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http断点续传简单实现(java)

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/* ^/@Z4(E  
**SiteFileFetch.java r&  
*/ .TZ0F xW  
package NetFox; qaJ$0,]H+  
import java.io.*; O&BNhuW2  
import java.net.*; )45~YDS;t  
cHo@F!{o=  
NZT2ni4  
public class SiteFileFetch extends Thread { WV5z~[  
#J=^CE  
4SRjF$Bsz  
SiteInfoBean siteInfoBean = null; //文件信息Bean eb1WTK@  
long[] nStartPos; //开始位置 _G3L+St  
long[] nEndPos; //结束位置 dpAj9CX(  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Qp>'V<%m-  
long nFileLength; //文件长度 1i=lJmr  
boolean bFirst = true; //是否第一次取文件 )(b, v/:  
boolean bStop = false; //停止标志 s/Ne,v  
File tmpFile; //文件下载的临时信息 QFekj@  
DataOutputStream output; //输出到文件的输出流 XBx&&  
pHKcKqB*13  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) <[.{aj]QV  
public SiteFileFetch(SiteInfoBean bean) throws IOException 3DjlX*  
{ 6=N!()s  
siteInfoBean = bean; hc7"0mVd{  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); E>LZw>^Y J  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ;ctPe[5  
if(tmpFile.exists ()) *<HA])D,  
{ eBT+|  
bFirst = false; `U4e]Qh/+  
read_nPos(); {7d(B1[1  
} 1fgO3N  
else i ZU 1w7Z  
{ C2e.RTxc  
nStartPos = new long[bean.getNSplitter()]; ZG(.Q:1  
nEndPos = new long[bean.getNSplitter()]; <TN+-)H6  
} lZ,w#sqbY  
7QSr C/e  
J|$UAOEDa  
8O^<#lh  
} g \.O5H9Od  
hW<TP'Zm*  
w-{a>ZU0  
public void run() =;L44.,g  
{ ,I|3.4z  
//获得文件长度 r+%$0eB1^  
//分割文件 C"SG':  
//实例FileSplitterFetch pu-X -j  
//启动FileSplitterFetch线程 o?,c#g  
//等待子线程返回 F TgqE@  
try{ cnw?3/J  
if(bFirst) x)+ q$FB  
{  " fXs!  
nFileLength = getFileSize(); y':JUwUN  
if(nFileLength == -1) E+Eug{+  
{ >DM^/EAG{  
System.err.println("File Length is not known!"); iQd,xr  
} t,w'w_C  
else if(nFileLength == -2) bU$f4J  
{ S =5br  
System.err.println("File is not access!"); 3g79/ w  
} %+pF4f8]  
else _-=yD@;[D  
{ J;DTh ]z?:  
for(int i=0;i<nStartPos.length;i++) ntr&? H  
{ to9X2^  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ;9MIapfUd(  
} tD^$}u6  
for(int i=0;i<nEndPos.length-1;i++) D[p_uDIz  
{ l=&\luNz  
nEndPos = nStartPos[i+1]; qtR/K=^i  
} )U|0vr8:  
nEndPos[nEndPos.length-1] = nFileLength; [AHoTlPZ  
} R4_BP5+  
} pQ,|l$^m  
W?H-Ng3E  
R$m?aIN  
//启动子线程 |S6L[Uo  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Au10]b  
for(int i=0;i<nStartPos.length;i++) n@=D,'cn  
{ XpH d"(*  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ]mR!-Fqj  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), mI> =S  
nStartPos,nEndPos,i); t) uS7y  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); /1BqC3]tL  
fileSplitterFetch.start(); )+ (GE  
} gmUX 2x(  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), vqhu%ZyP  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ooA%/  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", B<{Yj}..  
nEndPos = " + nFileLength); e;8nujdG"  
// fileSplitterFetch[nPos.length-1].start(); A$jf#,  
A.+Qa  
%#7 ]  
//等待子线程结束 "}Oj N\  
//int count = 0; y9U*E80q{  
//是否结束while循环 _aP 2gH  
boolean breakWhile = false; ~ugyUpY"  
Y3.^a5o  
jdf3XTw  
while(!bStop) G,X>f?  
