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http断点续传简单实现(java)

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/* X1Kze  
**SiteFileFetch.java yoTx3U@  
*/ )X6I #q8  
package NetFox; E< pO!P  
import java.io.*; *N](Xtbj  
import java.net.*; T+:GYab/  
Lp+?5DjLT  
/~g.j1g  
public class SiteFileFetch extends Thread { n]K{-C;  
Zj)A%WTD,  
Xx^v%[!`+  
SiteInfoBean siteInfoBean = null; //文件信息Bean Gd|jE  
long[] nStartPos; //开始位置 ZCDXy  
long[] nEndPos; //结束位置 ;v ~xL!uQ  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Fl\kt.G  
long nFileLength; //文件长度 Ujvk*~:  
boolean bFirst = true; //是否第一次取文件 !A+jX7Nb  
boolean bStop = false; //停止标志 uzT>|uu$  
File tmpFile; //文件下载的临时信息 j^Ln\N]^  
DataOutputStream output; //输出到文件的输出流 iUS?xKN$~-  
\~T&C5  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) G%%5lw!y'  
public SiteFileFetch(SiteInfoBean bean) throws IOException c}2"X,  
{ u TmT'u:}  
siteInfoBean = bean; `t7GYmw^#  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); |W SvAM3  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); FCChB7c`  
if(tmpFile.exists ()) P_E xh]P  
{ Emv9l~mIu  
bFirst = false; ]/Cu,mX  
read_nPos(); 2'?C  
} }5u;'>$  
else ?cD_\~  
{ "@itn  
nStartPos = new long[bean.getNSplitter()]; K3`48,`?wA  
nEndPos = new long[bean.getNSplitter()]; %:Zp7O2UB'  
} bhCAx W  
|3gWH4M4**  
|(5|6r3  
ro^T L  
} a*o k*r  
l R^W*w4y  
zzX9Q:  
public void run() Rm@F9D[,  
{ nyPW6VQ0n  
//获得文件长度 W\z<p P  
//分割文件 uJJP<mDgA  
//实例FileSplitterFetch DjiWg(X  
//启动FileSplitterFetch线程 `^DP<&{  
//等待子线程返回 bE"J&;|  
try{ 5pq9x4&  
if(bFirst) '>% c@C[  
{ l i2/"~l  
nFileLength = getFileSize(); "IoY$!Hk  
if(nFileLength == -1) t=dZM}wj_\  
{ :LD+B1$y  
System.err.println("File Length is not known!"); ^bXCYkx  
} R-\"^BV#Z  
else if(nFileLength == -2) H&0S  
{ 4$4n9`odE  
System.err.println("File is not access!"); .u;'eVH)a}  
} ^I!gteU;  
else iBqIV  
{ / gE9 W  
for(int i=0;i<nStartPos.length;i++) `e+eL*rZ~  
{ 9`DY6qfly  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); jq+:&8!8(e  
} Z DnAzAR  
for(int i=0;i<nEndPos.length-1;i++) -V}ZbXJD  
{ &fifOF#[ e  
nEndPos = nStartPos[i+1]; \LDcIK=  
} Wu693<  
nEndPos[nEndPos.length-1] = nFileLength; (9!kKMQW'  
} :$oiP  
} 15!b]':  
`wNJ*`  
l78 :.  
