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http断点续传简单实现(java)

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/* 'L-DMNxBr  
**SiteFileFetch.java o|xZ?#^h  
*/ dFDf/tH  
package NetFox; i}P{{kMJ  
import java.io.*; ;RX u}pd  
import java.net.*; v=0G&x=/  
3Jlap=]68S  
4oueLT(zc  
public class SiteFileFetch extends Thread { O !{YwE8x9  
V+y"L>K  
h9CTcWGt  
SiteInfoBean siteInfoBean = null; //文件信息Bean ^V#,iO9.-  
long[] nStartPos; //开始位置 uC#@qpzy  
long[] nEndPos; //结束位置 /]5*;kO`  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 dt,Z^z+" E  
long nFileLength; //文件长度 d[J_iD{ &  
boolean bFirst = true; //是否第一次取文件 ^ r(My}  
boolean bStop = false; //停止标志 D9A%8o  
File tmpFile; //文件下载的临时信息 jVQ89vf ~  
DataOutputStream output; //输出到文件的输出流 RR ^7/-  
DyiJ4m}kh  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) X!^|Tass  
public SiteFileFetch(SiteInfoBean bean) throws IOException 9J?s:"j  
{ -~lq <M  
siteInfoBean = bean; xk% 62W  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 25-h5$s  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); megTp  
if(tmpFile.exists ()) AH5;6Q  
{ htR.p7&Tn  
bFirst = false; p/VVb%  
read_nPos(); t4G$#~  
} _ `&l46  
else ByJPSuc D  
{ vno/V#e$WX  
nStartPos = new long[bean.getNSplitter()];  e]1Zey  
nEndPos = new long[bean.getNSplitter()]; ^N|8 B?Vg  
} o!K DeY  
dCTyfXou[=  
OQB7C0+ &  
HNv~ZAzBG-  
} [K\b"^=<  
2wIJ;rh  
!e~[U-  
public void run() C` ky=  
{ >20dK  
//获得文件长度 `(0B09~7  
//分割文件 z<vh8dNl  
//实例FileSplitterFetch 4,c6VCw3+  
//启动FileSplitterFetch线程 SnQT1U%  
//等待子线程返回 ybE 2N  
try{ YnU)f@b#  
if(bFirst) T!KwRxJ23  
{ HdI)Z<Krp  
nFileLength = getFileSize(); 9%iQ~   
if(nFileLength == -1) BB(6[V"SV  
{ *Z_4bR4Q  
System.err.println("File Length is not known!"); D\-\U E/  
} {#k[-\|;  
else if(nFileLength == -2) CL4N/[UM  
{ 8Ejb/W_  
System.err.println("File is not access!"); *1<kYrB  
} iI";m0Ny  
else s) shq3O  
{ dM^Z,; u  
for(int i=0;i<nStartPos.length;i++) #Ir?v  
{ 0O>ClE~P  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); R8Vf6]s_  
} Q'jw=w!|g  
for(int i=0;i<nEndPos.length-1;i++) ikV;]ox  
{ mL48L57Z  
nEndPos = nStartPos[i+1]; 3EICdC  
} ^.!jD+=I  
nEndPos[nEndPos.length-1] = nFileLength; hyf ;f7`o  
} 71{jedT  
} A+0-pF2D  
}QE*-GVv]  
u/u(Z&  
//启动子线程 c Pf_B=  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; U*$xR<8v  
for(int i=0;i<nStartPos.length;i++) @i;)`k5b  
{ ?e<2'\5v  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }ARA K^%  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), K8_v5  
nStartPos,nEndPos,i); HT.*r6Y>g  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); yQ N{)rv  
fileSplitterFetch.start(); 7}UG&t{  
} 6_bL<:xtY  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), =zcvR {Dkp  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); CC`_e^~y=F  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", \toU zTT  
nEndPos = " + nFileLength); $3g{9)}  
// fileSplitterFetch[nPos.length-1].start(); lbBWOx/|  
i#`q<+/q  
