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http断点续传简单实现(java)

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/* &~Hx!]uc  
**SiteFileFetch.java }Fq~!D Ee  
*/ ^-^ii 3G`  
package NetFox; 634OH*6  
import java.io.*; te[#FF3{  
import java.net.*; m;4qs#qCg?  
n^lr7(!6  
luWr.<1  
public class SiteFileFetch extends Thread { urbSprdF  
TCWt3\  
>%\&tS'  
SiteInfoBean siteInfoBean = null; //文件信息Bean M*gbA5  
long[] nStartPos; //开始位置 drwD3jx0xv  
long[] nEndPos; //结束位置 6*&$ha}X  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 F tS"vJ\  
long nFileLength; //文件长度 73p7]Uo  
boolean bFirst = true; //是否第一次取文件 ''Y'ZsQ;  
boolean bStop = false; //停止标志 `R!%k]$  
File tmpFile; //文件下载的临时信息 L*#W?WMM v  
DataOutputStream output; //输出到文件的输出流 *)Us   
8a8CY,n{  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) o#K*-jOfiH  
public SiteFileFetch(SiteInfoBean bean) throws IOException \[9^,Q P  
{ # 4&t09  
siteInfoBean = bean; 14pyHMOR  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ~K/_51O'  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); J?9n4 u  
if(tmpFile.exists ()) (Q?@LzCjy  
{ y*#YIS56I  
bFirst = false; ;F;Vm$  
read_nPos(); =]fOQN`  
} $TX]*hNn  
else mHyT1e  
{ >bFrJz}  
nStartPos = new long[bean.getNSplitter()]; 9;7|MPbR  
nEndPos = new long[bean.getNSplitter()]; (V x2*Aw]  
} OLZs}N+;]  
h(K}N5`  
ucYweXsO3  
5 W!#,jz  
} & [z<p  
WYN0,rv1:+  
nw-%!}Ot"  
public void run() tMiy`CPh  
{  3 GL,=q  
//获得文件长度 3y%,f|ju  
//分割文件 LC, 6hpmh  
//实例FileSplitterFetch  Al1}Ir   
//启动FileSplitterFetch线程 tbXl5x0  
//等待子线程返回 _)S['[  
try{ ()Q#@?c~  
if(bFirst) %"Ia]0  
{ 6z5wFzJv?q  
nFileLength = getFileSize(); F};T<#  
if(nFileLength == -1) P84= .* >  
{ %-KgR  
System.err.println("File Length is not known!"); w `nm}4M  
} T'ei>]y]  
else if(nFileLength == -2) &n'@L9v81  
{ IhHKRb[  
System.err.println("File is not access!"); RT. %\)))  
} Alk+MwjR  
else `t"7[Zk  
{ f>iDq C4  
for(int i=0;i<nStartPos.length;i++) cE^Ljk  
{ Vq599M:)V  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); l* z "wA-  
} USg,=YM  
for(int i=0;i<nEndPos.length-1;i++) 9H/C(Vo  
{ GOsOFs"I  
nEndPos = nStartPos[i+1]; #p<(2wN  
} 2f0mr?l)N  
nEndPos[nEndPos.length-1] = nFileLength; =pBr_pGz=  
} A*~BkvPr  
} j+PLtE   
PA*1]i#2M=  
T/PmT:Qg `  
//启动子线程 |'``pq/}_  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; t*J?#r  
for(int i=0;i<nStartPos.length;i++) !>#gm7  
{ ceuEsQ}  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), h0 Xc=nj  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ? q_%  
nStartPos,nEndPos,i); A%cJ5dF8~  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); j 8)*'T  
fileSplitterFetch.start(); ,e^~(ITaq  
} Zu*7t<W  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), G{!(2D4!  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); x];i? 4  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", "rrw~  
nEndPos = " + nFileLength); {PkR6.XhR  
// fileSplitterFetch[nPos.length-1].start(); q|}O-A*wa  
<TTBIXV  
/:v}Ni"6nF  
//等待子线程结束 !sp`oM  
//int count = 0; D_?dy4\  
//是否结束while循环 82 dmlPwJC  
boolean breakWhile = false; :NL[NbQYt  
J|F!$m{  
?[|A sw1t  
while(!bStop) ^u2x26].  