//启动子线程 A Zv| |8p  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ~;nW+S$o  
for(int i=0;i<nStartPos.length;i++) [,mcvO;  
{ 9S)A6]  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), :']O4v#^  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), S3YAc4  
nStartPos,nEndPos,i); "QV1G'  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); SrXuiiK  
fileSplitterFetch.start(); r A9Rz^;xa  
} 9!Vp-bo  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), `O}bPwa{>  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); '8fh(`  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 'a enh j  
nEndPos = " + nFileLength); hFt~7R  
// fileSplitterFetch[nPos.length-1].start(); 2pAshw1G  
x`p3I*_HT5  
.y~~[QF}8  
//等待子线程结束 X]t *  
//int count = 0; )jN fQ!?/  
//是否结束while循环 SP5t=#M6  
boolean breakWhile = false; u5dyhx7  
o`[X _  
?a-}1A{  
while(!bStop) XBHv V05mv  
{ }i2dXC/  
write_nPos(); WFpR@53Db  
Utility.sleep(500); s&qr2'F+z  
breakWhile = true; &bS!>_9  
n0ls a@l  
IN94[yW{1  
for(int i=0;i<nStartPos.length;i++) r#K"d  
{ 58_aI?~>>  
if(!fileSplitterFetch.bDownOver) {,i='!WIm  
{ 2v\-xg%1  
breakWhile = false; .@]M'S^1  
break; ^b(> Bg )T  
} =DXvt5G  
} IctLhYZ  
if(breakWhile) dLTA21b#  
break; \)9R1zp/x  
>.#tNFAs  
E{6X-C[)v  
//count++; =u]FKY  
//if(count>4) Nh\y@\F>  
// siteStop(); t8FgQ)tk  
} =;A~$[g  
U HUO9h  
rzgzX  
System.err.println("文件下载结束!"); wenJ(0L|  
} %uhhQ<zs%  
catch(Exception e){e.printStackTrace ();} RlTVx :  
} We*c_;@<  
Q Ph6 p3bg  
zs@[!?A,  
//获得文件长度 d@t3C8  
public long getFileSize() yj{:%Km:`  
{ j\8'P9~%  
int nFileLength = -1; -2Azpeh  
try{ uDi#a~m@  
URL url = new URL(siteInfoBean.getSSiteURL()); %uLyL4*L(p  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9CTvG zkw  
httpConnection.setRequestProperty("User-Agent","NetFox"); A)q,VSR8  
4lfJc9J  
"t" &6\  
int responseCode=httpConnection.getResponseCode(); >zAI#N4  
if(responseCode>=400) H@WQO]P A  
{ QabYkL5@  
processErrorCode(responseCode); [M6/?4\  
return -2; //-2 represent access is error r#[YBaCZJ  
} OHha5n  
0,`$KbV\  
E={W^k!Vz:  
String sHeader; :WBl0`kW]4  
f*SAbDE  
>K;'dB/m;1  
for(int i=1;;i++) MhpR^VM'.  
{ .U !;fJ9  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 3 e9fziQ~  
//Utility.log(in.readLine()); SbW6O_   
sHeader=httpConnection.getHeaderFieldKey(i); ba   
if(sHeader!=null) O(E-ox~q  
{ &Wup 7  
if(sHeader.equals("Content-Length")) ZVek`Cc2  
{ (_lc< Bj  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 'u2Qq"d+  
break; AFSFXPl "  
} ?k:i3$  
} S[ ,r .+  
else h&6x.ps@  
break; lEC58`Ws  
} ai ,Mez  
} ]jzINaMav  
catch(IOException e){e.printStackTrace ();} =JnUTc _u  
catch(Exception e){e.printStackTrace ();} ico(4KSk  
c!%:f^7g  
'HV}Tr  
Utility.log(nFileLength); o*u A+7n  
,uP1U@Cas  
uv[e0,@  
return nFileLength; G#4cWn'  
} %j=,c{`Q  
7>m#Y'ppl@  
+6{KrREX)  
//保存下载信息(文件指针位置) ngJES` 0d  
private void write_nPos() VRoeq {  
{ G#! j`  
try{ (Rk g  
output = new DataOutputStream(new FileOutputStream(tmpFile)); w`Dzk. 2  
output.writeInt(nStartPos.length); EF{_-FXY  
for(int i=0;i<nStartPos.length;i++) &~Q ?k  
{ JPk3T.qp  
// output.writeLong(nPos); Q=9S?p M  
output.writeLong(fileSplitterFetch.nStartPos); .0q %A1H  
output.writeLong(fileSplitterFetch.nEndPos); y*6r&989  
} :LFw J  
output.close(); yXw xq(32  
} BI=Ie?  