\H@1VgmR;  
//等待子线程结束 c_D(%Vf5  
//int count = 0; _b~{/[s  
//是否结束while循环 aLGq<6Ja  
boolean breakWhile = false; hDW!pnj1  
|j`73@6   
c Rq2 re  
while(!bStop) VIP7j(#t_g  
{ =\WF +r]V  
write_nPos(); 1^}I?PbqV  
Utility.sleep(500); ^ U*y*l$  
breakWhile = true; *(?Wzanh  
Sz go@x$^  
wwB3m&  
for(int i=0;i<nStartPos.length;i++) Lz'VQO1U=  
{ *7jz(iX  
if(!fileSplitterFetch.bDownOver) Q S&B"7;g  
{ rTIu'  
breakWhile = false; 6(f 'P_*  
break; VWvSt C  
} LZRg%3.E  
} xf]K  
if(breakWhile) ]$@D=g,r  
break; ;mG*Rad  
`.W2t5 Y  
`x`[hJ?i  
//count++; + O.-o/  
//if(count>4) (?na|yd  
// siteStop(); 9qB0F_xl  
} S' j g#*$  
tNi>TkC}`  
\g39>;iR  
System.err.println("文件下载结束!"); FQDf?d5  
} ecghY=%  
catch(Exception e){e.printStackTrace ();} Hsf::K x  
} _5jT}I<k  
N>!:bF  
H4w\e#|  
//获得文件长度 k2U*dn"9U  
public long getFileSize() ?BnU0R_r]  
{ (j&:  
int nFileLength = -1; \!-BR0+y;  
try{ "+F'WCJ-(*  
URL url = new URL(siteInfoBean.getSSiteURL()); (jM0YtrD  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); $oK&k}Q  
httpConnection.setRequestProperty("User-Agent","NetFox"); CJ :V%|  
!qt2,V  
Pb#M7=J/  
int responseCode=httpConnection.getResponseCode(); g"!(@]L!@  
if(responseCode>=400) "?I#!t%'  
{ /o;M ?Nt6  
processErrorCode(responseCode); <-umeY"n>  
return -2; //-2 represent access is error Wh)D_  
} d#g))f;  
w7V\_^&Id  
7Q}pKq]P  
String sHeader; sS>b}u+v#!  
%c }V/v_h  
pjWRd_h.  
for(int i=1;;i++) Yq+ 1kA  
{ kJWg},-\  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 7>JTQ CJ  
//Utility.log(in.readLine()); d~LoHp  
sHeader=httpConnection.getHeaderFieldKey(i); ')y2W1  
if(sHeader!=null) ]:|B).  
{ .,bpFcQ  
if(sHeader.equals("Content-Length")) ;A*SuFbV  
{ &|/_"*uM  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); L8VOiK=,  
break; ;o_F<68QP  
} !(GyOAb  
} P!eo#b^S  
else Y}:~6`-jj  
break; k{}> *pCU  
} gxv^=;2C  
} m\L`$=eO8  
catch(IOException e){e.printStackTrace ();} JE?rp1.  
catch(Exception e){e.printStackTrace ();} 3e_tT8  
/Nf{;G!kg  
$TI^8 3  
Utility.log(nFileLength); i+Z)`  
O$,F ga  
)U@9dV7u  
return nFileLength; 95l)s],  
} u\]EG{w(  
! _S#8"  
~||0lj.D  
//保存下载信息(文件指针位置) ~KBa-i%o  
private void write_nPos() kA:mB;:  
{ v/+ <YU  
try{ Re$h6sh  
output = new DataOutputStream(new FileOutputStream(tmpFile)); G;Li!H  
output.writeInt(nStartPos.length); Nd~B$venh  
for(int i=0;i<nStartPos.length;i++) s2; ~FK#/  
{ uoS:-v}/Y~  
// output.writeLong(nPos); G{U#9   
output.writeLong(fileSplitterFetch.nStartPos); IiU> VLa  
output.writeLong(fileSplitterFetch.nEndPos); XB)D".\  
} U\KMeaF5e-  
output.close(); M.W X&;>  
} T ozx0??)  
catch(IOException e){e.printStackTrace ();} (bsx|8[  
catch(Exception e){e.printStackTrace ();} U"PcNQy  
} (2g a: }K  
;8sL  
f9.?+.^_  
//读取保存的下载信息(文件指针位置) BI1M(d#1L"  
private void read_nPos() ,>;21\D  
{ aZFpt/.d  
try{ I Dohv[#  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); *WwM"NFHDd  
int nCount = input.readInt(); W0qR? jc  
nStartPos = new long[nCount]; rq+_ [!  