{ 2cQG2N2*  
write_nPos(); *{!E`),FX  
Utility.sleep(500); e3.q8r  
breakWhile = true; 5~FXy{ZIH  
/B!Ik:c}  
Ba}<X;B}  
for(int i=0;i<nStartPos.length;i++) GdVrl[  
{ YH,u*.I^/  
if(!fileSplitterFetch.bDownOver) g1{2E<b 5  
{ =3;~7bYO  
breakWhile = false; $DeVXW  
break; v*JXrB&x  
} miUjpXt  
} "Z]z9(  
if(breakWhile) ~.$ca.Gf  
break; @[v4[yq-  
*J3Z.fq%:i  
%~I%*=o[  
//count++; 2l}H=DZV  
//if(count>4) Oj1B @QE  
// siteStop(); r7+Ytr  
} G%MdZg&i  
MlV3qM@  
B=)tq.Q7  
System.err.println("文件下载结束!"); ih=O#f|  
} )mu[ye"p  
catch(Exception e){e.printStackTrace ();} BIxjY!!"  
} m\f}?t  
y:YJv x6&4  
q0*d*j F0u  
//获得文件长度 CwaW>(`v  
public long getFileSize() u= Vt3%q  
{ o(stXa  
int nFileLength = -1; H~; s$!lG  
try{ (R]b'3,E$  
URL url = new URL(siteInfoBean.getSSiteURL()); n{"e8vQx  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); JN-W`2  
httpConnection.setRequestProperty("User-Agent","NetFox"); -ZH6*7!  
dO!B=/  
8SN4E  
int responseCode=httpConnection.getResponseCode(); !@T5](zV  
if(responseCode>=400) LMaY}m>  
{ MDauHtF,  
processErrorCode(responseCode); GhR%fxe  
return -2; //-2 represent access is error AP9>_0=  
} (5GjtFojY|  
" +A8w  
BnU3oP  
String sHeader; LAH.PcjPa  
.R _-$/ZP  
cH`ziZ<&m1  
for(int i=1;;i++) UIo jXR<  
{ 8Z>=sUMQ  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); MI,kKi  
//Utility.log(in.readLine()); (/jZ &4T  
sHeader=httpConnection.getHeaderFieldKey(i); ]6].l$%z#  
if(sHeader!=null) ;3&HZq6Z (  
{ 15_Px9  
if(sHeader.equals("Content-Length")) +:&|]$8<  
{ FvVM}l'  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Rg7~?b-  
break; [orS-H7^  
} fzr0dcNgM  
} "H|hN  
else lNx:_g:SrZ  
break; *n_7~ZX  
} |W*i'E   
} Vi>`g{\  
catch(IOException e){e.printStackTrace ();} evlz R/  
catch(Exception e){e.printStackTrace ();} uF\ ;m.  
XXy &1C  
]5+<Rqdbg  
Utility.log(nFileLength); R] " jr  
pwmH(94$0  
-Q" N;&'[&  
return nFileLength; i\C~]K~O!  
