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http断点续传简单实现(java)

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/* kK_>*iCMo  
**SiteFileFetch.java e^ K=8IW  
*/ A&@jA5Jb  
package NetFox; ;/]c^y  
import java.io.*; u9[w~U#  
import java.net.*; 1OJD\wc  
ok W)s*7  
6CzvRvA*P  
public class SiteFileFetch extends Thread { ,J4a~fPf  
-a#AE|`  
+[go7A$5  
SiteInfoBean siteInfoBean = null; //文件信息Bean j^R~ Lt4  
long[] nStartPos; //开始位置 W(3~F2  
long[] nEndPos; //结束位置 e?'k[ES^  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 . LVOaxT  
long nFileLength; //文件长度 -2m Ogv  
boolean bFirst = true; //是否第一次取文件 F$pd]F!#  
boolean bStop = false; //停止标志 & m ";D  
File tmpFile; //文件下载的临时信息 -O,O<tOm  
DataOutputStream output; //输出到文件的输出流 eWt>^]H~  
E*#60z7F  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) g\mrRZ/?  
public SiteFileFetch(SiteInfoBean bean) throws IOException SGT-B.  
{ "}Sid+)<  
siteInfoBean = bean; */@bNT9BgO  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); XVK[p=cIL  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); c`[uQXv  
if(tmpFile.exists ()) (/UMi,Ho  
{ ?. 'oxW  
bFirst = false; LZ<( :S  
read_nPos(); `oI/;&  
} #esu@kMU`  
else F[qI fh4  
{ ^bgm0,M  
nStartPos = new long[bean.getNSplitter()]; *d*;M>  
nEndPos = new long[bean.getNSplitter()]; nJ`a1L{N  
} V,%5 hl'&  
%)@(T ye -  
7]+'%Uwu)  
t~=@r9`S  
} IF21T  
G6g=F+X2  
"I 1M$^8n  
public void run() d}G."wnG9,  
{ 6je%LHhL  
//获得文件长度 BN> $LL  
//分割文件 AG!a=ufc0  
//实例FileSplitterFetch \7?MUa.4  
//启动FileSplitterFetch线程 AZ@Zo'  
//等待子线程返回 Bwvc@(3v  
try{ [Z&s0f1Qb  
if(bFirst) |gxB; GG  
{ kj"_Y"q=  
nFileLength = getFileSize(); WX$^[^=HC  
if(nFileLength == -1) 544I#!  
{ u+T, n  
System.err.println("File Length is not known!"); SCC/ <o  
} $ }bC$?^  
else if(nFileLength == -2) _|#|mb4Fe  
{ \.-y LS.  
System.err.println("File is not access!"); FbT&w4Um=  
} ].+G-<.:  
else F n Rxc  
{ _ r)hr7  
for(int i=0;i<nStartPos.length;i++) ,,-3p#P bw  
{ p{QKj3ov  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); u>Kvub  
} "k@/Z7=  
for(int i=0;i<nEndPos.length-1;i++) J A2}  
{ ^bw~$*"j#  
nEndPos = nStartPos[i+1]; w%u[~T7OI  
} Sgk{NM7|k  
nEndPos[nEndPos.length-1] = nFileLength; %R5MAs&-5  
} -]MP,P%  
} tm#y `1-  
 JS.' v7  
0-O.*Q^  
//启动子线程 2xxwQwg8  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; \O4=mJ  
for(int i=0;i<nStartPos.length;i++) n;Wf|>  
{ {oC69n:  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), K#yH\fn8  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), R')GQ.yYq  
nStartPos,nEndPos,i); +*~3"ww<  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 87*[o  
fileSplitterFetch.start(); `Wt~6D e  
} Z ' 96d  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), J(*"S!q)6  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); s'w 0pZqj  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 7oSuLo=  
nEndPos = " + nFileLength); ?2/M W27w  
// fileSplitterFetch[nPos.length-1].start(); Bd[}A9O[  
`Hu ;Gdj=  
M|u5Vs1  
//等待子线程结束 ?5M2DLh~  
//int count = 0; `-\JjMSQ1  
//是否结束while循环 \Vq;j 1  
boolean breakWhile = false; `215Llzk;  
he6) L6T  
Ct33S+y  
while(!bStop) j;vaNg|vQ  
{ 5~5ypQj  
write_nPos(); I[Y?f8gJ  
Utility.sleep(500); t;6/bT-  
breakWhile = true; >b${rgCvQ  
tq93 2M4  
M_uij$1-  
for(int i=0;i<nStartPos.length;i++) #&gy@!a~  
{ t:n|0G(  
if(!fileSplitterFetch.bDownOver) OOwJ3I >]>  
{ q+Q)IVaU81  
breakWhile = false; ,g.=vQm:?  