nEndPos = new long[nCount]; _olQ;{ U:  
for(int i=0;i<nStartPos.length;i++) y>I2}P  
{ l5[5Y6c>  
nStartPos = input.readLong(); 2Ez<Iw  
nEndPos = input.readLong(); E9:@H;Gc  
} #[+# bw_6  
input.close(); LOh2eZ"n  
} M<vPE4TIr*  
catch(IOException e){e.printStackTrace ();} SyWZOE%p  
catch(Exception e){e.printStackTrace ();} :gVUk\)  
} V ao:9 ~  
n6/Ous  
WyN ;lId  
private void processErrorCode(int nErrorCode) 0dch OUj  
{ Z(mUU]  
System.err.println("Error Code : " + nErrorCode); \ TV  
} Rs%`6et}\  
1[FN: hm  
5^B79A"}  
//停止文件下载 nV' 1 $L#  
public void siteStop() V=O52?8  
{ zF1!a  
bStop = true; Abc{<4 z0?  
for(int i=0;i<nStartPos.length;i++) [9m3@Yd'  
fileSplitterFetch.splitterStop(); FK%b@/7s~  
%w;qu1j  
&V].,12x  
} Jj4 HJ9  
} I2Xd"RHN  
//负责部分文件的抓取 @\K[WqF$$q  
**FileSplitterFetch.java vsY?q8+P  
*/ WtT;y|W  
package NetFox; ~6G `k^!  
&7L7|{18  
@X==[gQ  
import java.io.*; q+ax]=w  
import java.net.*; MpV<E0CmE  
/bo}I-<2  
Z)?$ZI@  
public class FileSplitterFetch extends Thread { <kh.fu@.Q  
-F5B Jk  
honh 'j  
String sURL; //File URL X1j8tg  
long nStartPos; //File Snippet Start Position iT]t`7R  
long nEndPos; //File Snippet End Position Rh>B# \  
int nThreadID; //Thread's ID $7x2TiAL  
boolean bDownOver = false; //Downing is over s8h*nZ)v  
boolean bStop = false; //Stop identical +QChD*  
FileAccessI fileAccessI = null; //File Access interface #:K=zV\  
F/5&:e?( )  
 :eN&wQ5q  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException tsXKhS;/w  
{ + G@N  
this.sURL = sURL; zl0{lV  
this.nStartPos = nStart; Ak'=l;  
this.nEndPos = nEnd; _imuyt".+  
nThreadID = id; c%H' jB [  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 K~W(ZmB  
} EVmBLH-a  
6^`iuC5  
eqx }]#  
public void run() 1I Xtu   
{ )Z7Vm2a  
while(nStartPos < nEndPos && !bStop) X\^V{v^-  
{ 2]!@)fio`  
xS*UY.>  
u]p21)m$x  
try{ d:kB Zrq  
URL url = new URL(sURL); 6o't3Peh  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); U4D7@KY +m  
httpConnection.setRequestProperty("User-Agent","NetFox"); rH@Rh}#yp  
String sProperty = "bytes="+nStartPos+"-"; \8vP"Kr  
httpConnection.setRequestProperty("RANGE",sProperty); a4Q@sn;]  
Utility.log(sProperty); }(EH5jZ'  
!fOPYgAGKn  
epy2}TI  
InputStream input = httpConnection.getInputStream(); zsL@0]e&  
//logResponseHead(httpConnection); D|uvgu2  
GppCrQ%Ra|  
,\4]uZ<  
byte[] b = new byte[1024]; c_8&4  
int nRead; <WXVUEea  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) x,B] J4  
{ 'uL4ezTtA  
nStartPos += fileAccessI.write(b,0,nRead); (x=$b(I  
//if(nThreadID == 1) 7KC>?F  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); HuhQ|~C+~  
} \Y P,}_ ~  
E7Lqa S  
gV_v5sk  
Utility.log("Thread " + nThreadID + " is over!"); jn(x-fj6R  
bDownOver = true; c 1YDln  
//nPos = fileAccessI.write (b,0,nRead); "@Vyc6L  
} *22Vc2[i;  
catch(Exception e){e.printStackTrace ();} qO6M5g:   
} wgl<JO  
} ) Sn0Y B  
$xO8?  
