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http断点续传简单实现(java)

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/* {d\erG(  
**SiteFileFetch.java g1Q^x/  
*/ 2&E1)^  
package NetFox; [?<"SJ,`  
import java.io.*; P!C!E/Jf5  
import java.net.*; ny5 = =C{9  
G 1{F_  
8k$iz@e  
public class SiteFileFetch extends Thread { rO% |PRP  
?Uzs^rsb  
D<[4}og&]  
SiteInfoBean siteInfoBean = null; //文件信息Bean \ A\a=A[  
long[] nStartPos; //开始位置 xo0",i f8  
long[] nEndPos; //结束位置 ,.` ";='o  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 WV5gH*uUa  
long nFileLength; //文件长度 ex8mA6g  
boolean bFirst = true; //是否第一次取文件 =|n NC  
boolean bStop = false; //停止标志 DT #1*&-  
File tmpFile; //文件下载的临时信息 VT1W#@`e-  
DataOutputStream output; //输出到文件的输出流 Eb`U^*A  
+]Oq{v:e  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) $;%-<*Co  
public SiteFileFetch(SiteInfoBean bean) throws IOException  Xc2Oa  
{ :K&   
siteInfoBean = bean; E[J7FgU)<S  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); tr2@{xb  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); M:W9h+z  
if(tmpFile.exists ()) XF1x*zc  
{ 0X\,!FL  
bFirst = false; >2 gemTy  
read_nPos(); 8jxgSB",  
} dOq*W<%  
else w \pD'1e  
{ S @\Pki+n[  
nStartPos = new long[bean.getNSplitter()]; aWVJx@f  
nEndPos = new long[bean.getNSplitter()]; JBdZ]  
} y&\ J  
raGov`  
GEq?^z~i  
^;B vd!  
} 9)sGnD;  
%@L(A1"#D  
7ZHM;_ -  
public void run() *k'oP~:fT  
{ 4YkH;!M>ji  
//获得文件长度 {4&G\2<^^  
//分割文件 @B$ Y`eK\  
//实例FileSplitterFetch "])X0z yM  
//启动FileSplitterFetch线程  *5 FSq  
//等待子线程返回 pB{QO4q n  
try{ j_SRCm~:  
if(bFirst) h2+vl@X  
{ q>w@W:tZ  
nFileLength = getFileSize(); 3|%Q{U  
if(nFileLength == -1) tv)x(MX  
{ s4lkhoN\t  
System.err.println("File Length is not known!"); \$s<G|<P  
} Py6c=&*  
else if(nFileLength == -2) Zi/l.=9n  
{ $O&P@8:Z  
System.err.println("File is not access!"); o[^%0uVF  
} 6}2vn5 E//  
else ,U2 /J  
{ J0w[vrs&]  
for(int i=0;i<nStartPos.length;i++) 3A]Y=gfa  
{ \`r5tQr  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); GiB3.%R`  
} a3 wUB  
for(int i=0;i<nEndPos.length-1;i++) aT"q}UTK  
{ [i.2lt#]  
nEndPos = nStartPos[i+1];  N\DEY]  
} GAbX.9[V  
nEndPos[nEndPos.length-1] = nFileLength; v')Fq[H  
} t#oY|G3O}  
} $k*E^~qT  
!l@IG C  
YY]JjMkU  
//启动子线程 {) 4D1  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; :{%6< j  
for(int i=0;i<nStartPos.length;i++) O'U0Y8HN  
{ 2t\a/QE)E  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 3> -/sii  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), |)i- c`x  
nStartPos,nEndPos,i); Y1txI  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); gm9e-QIHK  
fileSplitterFetch.start(); \?h +  
} /<s'@!W  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ROr$ Sz  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ;JA2n\iP,  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", w``t"v4  
nEndPos = " + nFileLength); yInW?3  
// fileSplitterFetch[nPos.length-1].start(); BqK|4-Pf  
k}l5v)m  
e{.2*>pH  
//等待子线程结束 "m):"  
//int count = 0; c[?S}u|['  
//是否结束while循环 nK1XJp  
boolean breakWhile = false; l%.3hId-  
=&xamA)  
d~uK/R-KD  
while(!bStop) Z T95g  
{ U/Z!c\r  
write_nPos(); jE2k\\<a  
Utility.sleep(500); |HI =ykfI  
breakWhile = true; {w}PV5<  
q .nsGbl  
[3;J,P=&  
for(int i=0;i<nStartPos.length;i++) z m\=4^X  
{ w<&Nn`V  
if(!fileSplitterFetch.bDownOver) ]K?z|&N|HK  
{ 4vPQuk!  