break; Q:=/d$*xd  
} k9?+9bExXA  
} 40ZB;j$l  
if(breakWhile) c *noH[  
break; arrcHf 4O  
o%7yhCY  
?2Dz1#%D  
//count++; Kj5f:{Ur  
//if(count>4) *a@UV%u  
// siteStop(); )9,"~P2[R  
} 9_$Odc%]  
`Nr7N#g+u  
Qgi:q  
System.err.println("文件下载结束!"); "+_0idpF  
} tx-bzLo\  
catch(Exception e){e.printStackTrace ();} osI(g'Xb  
} )2hoO_l:  
m#p^'}]!;  
D.f=!rT7E7  
//获得文件长度 wxrT(x|  
public long getFileSize() Reo0ZU>  
{ wtyu"=  
int nFileLength = -1; e2F7G>q:5  
try{ sP!qv"u  
URL url = new URL(siteInfoBean.getSSiteURL()); @x4Dt&:"  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); E$ rSrT(  
httpConnection.setRequestProperty("User-Agent","NetFox"); W,+91rup  
Q0q$ZK6C  
0:p#%Nvg  
int responseCode=httpConnection.getResponseCode(); n!nv.-n  
if(responseCode>=400) } U.B$4Q  
{ L1BpY-=  
processErrorCode(responseCode); 'z:p8"h}  
return -2; //-2 represent access is error b.+\qaR  
} .(ir2g  
ya=51~ by"  
I'hQbLlG  
String sHeader; `$HO`d@0*R  
%cL:*D4oz  
TMBdneS-s  
for(int i=1;;i++) /0(KKZ)  
{ RB!E>]   
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); L&%iY7sC`  
//Utility.log(in.readLine()); HVp aVM  
sHeader=httpConnection.getHeaderFieldKey(i); 6h%(0=^  
if(sHeader!=null) N0f}q1S<-A  
{ \8ZNXCP  
if(sHeader.equals("Content-Length")) &9>d  
{ m`cG&Ar5  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); <}%*4mv  
break; DSp@  
} cCIEG e6  
} mLO6`]p{H  
else tK*f8X+q  
break; ^=j$~*(LmX  
} lVHJ}(<'p  
} WP9=@X Z  
catch(IOException e){e.printStackTrace ();} :C5N(x  
catch(Exception e){e.printStackTrace ();} 7_,X9^z  
crQuoOl7  
eNX-2S  
Utility.log(nFileLength); 5l#)tX.by  
S6 *dp68  
Wu(GC]lTG  
return nFileLength; tti.-  
} FgxQ}VvlH  
0Qz \"gr  
p*Cbe\  
//保存下载信息(文件指针位置) U<x3=P  
private void write_nPos() 9viC3bj.o  
{ "rtmDNpL  
try{ 5h&8!!$[  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ;A_QI>>  
output.writeInt(nStartPos.length); z; +x`i.  
for(int i=0;i<nStartPos.length;i++) smggr{-  
{ tP9}:gu  
// output.writeLong(nPos); ?a% u=G  
output.writeLong(fileSplitterFetch.nStartPos); ?(z3/ "g]  
output.writeLong(fileSplitterFetch.nEndPos); _kS us  
} lz>hP  
output.close(); ej~ /sO  
} #R$!|  
catch(IOException e){e.printStackTrace ();} `Cc<K8s8  
catch(Exception e){e.printStackTrace ();} VQyDd~Za  
} uB BE!w_  
G+ToZ&f@  
e=U7w7(s9  
//读取保存的下载信息(文件指针位置) Yi:+,-Fso  
private void read_nPos() qXW 5_iX  
{ P;GUGG*W  
try{ tF 4"28"h  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); N.]8qzW  
int nCount = input.readInt(); eL.S="  
nStartPos = new long[nCount]; :3k(=^%G!  