m:@y_:X0  
//打印回应的头信息 8Qvs\TY  
public void logResponseHead(HttpURLConnection con) `v*HH}aDO  
{ Wjb_H (D  
for(int i=1;;i++) Be6Yh~m  
{ rT2Njy1  
String header=con.getHeaderFieldKey(i); xo>0j#  
if(header!=null) Ho &Q }<(  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ,!orD1,'  
Utility.log(header+" : "+con.getHeaderField(header)); K%q5:9m  
else rc_m{.b  
break; M @5&.  
} ] !/  
} J0xHpe  
&@iOB #H  
nFnM9 pdMK  
public void splitterStop() ;;0'BdsL`  
{ |UTajEL  
bStop = true; o1AbB?%=  
} l=DF)#>w  
AtQ.H-8r  
$*q|}Tvl#  
} :ld~9  
{'b;lA]0  
5m8u:6kQu  
/* )/RG-L  
**FileAccess.java 4'QX1p  
*//文件访问(定位,写) uw;Sfx,s  
package NetFox; VF`!ks  
import java.io.*; fyQOF ItM  
CsZ~LQ=DB  
}c/p;<  
public class FileAccessI implements Serializable{ ';C'9k<P:  
gk6f_0?X'  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 1!z{{H;W  
RandomAccessFile oSavedFile; 'Lu<2=a~  
long nPos; eiMP:  
*yBVZD|?H  
%8*:VR  
public FileAccessI() throws IOException DY2*B"^  
{ / VYT](  
this("",0); "&6vFmr  
} ^/C\:hw  
eF+F"|1h  
'f( CN3.!  
public FileAccessI(String sName,long nPos) throws IOException X1#Ar)  
{ s~M$Wo8  
oSavedFile = new RandomAccessFile(sName,"rw"); x^ `/&+m  
this.nPos = nPos; VYG@_fd!x  
oSavedFile.seek(nPos); <6UXk[y  
} PUR,r%K`  
uu6 JZp  
|  0  
public synchronized int write(byte[] b,int nStart,int nLen) }UPC~kC+Z  
{ BUXE s0]Lv  
int n = -1; q T6y&  
try{ "OLg2O^  
oSavedFile.write(b,nStart,nLen); ?+zFa2J  
n = nLen; ^ 4`aONydl  
} 0 qS/>u*  
catch(IOException e) Wga2).j6  
{ x,gk]Cf  
e.printStackTrace (); _dKMBcl)E  
} qPDNDkjDD  
Xb"i/gfxt  
eoiz]L  
return n; 5,Fq:j)MxW  
} Skr (C5T  
r#zcl)rbU  
wAHuPQ&_Q  
} JSL&` `  
}#ink4dK:  
t3)6R(JC  
/* lOm01&^"E  
**SiteInfoBean.java H_&to3b(  
*/ MG?,,8sO  
package NetFox; m)A:w.o  
;@Zuet  
0YiTv;mq;  
public class SiteInfoBean { \Oq2{S x\  
;EBKzB  
{o~TbnC  
private String sSiteURL; //Site's URL B $u/n  
private String sFilePath; //Saved File's Path _=HaE&  
private String sFileName; //Saved File's Name |dR}S!fmG  
private int nSplitter; //Count of Splited Downloading File 3Q,&D'];[  
k8?._1t  
z"f@iJX?2  
public SiteInfoBean() U'=8:&  
{//nSplitter的缺省值为5 h$8h@2%  
//default value of nSplitter is 5 6{6hz 8  
this("","","",5); ;"M6}5dQ4  
} d88A.Z3w  
t oGiG|L  
w[X-Q+7p(t  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) }u;K<<h:  
{ x,C8):\t`B  
sSiteURL= sURL; LK}g<!o(  
sFilePath = sPath; 2E1`r@L  
sFileName = sName; f2e;N[D  
this.nSplitter = nSpiltter; D$>!vD'  
t=B1yvE "  
I8XP`Ccq  