breakWhile = false; a*6x^R;)  
break; beEdH>  
} bSU9sg\  
} 2X;,s`)  
if(breakWhile) /!oi`8D  
break; ${ad[hs  
J %jf uj  
AnG/A!G  
//count++; AF ZHS\  
//if(count>4) [Nr6 qxWg  
// siteStop(); V' "p a  
} o;M"C[  
8},!t\j#]  
8b !&TP~m1  
System.err.println("文件下载结束!"); !0 `44Gbq  
} 9s6, &'  
catch(Exception e){e.printStackTrace ();} jY$Bns&.w  
} 2!cP[ Ck  
i;y<gm"  
[zn`vT  
//获得文件长度 Vd4x!Vk  
public long getFileSize() ;" '` P[  
{ k4'rDJfB  
int nFileLength = -1; ZGSb&!Ke  
try{ R0_%M  
URL url = new URL(siteInfoBean.getSSiteURL()); f8L  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); [{ K$sd  
httpConnection.setRequestProperty("User-Agent","NetFox"); F=Z|Ji#  
s{x2RDAt  
qxG @Zd  
int responseCode=httpConnection.getResponseCode(); m[!t7e  
if(responseCode>=400) Ex^7`-2,B  
{ #JYv1F  
processErrorCode(responseCode); ^O6PZm5J}  
return -2; //-2 represent access is error $d{{><  
} ;VeC(^-eh6  
!h}x,=`z/  
]}i_NqW)  
String sHeader; V9I5/~0c  
@sav8 ]  
3%|LMX]M5_  
for(int i=1;;i++) jl{>>TW{x  
{ k+'Rh'>  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ~A}"s-Kq5  
//Utility.log(in.readLine()); .d^8w97  
sHeader=httpConnection.getHeaderFieldKey(i); &sh %]o8  
if(sHeader!=null) }ARWR.7Cc  
{ #n]js7  
if(sHeader.equals("Content-Length")) 'D-eFJ5  
{ xV}E3Yj2#  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); !3v!BJ#+,&  
break; }?$d~]t)  
} y+_G L=J  
} K;,n?Q w  
else +IK~a9t  
break; 7]@vPr;:  
} gnlGL[r|  
} A/lxXy}D  
catch(IOException e){e.printStackTrace ();}  [53rSr  
catch(Exception e){e.printStackTrace ();} F +D2 xN@  
1mwb&j24n3  
@E{c P%fv  
Utility.log(nFileLength); ea3AcT6  
H\W60|z9  
^j[>.D  
return nFileLength; *$Aneq0f  
} xv]P-q0  
':R)i.TS  
iSUn}%YFz!  
//保存下载信息(文件指针位置) #b4`Wcrj  
private void write_nPos() .wtb7U;7  
{ #yFDC@gH1  
try{ i d\0yRBt  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 8O qG{jmG  
output.writeInt(nStartPos.length); n AQB  
for(int i=0;i<nStartPos.length;i++) <@.f#  
{ U`ey7   
// output.writeLong(nPos); ,oT?-PC$z  
output.writeLong(fileSplitterFetch.nStartPos); t~)w921>  
output.writeLong(fileSplitterFetch.nEndPos); wr~# rfH  
} MIub^ $<C  
output.close(); .!\y<9  
} 1RY}mq  
catch(IOException e){e.printStackTrace ();} Os?G_ziIB  
catch(Exception e){e.printStackTrace ();} m4<8v  
} UtIwrR[  
QzT)PtX  
;-~ Wfh+  
//读取保存的下载信息(文件指针位置) ~QJD.'z  
private void read_nPos() ?y>xC|kt  
{ Se9I1~mX  
try{ :aV(i.LW  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); O _yJR  
int nCount = input.readInt(); 4Smno%jq  
nStartPos = new long[nCount]; y>'^<xk  
nEndPos = new long[nCount]; OthQ)&pq X  
for(int i=0;i<nStartPos.length;i++) cR[)[9}  
{ W#$ pt>h)  
nStartPos = input.readLong(); Sir7TQ4B  
nEndPos = input.readLong(); .M!6${N);  
}  gG1%.q  
input.close(); >M<rr!|  
} Q1mz~r  
catch(IOException e){e.printStackTrace ();} d!{,[8&  
catch(Exception e){e.printStackTrace ();} &[`p qX  
} Vl5}m  
B=%cXW,  
 :J`:Q3@  
private void processErrorCode(int nErrorCode) ^:5 ;H=.  
