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http断点续传简单实现(java)

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/* D30Z9_^%:  
**SiteFileFetch.java 0~L 8yMM  
*/ U!UX"r  
package NetFox; qx CL  
import java.io.*; 2dJ)4  
import java.net.*; .1q~,}toX  
DBrzw+;e3  
S$_Ts1Ge6  
public class SiteFileFetch extends Thread { -clg 'Aa;.  
N*)8L[7_;  
\]:NOmI^'  
SiteInfoBean siteInfoBean = null; //文件信息Bean ghd[G}  
long[] nStartPos; //开始位置 q>lkLHS  
long[] nEndPos; //结束位置 C]cT*B^  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 a ZCZ/  
long nFileLength; //文件长度 5N</Z6f'o  
boolean bFirst = true; //是否第一次取文件 n)7$xYuH  
boolean bStop = false; //停止标志 ]be2jQx3  
File tmpFile; //文件下载的临时信息 \c^jaK5  
DataOutputStream output; //输出到文件的输出流 O NzdCgY  
kk./-G  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) X!HSS/'  
public SiteFileFetch(SiteInfoBean bean) throws IOException ^>}[[:(6/  
{ [67f;?b  
siteInfoBean = bean; hr"+0KeX  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ZjbG&oc  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); XlcDF|?{.  
if(tmpFile.exists ()) Evgq}3  
{ _I"<?sh 3  
bFirst = false; <y/AEY1  
read_nPos(); T1W9@9,s  
} vh.tk^&  
else "YU~QOGx@  
{ ^9~%=k=  
nStartPos = new long[bean.getNSplitter()]; @9P9U`ZP  
nEndPos = new long[bean.getNSplitter()]; )s[S.`S Tz  
} ] Lft^,7  
y/*Tvb #TJ  
=@/^1.`  
[*E.G~IS`  
} wbKBwI5w  
~l(tl[  
BJ2W }R  
public void run() oa|*-nw  
{ ' "p*FN  
//获得文件长度 |Dpfh  
//分割文件 otVdx&%]  
//实例FileSplitterFetch 8pt<)Rs}  
//启动FileSplitterFetch线程 FQRcZpv;  
//等待子线程返回 MM$" 6Jor  
try{ :@'0)7  
if(bFirst) qCT\rZU  
{ _( /lBf{|  
nFileLength = getFileSize(); \5c -L_  
if(nFileLength == -1) $=a$z"  
{ +W[#;)ea(  
System.err.println("File Length is not known!"); jJC( (1|  
} JT_B@TO\  
else if(nFileLength == -2) $d[:4h~  
{ lD=j/    
System.err.println("File is not access!"); A{"t0Ai='0  
} 9 9BK/>R  
else q)y8Bv|  
{ mV]g5>Q\  
for(int i=0;i<nStartPos.length;i++) [:'?}p  
{ \`5u@Nzx  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); J~`%Nj5>  
} $F$R4?_  
for(int i=0;i<nEndPos.length-1;i++) N2Hb19/k  
{ \`# 0,pLr  
nEndPos = nStartPos[i+1]; HBGA lZ  
} ?2>v5p  
nEndPos[nEndPos.length-1] = nFileLength; .Sw'Bo!Ee  
} =xP{f<`   
} .Q@'Ob`  
zhL,BTH  
?E@[~qq_  
//启动子线程 6;V 1PK>9  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; &h[}5  
for(int i=0;i<nStartPos.length;i++) p[:%Ck"$7  
{ ^Pp FI  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), BVeNK=7m%  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), }-iOYSn  
nStartPos,nEndPos,i); kfECC&"  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ]`9K|v  
fileSplitterFetch.start(); DMW:%h{  