} =2/[n8pSsM  
Y))x'<T'Q  
?@H/;hB[|  
//保存下载信息(文件指针位置) y\mK?eR  
private void write_nPos() (3N;-   
{ LfX[(FP  
try{ >#|%y>g .o  
output = new DataOutputStream(new FileOutputStream(tmpFile)); P vW~EJ  
output.writeInt(nStartPos.length); cm`x;[e6l  
for(int i=0;i<nStartPos.length;i++) =j~Xrytn  
{ &6^QFqqW`-  
// output.writeLong(nPos); <nJ8%aY,  
output.writeLong(fileSplitterFetch.nStartPos); ]] 50c  
output.writeLong(fileSplitterFetch.nEndPos); '7UIzk|  
} XX'mM v  
output.close();  lx&;?QQ  
} \s_`ZEB  
catch(IOException e){e.printStackTrace ();} I5#zo,9  
catch(Exception e){e.printStackTrace ();} NU%<Ws=  
} O[^u<*fi{  
: \KJw  
$kxP{0u  
//读取保存的下载信息(文件指针位置) +J7xAyv_Oz  
private void read_nPos() }o7"2h ht  
{ CDT3&N1'R  
try{ 2py [P  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); DwI X\9  
int nCount = input.readInt(); KVp3 pUO  
nStartPos = new long[nCount]; Iz9b5  
nEndPos = new long[nCount]; z<,-:=BC"  
for(int i=0;i<nStartPos.length;i++) Qw.j  
{ uol EX+  
nStartPos = input.readLong(); R_B`dP<"~Y  
nEndPos = input.readLong(); ~c${?uf   
} {J]x81}*;  
input.close(); !c;BOCqa  
} M1J77LfS8  
catch(IOException e){e.printStackTrace ();} |`Iispn  
catch(Exception e){e.printStackTrace ();} .y>G/8_i  
} x"{WLZ   
CQ:38l\`gd  
Itv}TK eF  
private void processErrorCode(int nErrorCode) ':DLv{R  
{ %)sG 34  
System.err.println("Error Code : " + nErrorCode); O^sOv!!RH/  
} xMHu:,ND  
|6!L\/}M%  
tVhf1TH#  
//停止文件下载 $kd9^lj#[  
public void siteStop() Q3 yW#eD  
{ #L 9F\ <K  
bStop = true; ev9ltl{  
for(int i=0;i<nStartPos.length;i++) @<C<rB8R  
fileSplitterFetch.splitterStop(); p #Y2v  
fm$)?E_Rp  
}S6"$R  
} &z?:s  
}  _!E)a  
//负责部分文件的抓取 /Bp5^(s  
**FileSplitterFetch.java `R,g_{M j  
*/ #GOL%2X  
package NetFox; !Hx[ `3  
L<Q>:U.@\  
)GR4U8<>g  
import java.io.*; v 6KRE3:V  
import java.net.*; L<0eIw  
s|IC;C|  
6 B*,Mu4A  
public class FileSplitterFetch extends Thread { v&Oc,W  
Z^O_7I<5E  
wOF";0EN  
String sURL; //File URL rLp (}^  
long nStartPos; //File Snippet Start Position z65Q"A  
long nEndPos; //File Snippet End Position vY2^*3\<D  
int nThreadID; //Thread's ID m.w.h^f$&  
boolean bDownOver = false; //Downing is over U$7]*#@&  
boolean bStop = false; //Stop identical ?V' zG&n@  
FileAccessI fileAccessI = null; //File Access interface kR65{h"gZT  
:4/37R(~l8  
}N0v_Nas;v  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 1)hO!%  
{ tPaNhm[-q7  
this.sURL = sURL; {3eg4j.Z  
this.nStartPos = nStart; R?iC"s!  
this.nEndPos = nEnd; T.pc3+B8N  
nThreadID = id; [(*?  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Y>Fh<"A|$  
} 2k M;7:  
Eal*){"<,?  
\^x`GsVy  
public void run() IIO-Jr  
{ RiiwsnjC  
while(nStartPos < nEndPos && !bStop) wf2v9.;X:<  
{ &NH[b1NMr  
u#nM_UJe  
Dy|)u1?  
try{ 'f-8P  
URL url = new URL(sURL); uYCWsw/  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); x&*2R#Ai  
httpConnection.setRequestProperty("User-Agent","NetFox"); og`K! d~  
String sProperty = "bytes="+nStartPos+"-"; d[`vd^hI  
httpConnection.setRequestProperty("RANGE",sProperty); +'{d^-( (  
Utility.log(sProperty); GUC.t7!  
v \dP  
{'z(  
InputStream input = httpConnection.getInputStream(); y&6 pc   
//logResponseHead(httpConnection); (D2N_l(`<  
.O6(QI*  
%/w%A:y#&  
byte[] b = new byte[1024]; HpIW H*  
int nRead; =fK6P6'B  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) v,d'SR.  
{ /wU4^8Hz  
nStartPos += fileAccessI.write(b,0,nRead); M`p[ Zq  
//if(nThreadID == 1)  w\y)  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); "Pa  y2  
} b=XXp`h~a  
q aG8:  
Y|cj&<o  
Utility.log("Thread " + nThreadID + " is over!"); gN .n _!  
bDownOver = true; c' Q4Fzj0'  
//nPos = fileAccessI.write (b,0,nRead); uU/'oZ?  