nEndPos = new long[nCount]; ][Kj^7/  
for(int i=0;i<nStartPos.length;i++) M1:m"#=  
{ {,m!%FDL  
nStartPos = input.readLong(); L_(|5#IDw  
nEndPos = input.readLong(); .3[YOM7h  
} |b@-1  
input.close(); KM6r}CDHs  
} .._wTOSq  
catch(IOException e){e.printStackTrace ();} B*{CcQ<5  
catch(Exception e){e.printStackTrace ();} KQk;:1hW  
} $ _zdjzT  
+#O?sI#  
ppxu\a  
private void processErrorCode(int nErrorCode) I<$lpU_H  
{ B}vI<?c  
System.err.println("Error Code : " + nErrorCode); q8U]Hyp(`  
} 1t6UI4U!$  
X- zg  
_.j KcDf  
//停止文件下载  j%lW+ [%  
public void siteStop() B=f{`rM)~W  
{ o_cj-  
bStop = true; qVf~\H@  
for(int i=0;i<nStartPos.length;i++) rl4-nA  
fileSplitterFetch.splitterStop(); _z_uz \#,  
!cfn%+0  
n[<Vj1n  
} {d) +a$qj  
} {2,V3*NF  
//负责部分文件的抓取 LWY`J0/  
**FileSplitterFetch.java MSA*XDnN  
*/ M/BBNT  
package NetFox; O!a5  
bz@4obRqf  
? O.&=im_  
import java.io.*; :U~[%]  
import java.net.*; {pVD`#Tl[  
*w!H -*`  
9 eP @}C6  
public class FileSplitterFetch extends Thread { +s`n]1HC  
[hs{{II  
rVkHo*Q  
String sURL; //File URL kWWb<WRW:  
long nStartPos; //File Snippet Start Position hI"I#(*jA%  
long nEndPos; //File Snippet End Position s3q65%D  
int nThreadID; //Thread's ID _:{XL c  
boolean bDownOver = false; //Downing is over N-suBRnW  
boolean bStop = false; //Stop identical q*2ljcb55  
FileAccessI fileAccessI = null; //File Access interface il*bsnwpZv  
9khD7v   
sx6` g;  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ='~C$%  
{ L./UgeZ  
this.sURL = sURL; MVV<&jho{^  
this.nStartPos = nStart; Zcc6E2  
this.nEndPos = nEnd; xX}vx hN  
nThreadID = id; IKpNc+;p  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 67d0JQTu  
} &D/_@\ 0  
<.Pr+g  
0%vXPlfnY  
public void run() $"sf%{~  
{ <jV_J+#  
while(nStartPos < nEndPos && !bStop) KnlVZn[3t  
{ /<GygRs  
.Emw;+>  
.t\5H<z  
try{ 4%B${zP(.}  
URL url = new URL(sURL); #[IQmU23  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); zc(- dMlK  
httpConnection.setRequestProperty("User-Agent","NetFox"); t0/fF'GZD  
String sProperty = "bytes="+nStartPos+"-"; sURHj&:t|  
httpConnection.setRequestProperty("RANGE",sProperty); TzVNZDQ`Jl  
Utility.log(sProperty); ^G15]Pyw  
* ,,D%L  
2&dtOyxo>  
InputStream input = httpConnection.getInputStream(); )PZ'{S  
//logResponseHead(httpConnection); e KET8v[  
0?k/vV4  
JrO2"S  
byte[] b = new byte[1024]; O GSJR`yT  
int nRead; &FGz53fd4  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) X|X6^}  
{ o: TO[  
nStartPos += fileAccessI.write(b,0,nRead); nsYS0  
//if(nThreadID == 1) V+_L9  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Dg \fjuK9  