{ %a<N[H3NV@  
System.err.println("Error Code : " + nErrorCode); SouPk/-B80  
} @aN<nd`q)  
n7i;^=9 mM  
.e!dEF)D  
//停止文件下载 3+u11'0=t  
public void siteStop() x$QOOE]  
{ ,'v]U@WK  
bStop = true; (Gf1#,/3~  
for(int i=0;i<nStartPos.length;i++) :/c=."z.  
fileSplitterFetch.splitterStop(); PaP47>(  
\|BtgT*$b  
B_i@D?bTD  
} '*MNRduE6  
}  ]hpocr  
//负责部分文件的抓取 3kx/Q#  
**FileSplitterFetch.java ),v[.9!}:  
*/ /Z';# G,z  
package NetFox; wQgW9546  
j#$ R.  
vQ2kL`@  
import java.io.*; q+.DZ @  
import java.net.*; rY4{,4V  
&s->,-,  
Pni  
public class FileSplitterFetch extends Thread { t%Vc1H2}  
$`(}ygmP  
;Xk-hhR  
String sURL; //File URL b? jRA^  
long nStartPos; //File Snippet Start Position %Ui&SZ\  
long nEndPos; //File Snippet End Position 'e_^s+l)a  
int nThreadID; //Thread's ID L,*2t JcC<  
boolean bDownOver = false; //Downing is over tPIT+1.]z  
boolean bStop = false; //Stop identical xgn@1.}G  
FileAccessI fileAccessI = null; //File Access interface ~ J^Gzl  
NVU@m+m~  
7pH(_-TF  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException |&`NB|  
{ }]$%aMxy T  
this.sURL = sURL; fNPHc_?Ybj  
this.nStartPos = nStart; kngkG|du  
this.nEndPos = nEnd; }26?bd@e`  
nThreadID = id; lCLz!k2di  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 v!27q*;8H  
} 7tP?([o%F  
9G_bM(q'^2  
i 2hP4<;h  
public void run() J3KY?,g3O_  
{ mRZC98$ @r  
while(nStartPos < nEndPos && !bStop) Y*/:IYr`  
{ 3?iRf6;n  
.0kltnB  
? acm5dN  
try{ .Qm"iOyM  
URL url = new URL(sURL); U+>!DtOYK  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();  }&BE*U8_  
httpConnection.setRequestProperty("User-Agent","NetFox"); ^\Tde*48  
String sProperty = "bytes="+nStartPos+"-"; _eb:"(m  
httpConnection.setRequestProperty("RANGE",sProperty); q4'szDYO2  
Utility.log(sProperty); CE]0OY  
S 1sNVW  
p \A^kX^5  
InputStream input = httpConnection.getInputStream(); o%XAw   
//logResponseHead(httpConnection); B{$4s8XU  
,*$L_itL  
A;7p  
byte[] b = new byte[1024]; 7nM]E_  
int nRead; xpCzx=n3.m  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) +EjH9;gx  
{ =cI -<0QSn  
nStartPos += fileAccessI.write(b,0,nRead); <@6K(  
//if(nThreadID == 1) 3>Y G  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); SxMmy  
} *yKw@@d+p  
A:PQIcR;V  
Wd#r-&!6j  
Utility.log("Thread " + nThreadID + " is over!"); /tR@J8pV  
bDownOver = true; G8dC5+h  
//nPos = fileAccessI.write (b,0,nRead); ,e$]jC<sv2  
} FDBj<uXfM|  
catch(Exception e){e.printStackTrace ();} ts%XjCN[  
} 7s@%LS  
} WP[h@#7<  
4>eY/~odq]  
1Z%^U ?  