{ / */"gz%  
write_nPos(); }qJ`nN8  
Utility.sleep(500); /BN=Kl]  
breakWhile = true; }G "EdhSl  
icQQLSU5  
($Op*bR  
for(int i=0;i<nStartPos.length;i++) $DaQM'-  
{ :r2d%:h%2  
if(!fileSplitterFetch.bDownOver) }KYOde@  
{ voFg6zoV_  
breakWhile = false; kxR!hA8wv4  
break; v cUGBGX_&  
} dOK]Su  
} )5`~WzA  
if(breakWhile) } lXor~_i  
break; DS9-i2  
2r!- zEV  
qnb/zr)p  
//count++; hE E1i  
//if(count>4) Z^BZH/I?  
// siteStop(); PC\p>6xT  
} J7sH]  
e _(';Lk  
-Mf-8zw8G  
System.err.println("文件下载结束!"); ^oYRB EIJH  
} 0|]d^bo  
catch(Exception e){e.printStackTrace ();} LqXVi80  
} 3ZN\F  
]9~Il#  
}ik N  
//获得文件长度 g{ ;OgS3>  
public long getFileSize() )H`V\ H[0P  
{ %Eugy  
int nFileLength = -1; ;n.h!wmJ}  
try{ G^cMY$?99  
URL url = new URL(siteInfoBean.getSSiteURL()); /;T tMQt  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); m?gGFxo  
httpConnection.setRequestProperty("User-Agent","NetFox"); YS@T Q?  
*Z\AO'h=Z  
$ce*W 9`  
int responseCode=httpConnection.getResponseCode(); Ly/  
if(responseCode>=400) {>PEl; ,-  
{ B873UN  
processErrorCode(responseCode); PJ=|g7I  
return -2; //-2 represent access is error r,3\32[?  
} `Z#':0Z  
/MMnW$)  
YNl".c  
String sHeader; Pe-rwM  
8_ascvs5  
j/q&qrlL  
for(int i=1;;i++) ~W={"n?=  
{ `DE_<l  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); +]( #!}oH  
//Utility.log(in.readLine()); `mI5Z*]-  
sHeader=httpConnection.getHeaderFieldKey(i); h6IO;:P)  
if(sHeader!=null) ji\&?%(B  
{ Jamt@=  
if(sHeader.equals("Content-Length")) ho)JY $#6  
{ WJ)4rQ$o  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); .LDp.#d9r1  
break; LitdO>%#2  
} k ]T  
} .XkD2~;  
else +sTPTCLE  
break; = y(*?TZH  
} H+5+;`;  
} Q1{9>NI  
catch(IOException e){e.printStackTrace ();} FA\U4l-  
catch(Exception e){e.printStackTrace ();} _>aP5g?Ep  
4;>HBCM4-  
oX*;iS X  
Utility.log(nFileLength); lWd@  
,jtaTG.>  
+Wgfxk'{  
return nFileLength; >)u{%@Rcy{  
} 8^D1u`  
]5K(}95&'  
<`G-_VI  
//保存下载信息(文件指针位置) +S+=lu _  
private void write_nPos() FC~%G&K/q^  
{ FV3[7w=D\  
try{ fYzP4  
output = new DataOutputStream(new FileOutputStream(tmpFile)); X$@qs9?)^  
output.writeInt(nStartPos.length); Ryygq,>VD.  
for(int i=0;i<nStartPos.length;i++) )FmIL(vu  
{ @H3x51PT(m  
// output.writeLong(nPos); kwqY~@W  
output.writeLong(fileSplitterFetch.nStartPos); ADVS}d!;]  
output.writeLong(fileSplitterFetch.nEndPos); k4!_(X%8  
} V1GkX =H},  
output.close(); VXlAK(   
} lzz;L z  
catch(IOException e){e.printStackTrace ();} )v11j.D  
catch(Exception e){e.printStackTrace ();} ms!|a_H7 r  
} ywkRH  
m2YsE  j7  
U* c'xoP  
//读取保存的下载信息(文件指针位置) -'L~Y~'.  