} (fb\A6  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), h%e!f#  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); BBj"}~da  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", C{^@.8:  
nEndPos = " + nFileLength); iP_Xr~w  
// fileSplitterFetch[nPos.length-1].start(); z5w|+9U  
.q}k  
%W@IB8]Vr  
//等待子线程结束 S3wH M  
//int count = 0; YNk|UwJi  
//是否结束while循环 ZM!~M>B9R  
boolean breakWhile = false; uMZf9XUE  
W<l(C!{  
brot&S2P><  
while(!bStop) T6#GlO)8)  
{ 11+_OC2-   
write_nPos(); [)u{-  
Utility.sleep(500); :E*U*#h/  
breakWhile = true; NWj@iyi<  
C =U4|h~W  
KHiJOeLc  
for(int i=0;i<nStartPos.length;i++) OO>2oH  
{ pBLO  
if(!fileSplitterFetch.bDownOver) *?Y6qalSy  
{ 7^5BnF@  
breakWhile = false; ;O>fy :$'  
break; 5,Zn$zosJC  
} WQ`T'k#ESW  
} i(rY'o2 BN  
if(breakWhile) net9K X4\  
break; px@\b]/  
H:6$) #  
`h6W@ROb  
//count++; INpub 5  
//if(count>4) 49GCj`As  
// siteStop(); m"]ys #  
} 3J<,2  
{Wo7=aR  
1fZ:^|\  
System.err.println("文件下载结束!"); 1YL5 ![T  
} bux-t3g7+  
catch(Exception e){e.printStackTrace ();} L;`t%1  
} J K^;-&  
Y1IlH8+0  
O2f2Fb$B7  
//获得文件长度 fO nvC*  
public long getFileSize() ;wrgpP3  
{ Jmx }r,j  
int nFileLength = -1; lX3h'h  
try{ |e >-v  
URL url = new URL(siteInfoBean.getSSiteURL()); pM3BBF%  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 2oLa`33c1  
httpConnection.setRequestProperty("User-Agent","NetFox"); |&7,g  
oJ:J'$W(  
= ;d<Ikj  
int responseCode=httpConnection.getResponseCode(); L4b4X  
if(responseCode>=400) g!ww;_  
{ cK&oC$[r-  
processErrorCode(responseCode); = @o}  
return -2; //-2 represent access is error %\0 Y1!Hw  
} KHtY +93  
AAcbY;  
|#6Lcz7[  
String sHeader; P_U-R%f  
.<dmdqk]  
4^&vRD,  
for(int i=1;;i++) ev $eM  
{ 5>Q)8` @E  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); u7d]%<~'$F  
//Utility.log(in.readLine()); {,=,0NQKn  
sHeader=httpConnection.getHeaderFieldKey(i); `>Cx!sYhV  
if(sHeader!=null) >^&+,*tsS4  
{ r8rR_ M{P  
if(sHeader.equals("Content-Length")) oV`sCr5%  
{ T!bu}KO  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); se[};t:  
break; m@ YL Z  
} r;z A `  
} "RLb wm~  
else -w B AFr  
break; o*_D  
} {QID@  
} nKdLhCN'=  
catch(IOException e){e.printStackTrace ();} Q1z04m1_y[  
catch(Exception e){e.printStackTrace ();} yhaYlYv[_3  
oWmla*nCKL  
j7&l&)5  
Utility.log(nFileLength); {Y Ymt!Ic  
+zsya4r  
q]x@q  
return nFileLength; uc_ X;M;  
} MXb(Z9)]kw  
|k+^D:  
pC6_ jIZ  
//保存下载信息(文件指针位置) JN_# [S$  
private void write_nPos() o9i\[Ul  
{ GSp1,E2J  
try{ e 3K  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 8T4J^6  
output.writeInt(nStartPos.length); PJ{.jWwD  
for(int i=0;i<nStartPos.length;i++) !_@%/I6  
{ ~"k'T9QBY  
// output.writeLong(nPos); D6w0Y:A{.  
