ".jO2GO^  
this.nStartPos = nStart; Sct  
this.nEndPos = nEnd; WsTIdr36x  
nThreadID = id; F=F84 _+K  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ww|fqx?  
} ^!tX+`,6^  
9Qyc!s`  
N[@~q~v  
public void run() L|[i<s;  
{ Od.@G~  
while(nStartPos < nEndPos && !bStop) 5Sl"1HL  
{ -zECxHj x  
P$'PB*5d|  
GW {tZaB  
try{ CC^D4]ug  
URL url = new URL(sURL); MJX ny4n  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); .#y#u={{l  
httpConnection.setRequestProperty("User-Agent","NetFox"); C b'|  
String sProperty = "bytes="+nStartPos+"-"; \BBs;z[/  
httpConnection.setRequestProperty("RANGE",sProperty); 05F/&+V  
Utility.log(sProperty); c:Czu  
 W2` 3 p  
B1X&O d  
InputStream input = httpConnection.getInputStream(); ]MCH]/  
//logResponseHead(httpConnection); U<Oc&S{]*  
Vg62HZ |  
J_F\cM   
byte[] b = new byte[1024]; E+y_te^+b  
int nRead; {GtX:v#  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) j*>]HNo&  
{ +.djC3^:  
nStartPos += fileAccessI.write(b,0,nRead); x)80:A}  
//if(nThreadID == 1) .i\ FK@2  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ]Mq-67  
} H[w';u[%  
/ 0$ !.  
'&Ur(axs  
Utility.log("Thread " + nThreadID + " is over!"); `U0XvWPr[  
bDownOver = true; tnpEfi-  
//nPos = fileAccessI.write (b,0,nRead); IV~)BW leT  
} Z6B$\Q5Od  
catch(Exception e){e.printStackTrace ();} R1JD{  
} ~v&Q\>'  
} +PPQ"#1pS  
}^I36$\  
o4: e1  
//打印回应的头信息 @Mg&T$  
public void logResponseHead(HttpURLConnection con) ](I||JJa9f  
{ G{?`4=K  
for(int i=1;;i++) 0%xb):Ctw  
{ 9T;>gm  
String header=con.getHeaderFieldKey(i); dLqBu~*  
if(header!=null) @oY+b!L  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); bV:<%l]  
Utility.log(header+" : "+con.getHeaderField(header)); Jd `Qa+  
else  U :x;4  
break; NxJnU<g-  
} h_-4Q"fb(  
} wv3*o10_w8  
^vm6JWwN0B  
"E<+idoz  
public void splitterStop() v2gk1a &  
{ !4v>|tq!  
bStop = true; Ot.v%D`e 5  
} g mWwlkf9  
= y^5PjN  
o(}%b8 K  
} C D6N8n]  
RKrNmD*rk*  
zWPX  
/* DhxS@/  
**FileAccess.java `JV(ae0  
*//文件访问(定位,写) FzOWM7+\  
package NetFox; ;E{jn4B'  
import java.io.*; }72\Aw5  
d&G]k!|\  
o]V.6Ge-  
public class FileAccessI implements Serializable{ &g}P)x r  
{Zw;<1{E  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 z 3[J sE%  
RandomAccessFile oSavedFile; 1tO96t^d%  
long nPos; v? 8i;[  
P cbhylKd  
+*W lj8  
public FileAccessI() throws IOException lA4-ZQ2Zp[  
{ .~ uKr^%  
this("",0); (z;lNl(*C  
} 1mHS -oI9J  
}.s%J\ckx  
Q(A$ >A  
public FileAccessI(String sName,long nPos) throws IOException Dl~(NLM  
{ `3? HQ2n  
oSavedFile = new RandomAccessFile(sName,"rw"); gdSqG2/&  
this.nPos = nPos; >+<b_q|P  
oSavedFile.seek(nPos); ^?]-Q*w3Qs  
} a/s5Oit2'X  
&kvmLOI  
vx7=I\1  
public synchronized int write(byte[] b,int nStart,int nLen) ic}TiTK  
{ o6w8Y/VPu  
int n = -1; zrSYLG  
try{ L[:A Ue  
oSavedFile.write(b,nStart,nLen); [&P @0F n  
n = nLen; va QsG6q[  
} rF}Q(<Y86  
catch(IOException e) U<F|A!Fg  
{ 6.tA$#6HP  
e.printStackTrace (); gT=pO`a  
} )sQ/$gJ  
RIUJX{?  
NKEmY-f;  
return n; 4V{&[ Z  
} "{+2Q  
y(iq  
->OVNmCB`+  
} nT01B1/<]  
%hmRh~/&  
&=S:I!9;;  
/* k(7Q\JKE  
**SiteInfoBean.java H_XspiB@  
*/ /? d)01  
package NetFox; g/68& M  
gREk,4DAv  
'Qg!ww7O  
public class SiteInfoBean { g - !  