private void read_nPos() ,Vo[mB  
{ H3`.Y$z  
try{ ~'0ZW<X.  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); )n 1[#x^I  
int nCount = input.readInt(); F|R7hqf  
nStartPos = new long[nCount]; <2]D3,.g.  
nEndPos = new long[nCount]; _ WPt zL  
for(int i=0;i<nStartPos.length;i++) \x\N?$`ANc  
{ >T\@j\X4  
nStartPos = input.readLong(); IbJl/N%o  
nEndPos = input.readLong(); s$(%?,yf2  
} >dJ~  
input.close(); $+ N~Fa  
} `W" ;4A  
catch(IOException e){e.printStackTrace ();} O9o]4;  
catch(Exception e){e.printStackTrace ();}  UBj&T^j  
} #d*gWwnx"  
F u^j- Io  
b62B|0i  
private void processErrorCode(int nErrorCode) Ctn?O~u  
{ NI.ROk1{+4  
System.err.println("Error Code : " + nErrorCode); ;UUgqX#  
} #$W0%7  
4zt:3bW U  
Iz'Et'w8!  
//停止文件下载 q8-hbWNm4  
public void siteStop() CY{!BV'  
{ ^OX}y~'  
bStop = true; 3 =c#LUA`  
for(int i=0;i<nStartPos.length;i++) ;hV|W{=w  
fileSplitterFetch.splitterStop(); :g' 'GqGZ  
@Tq-3Um  
W[qy4\.B  
} ,EVPnH[F~  
} ]W4{|%@H"  
//负责部分文件的抓取 ;H`@x Lv*  
**FileSplitterFetch.java XEagN:  
*/ n-],!pL^  
package NetFox; zS|4@t\__  
JC-> eY"O2  
C& XPn;f  
import java.io.*; &Xh>w(u  
import java.net.*; ^Go,HiB  
Fw{#4  
ov H'_'  
public class FileSplitterFetch extends Thread { DO~[VK%|  
|e+3d3T35  
2#3`[+g<n  
String sURL; //File URL 1cMLl6Bp>  
long nStartPos; //File Snippet Start Position $d])>4eQ  
long nEndPos; //File Snippet End Position F E{c{G<  
int nThreadID; //Thread's ID |2n*Ds'  
boolean bDownOver = false; //Downing is over TOKt{`2}  
boolean bStop = false; //Stop identical +r//8&  
FileAccessI fileAccessI = null; //File Access interface UBM#~~sM  
$ BgaLJs/O  
+HRtuRv0T  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException &a e!lB  
{ rP2h9Cb  
this.sURL = sURL; D|m0Vj b  
this.nStartPos = nStart; #>\SK  
this.nEndPos = nEnd; );i J9+ V}  
nThreadID = id; fp\mBei  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 LVm']_K(f  
} @lWNSf  
QRKP;aYt  
2)\MxvfOh  
public void run() 4g2`[<S  
{ !jU{ }RCR  
while(nStartPos < nEndPos && !bStop) xoj,>[7 D  
{ Xf#;`*5  
`MCtm(<  
0F![<5X  
try{ SSla^,MHef  
URL url = new URL(sURL); k:j_:C&.  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &Z!y>k%6  
httpConnection.setRequestProperty("User-Agent","NetFox"); cC/32SmY4  
String sProperty = "bytes="+nStartPos+"-"; <oT1&C{  
httpConnection.setRequestProperty("RANGE",sProperty); L>E;cDB  
Utility.log(sProperty); Fq <JxamR  
v?6*n >R  
}1[s,  
InputStream input = httpConnection.getInputStream(); cpw=2vnD  
//logResponseHead(httpConnection); 7BwR ].  