output.writeLong(fileSplitterFetch.nStartPos); 7nmo p7  
output.writeLong(fileSplitterFetch.nEndPos); z( wXs&z;  
} {/ta1&xyG  
output.close(); '' 6  
} ]NCOi ?Odx  
catch(IOException e){e.printStackTrace ();} F~1R.r_Lu  
catch(Exception e){e.printStackTrace ();} scdT/|(U$  
} E _K7.c4M  
:R)IaJ6)  
DI_mF#5q  
//读取保存的下载信息(文件指针位置) amRtFrc|  
private void read_nPos() W4<}w-AoEp  
{ a|.u;  
try{ )-(NL!?`  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); o0 Ae*Y0  
int nCount = input.readInt(); <  -Nj  
nStartPos = new long[nCount]; l _:%?4MA  
nEndPos = new long[nCount]; )7^jq|  
for(int i=0;i<nStartPos.length;i++) &kG<LGXP#  
{ -Q; w4@  
nStartPos = input.readLong(); {-xnBx  
nEndPos = input.readLong(); U^xFqJY6  
} L$g;^@j  
input.close(); pfT7  
} (I$hw"%&  
catch(IOException e){e.printStackTrace ();} :O7J9K|  
catch(Exception e){e.printStackTrace ();} 6XP>p$-  
} tVOx  
$[Fk>d  
.NKN2  
private void processErrorCode(int nErrorCode) !>Xx</iD1  
{ Y3[@(  
System.err.println("Error Code : " + nErrorCode); + '`RJ,K+[  
} CVm*Q[5s"  
R:Lu)d>=  
4T:ZEvdzf  
//停止文件下载 4Xz|HU?  
public void siteStop() <*[(t;i  
{ %X3T<3<  
bStop = true; MYjCxy-;A  
for(int i=0;i<nStartPos.length;i++) O%Mh g\#B  
fileSplitterFetch.splitterStop(); n3(HA  
&\LbajP:+  
tm$3ZzP4  
} .MKxHM7  
} Fq8Z:;C8  
//负责部分文件的抓取 1W U-gQki!  
**FileSplitterFetch.java y3x_B@}BY  
*/ <%5ny!]  
package NetFox; M<SZ7^9<  
q bo`E!K  
@c.pOX[]m,  
import java.io.*; %lBFj/B  
import java.net.*; VD4(  
x-[l`k.V  
!59q@M ya[  
public class FileSplitterFetch extends Thread { ZR1EtvVG  
6Pz\6DU,I  
U-@\V1;C  
String sURL; //File URL fIu/*PFPVY  
long nStartPos; //File Snippet Start Position uB\A8zC  
long nEndPos; //File Snippet End Position o\N),;LM  
int nThreadID; //Thread's ID k20tn ew  
boolean bDownOver = false; //Downing is over |K]tJi4fz  
boolean bStop = false; //Stop identical y0 xte&  
FileAccessI fileAccessI = null; //File Access interface >">-4L17m  
139_\=5|U/  
^Oo%`(D?  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException qg_=5s  
{ /wQDcz  
this.sURL = sURL; {J[0UZ6  
this.nStartPos = nStart; #(%6urd  
this.nEndPos = nEnd; QgP UP[  
nThreadID = id; ~!I \{(  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Z',pQ{rD  
} y&UsSS  
7Xa Ri@uG  
&a V`u?'e  
public void run() TV}H  
{ WkT4&|POJ  
while(nStartPos < nEndPos && !bStop) ;e+ErN`a.~  
{ )Ipa5i>t  
$(BW |Pc  
DUaj]V{_^  
try{ KyjN'F$  
URL url = new URL(sURL); Kg 56.$  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &Mol8=V)  
httpConnection.setRequestProperty("User-Agent","NetFox"); q:fkF^>  
String sProperty = "bytes="+nStartPos+"-"; YQ]W<0(  
httpConnection.setRequestProperty("RANGE",sProperty); env]*gx+=  
Utility.log(sProperty); jVr:O `  
=m UtBD.;  
/)j:Y:5  
InputStream input = httpConnection.getInputStream(); {a(TT)d  
//logResponseHead(httpConnection); $. Ih-  
eKt~pzXwm  
PAJt M  
byte[] b = new byte[1024]; %5'6^bT  
int nRead; tks1*I$S<  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) &4LrV+`$V  
{ Uo# Pe@ieQ  
nStartPos += fileAccessI.write(b,0,nRead); @,$>H 7o  
//if(nThreadID == 1) Esd A %`  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); d4~!d>{n|c  
} yN9/'c~  
Mp}U>+8  
up1kg>i%"  
Utility.log("Thread " + nThreadID + " is over!"); t\ ym4`"  
bDownOver = true; s~3"*,3@  
//nPos = fileAccessI.write (b,0,nRead); 'bTtdFvJ  
} q>t#5Z81  
catch(Exception e){e.printStackTrace ();} b}WU  
} @u?m4v{  
} qeypa !  