catch(IOException e){e.printStackTrace ();} g5to0  
catch(Exception e){e.printStackTrace ();} \?fl%r2  
} EQ>bwEG  
.-N9\GlJ,d  
* #;rp~  
//读取保存的下载信息(文件指针位置) um&e.V)N  
private void read_nPos() +-#| M|a  
{ E4[\lX$J  
try{ 9=I(AYG{m  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 6#5@d^a  
int nCount = input.readInt(); !{SU G+.2  
nStartPos = new long[nCount]; @11voD  
nEndPos = new long[nCount]; ?kb\%pcK  
for(int i=0;i<nStartPos.length;i++) r/L3j0  
{ DRV vW6s  
nStartPos = input.readLong(); (.!q~G  
nEndPos = input.readLong(); N1(}3O  
} SJ7>*Sa(u$  
input.close(); Z-H Kdv!d  
} u6jJf@!ws  
catch(IOException e){e.printStackTrace ();} (s{%XB:K  
catch(Exception e){e.printStackTrace ();} s:cS 9A8  
} 0tB9X9:,  
sa+:c{  
rsP-?oD8)  
private void processErrorCode(int nErrorCode) $b$r,mc  
{ yZFv pw|g  
System.err.println("Error Code : " + nErrorCode); 6M$.gX G.  
} Qq]UEI `Go  
bTHa;* `  
^ I,1kl~i  
//停止文件下载 xyz-T1ib  
public void siteStop() EGGy0ly  
{ XW]|Mv[M  
bStop = true; 1xq1te)  
for(int i=0;i<nStartPos.length;i++) Yjk A^e  
fileSplitterFetch.splitterStop(); }.zgVL L  
~rY<y%K  
wQnr*kyza  
} 7qXgHrr0|U  
} &"C1XM  
//负责部分文件的抓取 W.:k E|a.g  
**FileSplitterFetch.java %v~j10e  
*/ ZVIBmx  
package NetFox; iJrscy-  
o ohf))  
+bf%]   
import java.io.*; 6x/ X8zu  
import java.net.*; 6nGDoW#  
E4y"$U%.  
! 2Y, a  
public class FileSplitterFetch extends Thread {  |Be.r{l  
-R7f/a8  
R?|_` @@A  
String sURL; //File URL [EGE|   
long nStartPos; //File Snippet Start Position $X*$,CCIB  
long nEndPos; //File Snippet End Position `O}. .N]g  
int nThreadID; //Thread's ID <6L$ :vT_  
boolean bDownOver = false; //Downing is over gi;V~>kh  
boolean bStop = false; //Stop identical 6u:5]e8  
FileAccessI fileAccessI = null; //File Access interface `&9#!T.  
<"[}8  
Dh +^;dQ6  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException nVyb B~.=  
{ 9'5,V{pj  
this.sURL = sURL; RXx +rdF0  
this.nStartPos = nStart; [>_( q|A6+  
this.nEndPos = nEnd; W+K=M*^D;c  
nThreadID = id; P<4jY?.  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 R?&S]?H  
} #{ Uk4  
Q}fAAZ&7h  
rX{|]M":T  
public void run() =h_4TpDQ  
{ ^*{ xTB57  
while(nStartPos < nEndPos && !bStop) @#Xzk?+  
{ 3UN Jj&-`  
!&'xkw`  
b$Uwj<v  
try{ %W&=]&L  
URL url = new URL(sURL); F~l3?3ZV  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ?ST}0F00}  
httpConnection.setRequestProperty("User-Agent","NetFox"); Yaa M-o  
String sProperty = "bytes="+nStartPos+"-"; q75F^AvH  
httpConnection.setRequestProperty("RANGE",sProperty); 1@nR.v"$  
Utility.log(sProperty); p6HZ2Q:a  
RXWjFv~/  
e&0B4wVAQ  
InputStream input = httpConnection.getInputStream(); ` chf8  
//logResponseHead(httpConnection); y6PAXvv'{  