} $$AKz\  
WnA]gyc  
^oM*f{9  
Utility.log("Thread " + nThreadID + " is over!"); +b 1lCa_  
bDownOver = true; aM~M@wS  
//nPos = fileAccessI.write (b,0,nRead); iz>a0~(K  
} wOINcEdx  
catch(Exception e){e.printStackTrace ();} haS`V  
}  s(F^P  
} a(!:a+9WOP  
A:>G:X5t  
jPhOk>m  
//打印回应的头信息 t[%9z6t  
public void logResponseHead(HttpURLConnection con) ^KmyB6Yg  
{ BT >8  
for(int i=1;;i++) Z3=t"  
{ qd"*Td  
String header=con.getHeaderFieldKey(i); P5kkaLzG  
if(header!=null) db4Ol=  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); L Ktr>u  
Utility.log(header+" : "+con.getHeaderField(header)); pz~AsF  
else )N<>L/R  
break; g;Bq#/w  
} XswEAz0=  
} (q*Za  
,:j^EDCsaJ  
oljl&tuQy  
public void splitterStop() + ,0RrD )  
{ G ? H`9*y  
bStop = true; OP{ d(~+  
} -&y{8<bu4H  
 ]Ocf %(  
a'rN&*P  
} %.[t(F  
|{<g-)  
q#F;GD  
/* DO(FG-R  
**FileAccess.java yD$rls:v<  
*//文件访问(定位,写) "3W!p+W  
package NetFox; P8piXG  
import java.io.*; PKty'}KF  
3@_je)s  
/\(0@To  
public class FileAccessI implements Serializable{ mq do@  
tNoo3&  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 /EA4-#uw  
RandomAccessFile oSavedFile; % =br-c  
long nPos;  Hi|'  
%BC*h}KGH  
GjfY   
public FileAccessI() throws IOException ?&j[Rj0pH  
{ #Q"el3P+q  
this("",0); bw ' yX  
} xLPyV&j-  
M8Q-x-7  
8S &`  
public FileAccessI(String sName,long nPos) throws IOException dq[j.Nmq  
{ JY~s-jxa  
oSavedFile = new RandomAccessFile(sName,"rw"); /)e&4.6  
this.nPos = nPos; p (:\)HP)R  
oSavedFile.seek(nPos); 8(\Az5%  
} 1ki##v[ W8  
8J7 xs6@  
]@)X3}"!  
public synchronized int write(byte[] b,int nStart,int nLen) z ~T[%RjO  
{ s-J>(|  
int n = -1; Z ~:S0HDP  
try{ Da0E)  
oSavedFile.write(b,nStart,nLen); ej]^VS7w[r  
n = nLen; !Z`~=n3bk  
} :OUNZDL  
catch(IOException e) W -8<sv$b  
{ {;=I69 X  
e.printStackTrace (); uL1e?  
} ]4@_KKP  
1}}.e^Tsfr  
#db8ur3?  
return n; @q}.BcSg  
} j_H{_Ug  
s 'u6Ep/V  
^8a,gA8.  
} ck){N?y  
?sfA/9"  
Nc ,"wA  
/* 2kp.Ljt@  
**SiteInfoBean.java kVCS FF*  
*/ |[)t4A"}  
package NetFox; =hH>]$J[  
kS%FV;9>(  
G29PdmY$<  
public class SiteInfoBean { O$V 6QJ  
pej/9{*xg(  
b54<1\&  
private String sSiteURL; //Site's URL ?kI-o0@O.  
private String sFilePath; //Saved File's Path @TdPeTw\  
private String sFileName; //Saved File's Name By]XD~gcP  
private int nSplitter; //Count of Splited Downloading File kOmTji7  
[-x~Q[  
@kenv3[Lc  
public SiteInfoBean() a]>gDDF  
{//nSplitter的缺省值为5 7<<pP  
//default value of nSplitter is 5 y{0`+/\`  
this("","","",5); h/ ?8F^C#v  
} rp6Y&3p.  