+Y-Gp4"  
r3'0{Nn+  
//打印回应的头信息 8 K'3iw>z  
public void logResponseHead(HttpURLConnection con) G@s rQum(  
{ `#R[x7bA1  
for(int i=1;;i++) 09/Mg  
{ `KB;3L  
String header=con.getHeaderFieldKey(i);  tmKHT  
if(header!=null) #mFIZMTRd  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); J.$N<.  
Utility.log(header+" : "+con.getHeaderField(header)); EjrK.|I0  
else W|4:3 c4  
break; ;O+= 6>W  
} nH_M#  
} qf;x~1efC4  
2)-Umq{]{  
|cs]98FEf  
public void splitterStop() 9!; /+P  
{ @P@?KZ..v!  
bStop = true; PKJw%.-  
} dSkMA  
}"Clv /3_  
Qu|H_<8g  
} ;0FfP  
,N93H3(  
$i1$nc8  
/* wNtC5  
**FileAccess.java -%,=%FBi~4  
*//文件访问(定位,写) yw\Q>~$n[=  
package NetFox; {OIB/  
import java.io.*; =bgWUu\F  
.~u[rc|<  
DHQS7%)f`  
public class FileAccessI implements Serializable{ xa8;"Y~"bg  
VYbH:4K@%  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ^,}1^?*  
RandomAccessFile oSavedFile; zcGmru|k  
long nPos; TophV}@B`  
zncKd{Q\tP  
u.;l=tzz  
public FileAccessI() throws IOException VkFMr8@|  
{ cDS \=Bf  
this("",0); u:.w/k%+  
} -Gy=1W`09  
>e^bq/'  
6 dgwsl~  
public FileAccessI(String sName,long nPos) throws IOException y*=sboX  
{ 7vTzY%v  
oSavedFile = new RandomAccessFile(sName,"rw"); HA$X g j  
this.nPos = nPos; %:t! u&:q  
oSavedFile.seek(nPos); j<'ftK k  
} A*G ~#v^  
,<k%'a!B  
1%ENgb:8  
public synchronized int write(byte[] b,int nStart,int nLen) L+N\B@ 0-  
{ M0yv= g  
int n = -1; w p\-LO~  
try{ Q p7h|<  
oSavedFile.write(b,nStart,nLen); 1J([*)  
n = nLen; {8>g?4Q#  
} D6-R>"}  
catch(IOException e) >dx/k)~~-L  
{ `*6|2  
e.printStackTrace (); [;H-HpBaa  
} kM J}sS  
$GP66Ev  
60;_^v  
return n; ,p{naT%R  
} Dj>eAO>  
djH&)&q!  
}y Vx"e)  
} .' }jd#  
O uNPDq%  
?r 0rY?  
/* `WIZY33V  
**SiteInfoBean.java 63'm @oZ  
*/ 9#TD1B/  
package NetFox; @R%* ;)*F  
tn#cVB3  
fLnwA|n=  
public class SiteInfoBean { 3Q'vVNFh<  
l^Ob60)2  
|.VSw  
private String sSiteURL; //Site's URL ^s6}[LDW>@  
private String sFilePath; //Saved File's Path }4N'as/ZO  
private String sFileName; //Saved File's Name 8OKG@hc  
private int nSplitter; //Count of Splited Downloading File qg{gCG  
^D<CoxG  
L&c & <+0T  
public SiteInfoBean() :.4O Hp1  
{//nSplitter的缺省值为5 T%% 0W J  
//default value of nSplitter is 5 9dq"x[  
this("","","",5); }4p)UX>aWT  
} Li]bU   
]!ox2m_U  
VwpC UW  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) n&Ckfo_D  
{ f`:GjA,J$  
sSiteURL= sURL; -w*fS,O  
sFilePath = sPath; U$mDAi$  
sFileName = sName; hw,nA2w\  
this.nSplitter = nSpiltter; Vm|KL3}NRv  
G<M0KU (  
hs[x\:})/  
} y_X jY  
aX`uF<c9  
V:w%5'^3  
public String getSSiteURL() +}O -WX?  