: OjmaP  
WjR2:kT  
byte[] b = new byte[1024]; Wf5;~RJC?  
int nRead; oH v.EO  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) NT5##XOB  
{ na9YlJ\  
nStartPos += fileAccessI.write(b,0,nRead); \<xo`2b  
//if(nThreadID == 1) )16+Pm8  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 5Uy *^C7M^  
} UY({[?Se  
LY)Wwl*wc  
S *J{  
Utility.log("Thread " + nThreadID + " is over!"); Wtk|}>Pf  
bDownOver = true; 5%QYe]D  
//nPos = fileAccessI.write (b,0,nRead); W)]&G}U<  
} aZ{l6  
catch(Exception e){e.printStackTrace ();} [PiMu,O[v  
} SEg{Gso9b  
} we!w5./Xm  
T]1.":   
TNN@G~@cm  
//打印回应的头信息 AX6:*aZB  
public void logResponseHead(HttpURLConnection con) ecH7")  
{ Kf(Px%G6K  
for(int i=1;;i++) E>*Wu<<  
{ G,P k3>I'  
String header=con.getHeaderFieldKey(i); *\}$,/m['  
if(header!=null) 6|n3Q$p  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); sGNHA( ;  
Utility.log(header+" : "+con.getHeaderField(header)); vRW;{,d  
else QQ{*j7i)  
break; {g1R?W\LZ  
} h:C:opa-=  
} |x&4vHXR0  
MNTVG&h  
33eOM(`D[  
public void splitterStop() *sB'D+-/  
{ +lFBH(o]X  
bStop = true; cp~6\F;c  
} HA}q.L]#  
?z-nY,'^uq  
W=+AU!%  
} XUR#|  
&YD+ s%OL  
;O~FiA~`c  
/* >0 o[@gJl  
**FileAccess.java 5%V(eR  
*//文件访问(定位,写) qM 1ZCt  
package NetFox; aL;zN%Tw  
import java.io.*; 2sG1Hox  
CK4#ZOiaa  
>QN-K]YLL  
public class FileAccessI implements Serializable{ };"_Ku4#-  
=^*EM<WG)  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ']c;$wP  
RandomAccessFile oSavedFile; -AVT+RE9z  
long nPos; &,Loqr  
~p{YuW[e  
ouoIbA9X  
public FileAccessI() throws IOException /4+zT?f  
{ [5-Ik T0  
this("",0); g26_#4 P  
} H|j]uLZ  
;Z"Iv  
iGj,B =35  
public FileAccessI(String sName,long nPos) throws IOException rAW7Zp~KK  
{ ;H71A[M T  
oSavedFile = new RandomAccessFile(sName,"rw"); |FlB#  
this.nPos = nPos; L.K|]]u  
oSavedFile.seek(nPos); a5pM~.]  
} Pjvb}q=  
eL)m(  
iny/K/5bf  
public synchronized int write(byte[] b,int nStart,int nLen) %zEy.7Ux  
{ Sa.nUj{M=  
int n = -1; J?Q@f  
try{ ^:f)XZ  
oSavedFile.write(b,nStart,nLen); t)k;5B`> &  
n = nLen; tId,Q>zH  
} Ly v"2P  
catch(IOException e) Jzy:^PObT  
{ -\ew,y  
e.printStackTrace (); z [u!C/  
} l#+@!2z  
6*>vie  
hA&m G33  
return n; YxU->Wi]G  
} PIQd=%?'  
`r\/5|M  
d=\\ik8  
} f!GFRMM1  
P$clSJW  
76c:* bZ  
/* z!k  
**SiteInfoBean.java }ri7@HCY4  
*/  @_WZZ  
package NetFox; $\20Vgu<  
0PUSCka'6  
C'sA0O@O  
public class SiteInfoBean { $Nj'_G\}  
/>PH{ l  
8N#.@\'kz.  