} E7  P'}  
catch(Exception e){e.printStackTrace ();} %r]V:d+  
} J*4T| #0  
} A,4Z{f83  
'$5Qdaj  
`J %35  
//打印回应的头信息 AmB*4p5b  
public void logResponseHead(HttpURLConnection con) WSbD."p<  
{ c7A]\1 ~  
for(int i=1;;i++) 9QHV%%  
{ N#GMvU#R  
String header=con.getHeaderFieldKey(i); 5#~E[dr  
if(header!=null) <-"[9 w  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); w+gPU1|(r  
Utility.log(header+" : "+con.getHeaderField(header)); ={\9-JJhE  
else 4 }NCdGD  
break; Qrw:Bva)  
} b<j*;n.  
} 5M\bH'1  
v]y=+* A  
y wmC>`0p  
public void splitterStop() <&l@ ):a  
{ Y_/w}HB  
bStop = true; uZa)N-=b2  
} h-6x! 6pm  
v+C%t!dx  
0t%`jY~%  
} upiYo(sN.  
3;F up4!4}  
C(n_*8{  
/* cUr5x8<W).  
**FileAccess.java _ ($U\FW  
*//文件访问(定位,写) 7{p6&xXx  
package NetFox; NIG* }[}P  
import java.io.*; L[tq@[(IJ  
Dlg9PyQ  
('+C $  
public class FileAccessI implements Serializable{ Q2"K!u]  
S3^(L   
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 |LirjC4  
RandomAccessFile oSavedFile; <=%=,Yk  
long nPos;  ?%*p!m  
:kvQ3E0  
V^< Zs//7  
public FileAccessI() throws IOException pYh\l.@qf  
{ y>0Gmr  
this("",0); Jk57| )/  
} T@d4NF#  
O@a7MzJ  
O+t'E9Fa  
public FileAccessI(String sName,long nPos) throws IOException {Rq5=/b  
{ G%>M@nYUE  
oSavedFile = new RandomAccessFile(sName,"rw"); |xrnLdng0R  
this.nPos = nPos; uOPLJ?%  
oSavedFile.seek(nPos); 8aTo TA7JA  
} \f'=  
kV4,45r  
"] ]aF1  
public synchronized int write(byte[] b,int nStart,int nLen) ~0rvrDDg  
{ @4Lol2  
int n = -1; ,Bl_6ZaL  
try{ ;0-R"c)-  
oSavedFile.write(b,nStart,nLen); hbm #H7Y  
n = nLen; nnCz!:9p  
} iUlSRfrC$#  
catch(IOException e) )H+p6<  
{ W4=A.2[q  
e.printStackTrace (); JhvT+"~  
}  tk+4noA  
Wa9yyc  
W!JEl|]  
return n; JvYs6u  
} gnlU  
;&XC*R+  
i<*W,D6  
} meZZQ:eSl  
c9Q_Qr0'  
.gY=<bG/fA  
/* 2:&L|;  
**SiteInfoBean.java xXCsJ9]  
*/ z\>ZgRi~n  
package NetFox; Gm=e;X;r  
^M+aQg%  
0P;\ :-&p  
public class SiteInfoBean { )B"E+Q'h{7  
Se>v|6  
h]&o)%{4  
private String sSiteURL; //Site's URL _7 ^:1i~:.  
private String sFilePath; //Saved File's Path <(l`zLf4p  
private String sFileName; //Saved File's Name $`<-;kI  
private int nSplitter; //Count of Splited Downloading File !*o{xq   
{ }P~nP  
w`[`:H_z  
public SiteInfoBean() 5 Q,j+  
{//nSplitter的缺省值为5 9>;CvR  
//default value of nSplitter is 5 K+`deH_d  
this("","","",5); } wx(P3BHD  
} Mg&<W#$K  
DS;.)P"  
cyB2=,  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) BzTzIo5  
{ @>`qfy?  