{ 9 wZ?")2  
return sSiteURL; -=nk,cYn  
} 5CZyA`3V^5  
]Cj@",/3#  
;Ax-f04gG  
public void setSSiteURL(String value) \o}T0YX  
{ Asv]2> x  
sSiteURL = value; Ly&+m+Gwu  
} ?<${?L>  
)i}j\";>L  
OL>)SJj5  
public String getSFilePath() Qn7T{ BW  
{ '{cSWa| #  
return sFilePath; Rjq Xz6  
} ._^}M<o L  
0W(mx-[H/  
 ][wb4$2  
public void setSFilePath(String value) ]R_R`X?  
{ rw,Ylr :3  
sFilePath = value; ])wdd>'  
} @>HTbs6W  
i+h*<){X  
*mzi ?3  
public String getSFileName() <a]i"s  
{ db~^Gqv6k  
return sFileName; 5>I-? Ki  
} JcWp14~e  
4d`YZNvZW/  
:ZM9lBYh  
public void setSFileName(String value) uX*2Rs$s  
{ 4~,Z 'k  
sFileName = value; d #1Y^3n  
} H"FK(N\  
sqrLys_S  
l::q F 0  
public int getNSplitter() QQBh)5F  
{ QkBw59L7  
return nSplitter; . :Skc  
} g%&E~V/g$  
-NXxxK  
!HvA5'|:}  
public void setNSplitter(int nCount) iX$G($[l(  
{ G IN|cv=  
nSplitter = nCount; #B;P4n3  
} P9/ (f$=  
} ^+SE_-+]  
7q+D}+ Xf  
fZ$b8  
/* T&lgWOls  
**Utility.java TI'v /=;)  
*/ =vbG'_[7  
package NetFox; 053bM)qW  
QWk3y"5n<  
YIg(^>sq  
public class Utility { cD0rU8x  
{Sf[<I  
:~otzI4%!  
public Utility() LqbI/AQ)  
{ vkIIuNdDlx  
&"^F;z/  
Ca|egQv  
} E+aePoU  
?H=q!i  
//线程睡眠 L}`/v]E"eU  
public static void sleep(int nSecond) Am<5J,<uy  
{ xU.1GI%UPu  
try{ fzIs^(:fl  
Thread.sleep(nSecond); ; ~pgF_  
} YNr"]SA@;  
catch(Exception e) B&]`OO>O  
{ M7TLQqaF  
e.printStackTrace (); 2!{D~Gfl=  
} !;eE7xn&  
} ZwkUd-=0i  
Cz0FA]-g  
//日志 Ix-Mp   
public static void log(String sMsg) J8 qFdNK  
{ XwY,xg&o  
System.err.println(sMsg); N&HI)X2&  
} >v]^nJl  
iH8we,s'  
wXIRn?z  
public static void log(int sMsg) B*T n@t W  
{ jH< #)R  
System.err.println(sMsg); 1&|]8=pG7  
} {DRk{>K,  
} *?FVLE  
V|8'3=Z=  
UxGu1a  
/* (BEe^]f  
**TestMethod.java YvJFZ_faX  
*/ j'D%eQI,V  
package NetFox; WXy8<?s  
~*HQPp?v  
w"j>^#8  
public class TestMethod { |V a:*3u  
~CNB3r5R  
@G4Z  
public TestMethod() ], lLD UZ\  
{ ///xx/weblogic60b2_win.exe C%z)D1-  
try{ #`VAw ) eV  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); "w:h  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); !"N,w9MbD  
SiteFileFetch fileFetch = new SiteFileFetch(bean); B[N]=V  
fileFetch.start(); 2lTt  
} }J#HIE\RG  
catch(Exception e){e.printStackTrace ();} _4by3?<c  
zjmo IE  
cYA:k  
} e$[O J<t  
, Y:oTo=~  
,Kv6!ib6Q  
public static void main(String[] args) # EvRm  
{ $|~ <6A{y  
new TestMethod(); uj8saNu  
} 287j,'vR  
} ^B<-.(F  
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