3.dUMJ$_  
jZ{S{"j  
byte[] b = new byte[1024]; HK[sHB&  
int nRead; aF;&#TsB  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ,<vrDHR  
{ "]NQTUb;  
nStartPos += fileAccessI.write(b,0,nRead); $Jr`4s  
//if(nThreadID == 1) nO|S+S_9  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); zA"D0fr  
} Q^p@ 1I  
+tV(8h4  
*UyV@  
Utility.log("Thread " + nThreadID + " is over!"); TM^1 {0;r5  
bDownOver = true; /t9w%Y  
//nPos = fileAccessI.write (b,0,nRead); q/B+F%QiMQ  
} ASYUKh,h  
catch(Exception e){e.printStackTrace ();} vSnb>z1  
} %cm5Z^B1"  
} a<Ns C1  
FQ-(#[  
Maa.>2v<  
//打印回应的头信息 rL,)Tc|"  
public void logResponseHead(HttpURLConnection con) YwF6/JA0^  
{ =6W:O  
for(int i=1;;i++) Zgg7pL)#c  
{ @Op8^8$`  
String header=con.getHeaderFieldKey(i); l =_@<p  
if(header!=null) 0zTv'L  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); <7jb4n<  
Utility.log(header+" : "+con.getHeaderField(header)); yav)mO~QU6  
else tm|lqa  
break; T*{zL  
} R/Y/#X^b  
} tAC,'im:*  
 CMg83  
rvmI 8  
public void splitterStop() )-QNWN H  
{ 18n84RkI9  
bStop = true; `Eu(r]:W  
} R Nv<kw  
HJ'93,  
bNaUzM!,H  
}  R_N<j  
?}]kIK}MC  
hL3,/^;E,  
/* 5{u6qc4FW  
**FileAccess.java G4{qWa/  
*//文件访问(定位,写) ipzUF o<w  
package NetFox; u:S@'z>  
import java.io.*; &=?`;K  
m+m6"yE#_  
NSgHO`gU8  
public class FileAccessI implements Serializable{ ( Lu.^  
>C-_Zv<!T\  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 F889JSZ%  
RandomAccessFile oSavedFile; wU ; f   
long nPos; 1IlR  
&Bp\kv  
|be r:1  
public FileAccessI() throws IOException ZKR z=(  
{ (wlsn6h  
this("",0); wrO>#`Z  
} rqFs[1wr>R  
vl5n%m H>^  
mWusRgj+8  
public FileAccessI(String sName,long nPos) throws IOException Ad,r(0a LZ  
{ qbEj\ b[  
oSavedFile = new RandomAccessFile(sName,"rw"); 9V66~Bf5  
this.nPos = nPos; Ds G *  
oSavedFile.seek(nPos); `Of wl%G  
} eTF8B<?  
PD}R7[".>  
rq1kj 8%2  
public synchronized int write(byte[] b,int nStart,int nLen) %)/f; T6  
{ *3/7wSV:  
int n = -1; IP'igX  
try{ @gqw]_W  
oSavedFile.write(b,nStart,nLen); `es($7}P_W  
n = nLen; @*DIB+K  
} p-pw*wH0  
catch(IOException e)  (v`;ym  
{ FR}H$R7#  
e.printStackTrace (); . ?p}:  
} &1p8#i  
+r0eTP=zf  
4{DeF@@  
return n; bS<@Rd{g  
} Jrk^J6aa  
}R1`ThTM  
2Z O'X9  
} j>o +}p?3I  
B (1,Rq[  
_onp%*  
/* p0rwiBC=q  
**SiteInfoBean.java eCp|QSXE  
*/ >$mSF Jz5S  
package NetFox; hf<$vRti>  
UPKi/)C;  
7rSUSra  
public class SiteInfoBean { ^@Qi&g`lr?  
lk +K+Ra/  
DVhTb  
private String sSiteURL; //Site's URL ;1.>"zX(  
private String sFilePath; //Saved File's Path mbBRuPEa=u  
private String sFileName; //Saved File's Name R1.sq(z`  
private int nSplitter; //Count of Splited Downloading File &#@>(u: .  