sSiteURL= sURL; .M0pb^M  
sFilePath = sPath; bSa]={}L(  
sFileName = sName; <tdsUh:?&  
this.nSplitter = nSpiltter; l0eh}d  
k=9k4l  
2yVQqwQ m  
} (V0KmNCW`  
t:n$9WB)  
,fvhP $n  
public String getSSiteURL() s1p<F,  
{ n>xuef   
return sSiteURL; iB+ _+A  
} @>+`1C  
5m\)82s  
5>h/LE]"  
public void setSSiteURL(String value) "8E=*2fcw  
{ =.qPjp_Qd  
sSiteURL = value; _o==  
} =]o2{d  
zm#%]p80f  
ld#YXJ;P.k  
public String getSFilePath() Lm+E?Ca  
{ #wJ^:r-c`  
return sFilePath; E5Lq-   
} er<_;"`1  
YTg8Zg-Z  
A-u!{F  
public void setSFilePath(String value) g\H~Y@'{  
{ 2Hk21y\  
sFilePath = value; $F6GCM3Cx  
} [d=BN ,?  
|}@teN^J*U  
bVr`a*EM  
public String getSFileName() lU.aDmy<  
{ |(uo@-U  
return sFileName; V-18~+F~"a  
} n!U1cB{  
6n H'NNS:J  
w I[Hoi V  
public void setSFileName(String value) Nhtc^DX  
{ WLH ;{  
sFileName = value; &:~9'-O  
} /*G bl  
z6fY_LL  
yF-`f _  
public int getNSplitter() 3dgPP@7d$  
{  KON^  
return nSplitter; Rb0{W]opt+  
} 1";s #Jq  
<ka zV<"  
xu >grj  
public void setNSplitter(int nCount) rr2^sQ;_  
{ Q1!+wC   
nSplitter = nCount; L;=LAQ6[  
} 4^!%>V"d/  
} |#Q0UM|'Q  
10tTV3`IM  
a[=ub256S  
/* Wr8}=\/  
**Utility.java dwb^z+   
*/ T*k}E  
package NetFox; VRg y  
$<L@B|}F)  
Yw\lNhoPS  
public class Utility { /1eeNbd  
6 kD.  
NleMZ  
public Utility() o bGvd6\  
{ $&sV.fGu  
{ &J OO  
ITD&w g  
} *P?Rucg  
c`oW-K{  
//线程睡眠 +y\o^w4sT  
public static void sleep(int nSecond) C%#u2C2  
{ W)L*zVj~  
try{ pz"}o#R"x  
Thread.sleep(nSecond); - x;xQ  
} 2`Ihrz6  
catch(Exception e) g O/\Yi  
{ QE721y   
e.printStackTrace (); uW4.Q_O!H  
} 0XI6gPo%  
} 9[[$5t`8  
UD Pn4q  
//日志 h r6?9RJY  
public static void log(String sMsg) (UZ].+)s  
{ Sx1OY0)s  
System.err.println(sMsg); Y4[oa?G  
} k h6n(B\  
&,* ILz  
@0%[4  
public static void log(int sMsg) *DQa6,b  
{ /)sP<WPQ 6  
System.err.println(sMsg); F6_e n z  
} '_ys4hz}  
} H`jnChD:M'  
B/Ltb^a  
i;\n\p1  
/* A.(e=;0bu  
**TestMethod.java p[}~Z|(  
*/ Ao\Im(?  
package NetFox; 8 EU/}Ym  
,x?Jrcx~'C  
< Yc)F.:  
public class TestMethod { @QE&D+NS  
VFKFO9  
D58RHgY[  
public TestMethod() 6_K7!?YG7  
{ ///xx/weblogic60b2_win.exe AB<%GzW0(  
try{ yi2F#o 'K  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); U#{(*)qr  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); WwUHHm<v  
SiteFileFetch fileFetch = new SiteFileFetch(bean); u1>WG?/`  
fileFetch.start(); b&'YW*W  
} #q5tG\gnM  
catch(Exception e){e.printStackTrace ();} nd w&F'.r  
fr}.#~{5Y  
o ^ 08<  
} 2s}G6'xE]P  
MjbgAH-  
h)s&Nqg1B  
public static void main(String[] args) w%(D4ldp   
{ 9U3.=J  
new TestMethod(); <@c@`K  
} g!Ui|]BI9  
} # hw;aQ  
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