//打印回应的头信息 B64L>7\>`  
public void logResponseHead(HttpURLConnection con) ,<R/jHZP9  
{ 0NrUB  
for(int i=1;;i++) @yiAi:v@  
{ H~IR:WOw  
String header=con.getHeaderFieldKey(i); `>KB8SY:qK  
if(header!=null) JAJo^}}{b  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); "#1KO1@G  
Utility.log(header+" : "+con.getHeaderField(header)); V'?bZcRr~  
else *`$Y!uzG:\  
break; q-gp;Fm  
} H8.Aq\2S  
} ,l/~epx4v)  
hG51jVYtw  
L c4\i  
public void splitterStop() ?# ~3%$>  
{ lZ]x #v  
bStop = true; tQ0iie1Ys  
} ?.Mw  
ERD( qL.J  
f$#--*  
} gS{hfDpk,h  
'-C%?*ku  
zURxXo/\V  
/* cV^r_E\m  
**FileAccess.java 6[ }~m\cY  
*//文件访问(定位,写) r9nH6 Md\  
package NetFox; ,dn6z#pb+  
import java.io.*; !qGER.  
4@ EY+p  
L3}n(K AJj  
public class FileAccessI implements Serializable{ 6r  
);EW(7KeL  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 XG_h\NIL  
RandomAccessFile oSavedFile; ^w]N#%k\H  
long nPos; yKupPp);  
pFE&`T@ <  
r\nKJdh;ka  
public FileAccessI() throws IOException dJyf.VJ  
{ X*f#S:kiNU  
this("",0); C>l{_J)n  
} ' cM2]<  
Nl"Xl?y}  
;MRK*sfw{  
public FileAccessI(String sName,long nPos) throws IOException I ACpUB  
{ V9aGo#  
oSavedFile = new RandomAccessFile(sName,"rw"); iA*^`NMaT  
this.nPos = nPos; ^na8d's:  
oSavedFile.seek(nPos); ]?KTw8j}  
} lO^Ly27  
y[QQopy4:  
NQB a+N  
public synchronized int write(byte[] b,int nStart,int nLen) W)F<<B,  
{ f};lH[B3y  
int n = -1; > mI1wV[  
try{ Pn?Ujjv  
oSavedFile.write(b,nStart,nLen); "rxhS; R1>  
n = nLen; /mS|Byx  
} R`M>w MLH  
catch(IOException e) &n6'r^[D  
{ mEK0ID\  
e.printStackTrace (); ( X(61[Lu  
} \tv^],^`  
tc-pVw:TV  
t<8vgdD  
return n; Oz8"s4Y7  
} Z8vMVo  
Ug :3)q[O  
K|n%8hRy  
} jhRg47A  
R#"LP7\  
<4lR  
/* B=<>OYH  
**SiteInfoBean.java 9, A(|g  
*/ =*paa  
package NetFox; WY>r9+A?W  
hM_0/o-  
qDSZ:36  
public class SiteInfoBean { hY*ylzr83  
.\Z/j  
kHWW\?O  
private String sSiteURL; //Site's URL 2EO WbN}M  
private String sFilePath; //Saved File's Path O_v8R7 {  
private String sFileName; //Saved File's Name +/"Ws '5E  
private int nSplitter; //Count of Splited Downloading File IBP3  
y4N8B:j%  
]|H`?L  
public SiteInfoBean() K)ZW1d;  
{//nSplitter的缺省值为5 h?Y->!'  