>JkQ U e  
;e_dk4_  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Ou"QUn|  
{ f<= #WV  
sSiteURL= sURL; <x,u!}5J  
sFilePath = sPath; F42r]k  
sFileName = sName; @F]6[  
this.nSplitter = nSpiltter; Cg |_ ) _w  
Oz# $x  
3;zJ\a.+  
} m"t\@f  
^/47 *vcN5  
Ek~Qp9B  
public String getSSiteURL() 2asA]sY  
{ 9x0B9&  
return sSiteURL; ( \{9W  
} r  /63  
mT <4@RrB  
YAv-5  
public void setSSiteURL(String value) E{[c8l2B  
{ mk2T   
sSiteURL = value; #I|Vyufw  
} (C={/waJ  
CkE@ Ll3Z  
zmQ V6o=k  
public String getSFilePath() UTGR{>=>  
{ OkGg4X|9  
return sFilePath; 8  k9(iS  
} @>,3l;\Zh  
{a.{x+!5I-  
d8`^;T ;}d  
public void setSFilePath(String value) [cwc}f^  
{ Oh9wBV  
sFilePath = value; B q+RFo  
} `<i|K*u  
6Xb\a^ q  
z'=*pIY5f  
public String getSFileName() $~`a,[e<  
{ =unMgX]$  
return sFileName; M7-piRnd4  
} <mjH#aSy  
gQ3Co./  
)tl=tH/$  
public void setSFileName(String value) */sVuD^b`  
{ Z#BwJHh  
sFileName = value; &F1h3q)L  
} 8W)3rD>  
}0 0mJ]H(  
7Te`#"  
public int getNSplitter() C(Ujx=G+3  
{ "(PJh\S>S  
return nSplitter; s\_-` [B0  
} \Si@t{`O  
58,_  
g6o-/A!Q3  
public void setNSplitter(int nCount) *M\Qt_[  
{ U>7"BpC  
nSplitter = nCount; hSSF]  
} 0kS[`a(}J  
} M;OY+ |uA  
zDeh#  
x tg3~/H  
/* >gM|:FG  
**Utility.java V|zzj[c  
*/ I gcVl/d  
package NetFox; IE.JIi^w  
d!7cIYVZ  
KT~J@];Fb  
public class Utility { %Ez%pT0TQ#  
O|m-Uz"+  
3.U5Each-  
public Utility() 6[,*2a8  
{ X[_w#Hwp-  
*q_ .y\D  
FKY|xG9  
} Yxz(g]  
fp|!LU  
//线程睡眠 EQ1wyKZS2g  
public static void sleep(int nSecond) GQhzQM1HS  
{ :A $%5;-kO  
try{ |C?<!6.QmV  
Thread.sleep(nSecond); <use+C2  
} 6pDb5@QjTy  
catch(Exception e) ZGK*]o =)  
{ L3lf28W  
e.printStackTrace (); G 5w:  
} QE[ETv  
} 6 DqV1'  
9Xo'U;J  
//日志 g#ubxC7t<  
public static void log(String sMsg) 34_:.QK-  
{ 8`XpcK-0  
System.err.println(sMsg); <\eHK[_*  
} +RQlMAB  
K Art4+31  
u'M \m7  
public static void log(int sMsg) pE@Q (9`b{  
{ -twV?~f  
System.err.println(sMsg); o#gb+[  
} / >c F  
} Zc(uK{3W-  
}eb}oK  
#]<j.Fc`  
/* S {gB~W  
**TestMethod.java 1.U5gW/3L  
*/ 0G ^73Z  
package NetFox; <3zA|  
<gRv7 ?V[z  
(@@t,\iF  
public class TestMethod { If>k~aL7I  
TbbtD"b?  
pYIm43r H  
public TestMethod() |1C=Ow*"  
{ ///xx/weblogic60b2_win.exe PrqN5ND  
try{ mu`h6?v  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); xU+c?OLi  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); H!mNHY_fA  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 6=A   
fileFetch.start(); L;$Gn"7~  
} Tl"GOpH\]  
catch(Exception e){e.printStackTrace ();} - `F#MN  
8$9<z  
D]n9+!Ec1f  
} sT:$:=  
5/4N  Y  
k/bY>FY2r  
public static void main(String[] args) DU(QQ53  
{ v&6I\1  
new TestMethod(); veX#K#  
} gE2k]`[j]  
} A (z lX_  
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