*@^@7`W  
K:XP;#OsP  
private String sSiteURL; //Site's URL [;yH.wn#5  
private String sFilePath; //Saved File's Path V=fh;p  
private String sFileName; //Saved File's Name AB3OG*C9  
private int nSplitter; //Count of Splited Downloading File 8kcMgCO  
yaG:}=.3  
,?jc0L.'r]  
public SiteInfoBean() B1FJAKI);  
{//nSplitter的缺省值为5 +-),E.  
//default value of nSplitter is 5 Odw'Ua  
this("","","",5); Wj!+ E{y<r  
} I YtiX  
F#L1~\7  
%2b^t*CQ  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) )l! /7WKY  
{ 1_!?wMo:f  
sSiteURL= sURL; fD(r/~Vu  
sFilePath = sPath; x%k@&d;z  
sFileName = sName; Vh;|qF 9  
this.nSplitter = nSpiltter; vm;%713#1  
}%PK %/ zI  
o_b3G  
} rZ n@i  
F_-xp1|  
mT-[I<  
public String getSSiteURL() $aU.M3  
{ JvvN>bg  
return sSiteURL; 7BINqVS&  
} F7j/Zuj  
tw.GBR  
(_@]-   
public void setSSiteURL(String value) cK\ u  
{ |,=^P` #%  
sSiteURL = value; LjGZp"&{  
} 1,h:|  
X=1o$:7  
MCEHv}W  
public String getSFilePath() =#pYd~  
{ PCL ;Z  
return sFilePath; $v#`2S(7  
} &L+.5i  
G!B:>P|\l  
m44a HBwId  
public void setSFilePath(String value) ^$% Sg//  
{ (y6}xOa(  
sFilePath = value; ^ Lc\{,m  
} _[E+D0A  
1|w@f&W"  
k]$oir  
public String getSFileName() + a nsN~3  
{ =+mb@#="m  
return sFileName; } )L z%Z  
} 7$g$p&,VX  
w1-P6cf  
/i27F2NQm  
public void setSFileName(String value) Nc4;2~XwRp  
{ J]Z~.f="  
sFileName = value; &)+H''JY  
} JN9>nC!Zy_  
[mjie1j/<  
#| ,cy,v4  
public int getNSplitter() |LbAW /9a  
{ vC@^B)5gb  
return nSplitter; *{+{h;p  
} #O;JV}y  
rq!*unJ  
a9p:k ]{  
public void setNSplitter(int nCount) ! #! MTk  
{ 6YNL4HE?  
nSplitter = nCount; qF `6l(  
} YI7M%B9Lj  
} Mth:V45G|  
ti%RE:*  
_ h#I}uJ~  
/* TvDC4tm-:  
**Utility.java kD;pj3o&"2  
*/ `vOL3`P  
package NetFox; sfr+W-7kx  
M+VWAh#uD  
>L!c} Ku  
public class Utility { 7XyCl&Dc:  
pk.\IKlG]  
^5Lk}<utw  
public Utility() n6WKk+  
{ 8aWEl%  
h ':ZF  
EmcLW74  
} !YjxCx  
7CuZ7!>$  
//线程睡眠 ZGR5"el!  
public static void sleep(int nSecond) f4Y)GO<R]  
{ 4%ooJi|)  
try{ xR3$sA2  
Thread.sleep(nSecond); Ws`ndR  
} /qIl)+M  
catch(Exception e) rq8 d}wj  
{ YVDFcN9v  
e.printStackTrace (); >god++,o  
} ]nB|8k=J  
} \298SH(!7  
; iia?f1  
//日志 /o m++DxV  
public static void log(String sMsg) RhHm[aN  
{ U3V5Jo r#  
System.err.println(sMsg); 1F`jptVQ\G  
} Px=@Tw N,  
6^'BTd  
qJdlZW<  
public static void log(int sMsg) )'U0n`=  
{ A/'po_'uy  
System.err.println(sMsg); ySmbX  
} .nrllVG%`  
} v}Ju2}IK  
18Y#=uH}  
@0@ZlH wM  
/* sg^|dS{3D  
**TestMethod.java Wvr{l  
*/ s b;q)Rh  
package NetFox; ?![[la+f  
P7.bn  
&R%'s1]o  
public class TestMethod { W/ Q*NB  
OA[e}Vn  
] c7X~y  
public TestMethod() g5@g_~ g  
{ ///xx/weblogic60b2_win.exe vW=L{8zu  
try{ 2Ckx.m&  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); H TOr  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); &2`p#riAS  
SiteFileFetch fileFetch = new SiteFileFetch(bean); rtj`FH??11  
fileFetch.start(); \]u;NbC]  
} (*9.GyK  
catch(Exception e){e.printStackTrace ();} _2!8,MX  
VWE>w|'  
;[Mvk6^'R  
} h0rPMd(K  
8 XB[CbO  
^'V :T Y  
public static void main(String[] args) T[bCY 6  
{ ~_D.&-xUF  
new TestMethod(); ?@.v*'qR  
} Jo\P,-\(  
} h<Aq|*  
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