//default value of nSplitter is 5 11"- taWj  
this("","","",5); /#<R  
} V(gmC%6%l*  
qu8!fFQjYL  
R_DstpsT  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 1w` ]2  
{ /z=xEnU#  
sSiteURL= sURL; 2wCSjAWWh(  
sFilePath = sPath; 2OA0rH"v  
sFileName = sName; cWp5' e]A  
this.nSplitter = nSpiltter; W;Pdbf"  
3VI[*b  
S['rfD>9  
} B|\JGnNQ  
kjj4%0"  
d#tqa`@~  
public String getSSiteURL() i`nmA-Zj[  
{ YLX LaC[  
return sSiteURL; Gt4/ax:A@  
} |_6V+/?"?`  
kT-dQ32  
|2Krxi3*  
public void setSSiteURL(String value) %>];F~z  
{ 0 _n Pq  
sSiteURL = value; (7X|W<xT  
} RJpRsr  
zh.^> `   
y 4 wV]1  
public String getSFilePath() "V= IG{.  
{ I ~U1vtgp  
return sFilePath; )7aUDsu>4  
} *\-$.w)k  
&gxWdG}qx]  
B|f =hlY  
public void setSFilePath(String value) mBwM=LAZ  
{ _YK66cS3E/  
sFilePath = value; w$)NW57[|  
} C {*' p+f  
{+3 `{34e  
h]+UK14m  
public String getSFileName() u# TNW.  
{ '9ki~jtf=  
return sFileName; a<NZC  
} W>E/LBpE4  
\4`:~c  
5wE+p<-KX  
public void setSFileName(String value) JI3x^[(Z  
{ ron-v"!  
sFileName = value; %#jW  
} x]Pp|rHj  
,<CFjtelO  
6*aU^#Hz6  
public int getNSplitter() =,Zkg(M  
{ hl/) 1sOIR  
return nSplitter; FHK{cE  
} X7~^D[ X  
hEh` cBO  
%&5PZmnW  
public void setNSplitter(int nCount) /g]NC?  
{ K\trT!I  
nSplitter = nCount; 3 0.&Lzz  
} c:[8ng 2v  
} e0$.|+  
5r` x\  
6uTFgSqZ  
/* mB5Sm|{  
**Utility.java ufi:aE=}  
*/ L%`MoTpK q  
package NetFox; FKH_o  
<r1/& RW,  
KU=+ 1,Jf  
public class Utility { )z_5I (?&  
Be~ '@  
*'n L[]  
public Utility() 8yC/:_ML  
{ /8? u2 q  
*%ta5a  
LTTMxiq[*  
} iBt<EM]U/  
]~@uStHn  
//线程睡眠 7PW7&]-WQ  
public static void sleep(int nSecond) Pr_DMu  
{ .Cu0G1  
try{  u*m|o8  
Thread.sleep(nSecond); d6XdN  
} j0~ dJ#  
catch(Exception e) )tv~N7  
{ =.]{OT  
e.printStackTrace (); <dKHZ4  
} aT~=<rEDy  
} w+Y_TJ%  
dAr=X4LE  
//日志 { V$}qa{P  
public static void log(String sMsg) .Q!pQ"5  
{ s>I~%+V.?:  
System.err.println(sMsg); J(Fk@{!F.*  
} FvXpqlp  
n #S?fsQN  
:I2spBx  
public static void log(int sMsg) )E*-  
{ Kw =RqF  
System.err.println(sMsg); FM"[:&>  
} 1l s8h  
} ~hb;kc3  
8 +mW  
&e3pmHp'  
/* T`2a)  
**TestMethod.java v@,`(\Ca'  
*/ 7?ILmYBw  
package NetFox; 0C4Os p  
AbL(F#{  
}p>l,HD  
public class TestMethod { s[;1?+EI  
"9IR|  
X2mZ~RB(p  
public TestMethod() pD]2.O  
{ ///xx/weblogic60b2_win.exe )S9}uOG#  
try{ `4,]Mr1b  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); zgl$ n  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ge]Z5E(1  
SiteFileFetch fileFetch = new SiteFileFetch(bean); tP89gN^PA|  
fileFetch.start(); }\QXPU{UVd  
} zHD 8 \*  
catch(Exception e){e.printStackTrace ();} u`"Y!*[ -  
 N8)]d  
v)aV(Oa  
} r-_-/O"l  
eB9F35[  
v.53fx  
public static void main(String[] args) ? CU;  
{ R(s[JH(&  
new TestMethod(); W/.n R[!  
} I2gSgv%  
} J4Ca0Ag  
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