private String sSiteURL; //Site's URL =fhRyU:C[z  
private String sFilePath; //Saved File's Path D42!#  
private String sFileName; //Saved File's Name |*]<*qnZt  
private int nSplitter; //Count of Splited Downloading File p8&rl|z|  
1x+w|h  
O#vIn}  
public SiteInfoBean() y,<\d/YY@  
{//nSplitter的缺省值为5 "*d%el\63  
//default value of nSplitter is 5 %]F{aR  
this("","","",5); /KO2y0`  
} ?i~mt'O  
7~D5Gy  
x:]_z.5  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) H3ob 8+J  
{ j(_6.zf  
sSiteURL= sURL;  /zir$  
sFilePath = sPath; ( M3-S5   
sFileName = sName; 5* ~E dT  
this.nSplitter = nSpiltter; 0{Zwg0&  
= o1&.v2j  
nC9x N  
} D r6u0rx8  
lOIf4  
-li;w tCS  
public String getSSiteURL() >+ Im:fD  
{ bGp3 V. H  
return sSiteURL; 7zXX& S  
} h~&5;  
DwXSlsN3v  
(xBWxeL~  
public void setSSiteURL(String value) k]A$?C0Q<%  
{ {r?Ly15  
sSiteURL = value; M_;hfpJZ  
} N#X(gEV  
>>h0(G|  
XO/JnJ^B  
public String getSFilePath() gvxOo#8]  
{ l;;"v) C8  
return sFilePath; ;J?zD9  
} {F*81q\  
>xm:?WR  
9,A HC2kn%  
public void setSFilePath(String value) /2]=.bLwz  
{ 53?B.\  
sFilePath = value; $4rMYEn08  
} Ap%tm)@1  
inv 5>OeG  
Cn8w}) B  
public String getSFileName() rp,PhS  
{ .h>tef  
return sFileName; 7?~*F7F  
} c_.4~>qw  
w 8oIq*  
L t.Vo  
public void setSFileName(String value) /AUXO]  
{ `F' >NNY  
sFileName = value; !>QD42  
} X!/  
aQ.mvuMa7'  
Qj/.x#T  
public int getNSplitter() Bis'59?U_  
{ Ni) /L( &  
return nSplitter; g{$F;qbkO  
} #~@Cl9[)D  
<+${gu?^  
@m(ja@YC  
public void setNSplitter(int nCount) jM|-(Es. )  
{ d"hW45L  
nSplitter = nCount; jMB&(r  
} !&8HA   
} xO` O$ie  
Oxhc!9F  
~OQ/ |ws  
/* T@,tlIM  
**Utility.java k_%"#  
*/ p:8&&v~I  
package NetFox; x5)YZ~5  
h`%}5})=  
h oL"K  
public class Utility { CYWL@<p,  
Z4'8x h)-  
P% ZCACzV  
public Utility() | ?])]F  
{ ZpTT9{PT=:  
F8%.-.l)  
2W 9N-t2 1  
} fu6Ir,  
57eA (uI  
//线程睡眠 5 U{}A\q  
public static void sleep(int nSecond) WTP~MJ#C  
{ 2wki21oY  
try{ )kiC/Y}k  
Thread.sleep(nSecond); [#Y7iN&  
} &>&UqWL  
catch(Exception e) D 4fHNk)kZ  
{ 8KrqJN0\  
e.printStackTrace (); ekx~svcC&A  
} Ps!~miN|>  
} U4hFPK<  
%Vp'^,&S  
//日志 2PrUI;J$  
public static void log(String sMsg) .W)%*~ O!;  
{ |X$O'Gf#n  
System.err.println(sMsg); Nn%[J+F  
} [b<AQFh<c  
`96PY !$u  
K_X10/#b&  
public static void log(int sMsg) Pa-p9]gq  
{ Lupug"p0   
System.err.println(sMsg); hLf<-NM  
} 7 P$>T  
} xJ18M@" j  
i{ " g 7  
:n} NQzs  
/* 2!+saf^-,  
**TestMethod.java ev_4!+ko  
*/ /T_@rm  
package NetFox; ?onTW2cG;  
vdLBf+Zi  
' *6S0zt  
public class TestMethod { <$]=Vaq  
#M5R>&?Jqz  
^t{2k[@  
public TestMethod() .0b$mSV[  
{ ///xx/weblogic60b2_win.exe  KDODUohC  
try{ d?uN6JH9  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); :t36]NM  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5);  *Fe  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ~ojH$=K>d  
fileFetch.start(); 8I X,q  
} 7;T6hKWV[  
catch(Exception e){e.printStackTrace ();} J XKqQxZ[X  
 ta\CZp  
~T_4M  
} /d\#|[S  
Jbrjt/OG#I  
\<bar ~  
public static void main(String[] args) cn~M: LW23  
{ )_\ZUem  
new TestMethod(); 6ofi8( n[  
} tXgsWG?v[H  
} *)6:yn  
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