} ^6 wWv&G[8  
sU>IETo  
,zgz7  
public String getSSiteURL() ,sitOy}ks  
{ o< @![P  
return sSiteURL; rd7p$e=i  
} -Cyo2wk  
xt}.0dC!/%  
O}i+ 1  
public void setSSiteURL(String value) ,IB\1#  
{ LDQ,SS,  
sSiteURL = value; u\ _yjv#  
} e|oMbTZ5m  
{D[6=\ F  
k9%o{Uzy  
public String getSFilePath() >ZJ]yhbhK  
{ 8&U Mmbgy  
return sFilePath; 0si1:+t-[+  
} Mp/l*"(  
X,G<D}  
NK qI x  
public void setSFilePath(String value) 4s 7 RB  
{ wQG?)aaM  
sFilePath = value; ,ayEZ#4.m  
} =mXC,<]  
$wAR cS  
Ba[,9l[  
public String getSFileName() W yM1s+@  
{ - VJx)g  
return sFileName; =803rNe  
} vCP[7KhGj  
qb[hKp5K6  
L2>e@p\>  
public void setSFileName(String value) |Y K,&  
{ &{e ]S!D  
sFileName = value; ulxlh8=  
} U;W9`JT<.f  
lU doMm  
WkXgz6 P  
public int getNSplitter() _tHhS@   
{ Mz&/.A  
return nSplitter; X$5  
} ( unmf,y  
/ <)Vd  
KRL.TLgq)  
public void setNSplitter(int nCount) X&WP.n)  
{ Z5Lmg  
nSplitter = nCount; fHd[8{;P:  
} :|n[zjK/S  
} 9)7$UQY  
2VRGTx  
`h@fW- r  
/* di/Q Jrw  
**Utility.java ;mEn@@{  
*/ 2{?]W/&fS  
package NetFox; Dizz ?O  
42]7N3:'  
`rVru= zoy  
public class Utility { E[t0b5h  
s $Vv  
N" L&Z4Z  
public Utility() 9nN1f@Y  
{ 36{GZDGQ  
>[Vc$[62  
;p+'?%Y}  
} To(I<W|{  
:\|A.# U  
//线程睡眠 V<UChD)N`  
public static void sleep(int nSecond) J'Pyn  
{ vS\2zwb}  
try{ yD~,+}0)  
Thread.sleep(nSecond); <-k!  
} C7S\4rDJ  
catch(Exception e) ,40OCd!  
{ ],SQD3~9  
e.printStackTrace (); Ysu\CZGX  
} '$OUe {j<  
} 3A`Gx#  
YTyrX  
//日志 ^m%#1Zd  
public static void log(String sMsg) Uuy$F  
{ 0S4BV%7F  
System.err.println(sMsg); R1H^CJ=v0  
} *#YZm>h   
U1r]e%df)  
rD=D.1_   
public static void log(int sMsg) 5Rl\& G\  
{ (|BY<Ac3  
System.err.println(sMsg); ULAr!  
} qf(mJlU  
} KZjh<sjX|  
zzZ EX  
,*iA38d.!  
/* -~{Z*1`,  
**TestMethod.java nq{/fD(2  
*/ 6|NH*#s  
package NetFox; n.+'9Fj  
es*$/A  
\o!3TK"N  
public class TestMethod { [@Ac#  
.j:,WF<"l5  
-!XG>Z  
public TestMethod() dQ8RrD=$&  
{ ///xx/weblogic60b2_win.exe hty'L61\z  
try{ Q!P%duO  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); &DMC\R*j  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 59oTU  
SiteFileFetch fileFetch = new SiteFileFetch(bean); NVb}uH*i  
fileFetch.start(); A5Hx $.Z  
} k K=VG< :M  
catch(Exception e){e.printStackTrace ();} $YX{gk>  
;NA5G:eQ  
VwI  
}  Gk~aTO  
K(?V]Mxl6  
9;L4\  
public static void main(String[] args) WPRk>j  
{ @SD XJJ h  
new TestMethod(); "0!h- bQN  
} 9:{<:1?  
} 5$ =[x!x  
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