i$ L]X[  
eU koVr   
public SiteInfoBean()  j/9QV  
{//nSplitter的缺省值为5 KupMndK  
//default value of nSplitter is 5 CjQ"oQw  
this("","","",5); 5FSv"=  
} , Ln   
u- [t~-(a  
T'M66kg  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Q==v!"Gi|  
{ jAK{<7v4U  
sSiteURL= sURL; #tZf>zrs  
sFilePath = sPath; AD@PNM  
sFileName = sName; u 7"VeTz  
this.nSplitter = nSpiltter; Tj=dL  
_GO+fB/Q1  
HqdJdWl#"  
} {(OIu]:  
e5ru:#P.p  
*>'2$me=  
public String getSSiteURL() h)_Gxe"x  
{ sJb)HQ,7x  
return sSiteURL; DAnb.0  
} [tqO}D  
jRG\C=&(x  
kz0=GKic  
public void setSSiteURL(String value) 2Nn1-wdhb  
{ n`)7Y`hBhP  
sSiteURL = value; .H^P2tp  
} 'yd@GQM&  
90T%T2K  
-2& i)S0R  
public String getSFilePath() mhk/>+hF  
{ 3fxNV<  
return sFilePath; _E6} XNS  
} o}=.  
ufCqvv>'  
u:k:C  
public void setSFilePath(String value) Mjj}E >&  
{ y-#  
sFilePath = value; "XNu-_$N<a  
} =#(0)p $EC  
i7nL_N  
h `ME(U~<<  
public String getSFileName() :,kU#eZ$-  
{ Vf 0fT?/K  
return sFileName; n}A?jOSAe  
} xHB/]Vd-  
o-~~,n\  
nMG rG  
public void setSFileName(String value) |rFR8srPG  
{ -2\ZzK0tM  
sFileName = value; /zG +]  
} gcg>Gjp  
i_u {5 U;  
2L2 VVO  
public int getNSplitter() 1n'$Ji7  
{ YOV :  
return nSplitter; 5g``30:o  
} WRD A `  
2@ 9pr  
W|dpFh`  
public void setNSplitter(int nCount) MBB5wj  
{ r219M)D?  
nSplitter = nCount; 9 g Bjxqm  
} 3;a R\:p@w  
} ,?g=U8y|  
sEce{"VC  
^/>Wr'w   
/* 4\N_ G @  
**Utility.java J/'M N  
*/ wE$s'e  
package NetFox; 5"JU?e59M  
F7{R~mS;  
c>ad0xce6  
public class Utility { 1")FWN_K/T  
p9-0?(]  
lC#RNjDp/~  
public Utility() G02ox5X  
{ !4R>O6k   
74K)aA  
TbLe6x  
} vv+D*e&<  
*hVb5CS  
//线程睡眠 BeK2;[5C  
public static void sleep(int nSecond) Ge~q3"  
{ <EMkD1e  
try{ =m}TU)4.  
Thread.sleep(nSecond); ^m*3&x8  
} E4+b-?PB~  
catch(Exception e) $$JIBf8  
{ ~TDzq -U)  
e.printStackTrace (); 4`nqAX~'f  
} ?6i;)eIOI  
} L=,OZ9aA  
}YQ:6I  
//日志 &=6%>  
public static void log(String sMsg) <cYp~e%xIw  
{ &hayR_F9  
System.err.println(sMsg); cd!|Ne>fe  
} W57&\PXYn  
kMy<G8 s  
2H[ ; v+  
public static void log(int sMsg) 0p-#f|ET  
{ FV A UR  
System.err.println(sMsg); _J,xT  
} flG=9~qcGQ  
} t5paY w-b  
R"*R99  
:BZMnCfA  
/* R2w`Y5#`  
**TestMethod.java &5u BNpH  
*/ Y0@yD#,0~  
package NetFox; *Bs^NU.  
ic-IN~J-  
ASW4,%cl  
public class TestMethod { ivfXat-  
#{x5L^v>]  
@l~7 x  
public TestMethod() H"+wsM^@  
{ ///xx/weblogic60b2_win.exe exQ#<x*  
try{ &]< 3 ~6n  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 66Gx.tE  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); (S F1y/g@=  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Z:@6Lv?CN  
fileFetch.start(); _gW{gLYyJ  
} )lh8 k {  
catch(Exception e){e.printStackTrace ();} &~#iIk~%  
DLi?'K3t  
XJSa]P^B1  
} R& #tSL  
7^MX l  
d+6]u_J  
public static void main(String[] args) ;i\C]*  
{ F$Q04Qw  
new TestMethod(); RN[]Jt#6  
} <Ct_d Cc  
}  (#o t^  
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