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http断点续传简单实现(java)

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/* Z ]ZUK  
**SiteFileFetch.java qFDy)4H)  
*/ #')] ~Xa  
package NetFox; U v>^ Z2  
import java.io.*; ! @Vj&>mH$  
import java.net.*; w^HI lA  
bOrE86v:  
bT9:9LP  
public class SiteFileFetch extends Thread { rO#$SW$YW  
y|*4XF<b  
y,Bj,zw  
SiteInfoBean siteInfoBean = null; //文件信息Bean 9"1=um=  
long[] nStartPos; //开始位置 gMq;  
long[] nEndPos; //结束位置 ,g?M[(wtc  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 0e]J2>  
long nFileLength; //文件长度 d/*EuJYin<  
boolean bFirst = true; //是否第一次取文件 {[NQD3=+F  
boolean bStop = false; //停止标志 )PU\|I0|)e  
File tmpFile; //文件下载的临时信息 6rG7/  
DataOutputStream output; //输出到文件的输出流 U:MZN[Cc[  
TQ/#  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 23p.g5hJi  
public SiteFileFetch(SiteInfoBean bean) throws IOException 5HL>2 e[  
{ a04S&ezj  
siteInfoBean = bean; {/?{UbU  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); u|EJ)dT?  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); E6G;fPd= E  
if(tmpFile.exists ()) $1)NYsSH/H  
{ Sqmjf@o$>  
bFirst = false; /Z#AHfKF  
read_nPos(); 93w$ck},?G  
} O f-gG~  
else C`3fM05g  
{ ^( C,LVP<  
nStartPos = new long[bean.getNSplitter()]; 98<^!mwF  
nEndPos = new long[bean.getNSplitter()]; c[OQo~m$  
} M5`m5qc3  
hdM?Uoo(4a  
*x 2u  
Pj8Vl)8~NV  
} }gX4dv B  
Z,XivU&  
FEa%wS{  
public void run() #^i+'Z=L  
{ cx)x="c  
//获得文件长度 +'` ^ N  
//分割文件 {=R vFA  
//实例FileSplitterFetch b_~KtMO  
//启动FileSplitterFetch线程 ' e x/IqbK  
//等待子线程返回 T[0CD'|E  
try{ l$!NEOK  
if(bFirst) =<= [E:B  
{ ]Qx-f* D6  
nFileLength = getFileSize(); G jrN1+9=  
if(nFileLength == -1) ?f:\&+.&  
{ ;%u)~3B$JK  
System.err.println("File Length is not known!"); dwzk+@]8  
} F 'HYWH0?  
else if(nFileLength == -2) 6ESS>I"su  
{ ^'sOWIzeiY  
System.err.println("File is not access!"); &j{I G`Trl  
} 'xM\txZ;  
else f%YD+Dt_V  
{ 1&kf2\S  
for(int i=0;i<nStartPos.length;i++) tE=$#  
{ !:g\Fe]  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 1tpt433  
} *(*XNd||  
for(int i=0;i<nEndPos.length-1;i++) .8|5;!`WB  
{ '+S!>Lqb  
nEndPos = nStartPos[i+1]; <@@@Pl!~  
} +w@/$datI  
nEndPos[nEndPos.length-1] = nFileLength;  _8z  
} ,(#n8|q4  
} )7rMevF(xJ  
*K=me/ 3  
R*O6Z"h  
//启动子线程 L=<,+m[!  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; u C`)?f*I  
for(int i=0;i<nStartPos.length;i++) "r{ ^Y??  
{ ,76nDXy`  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), D4GXZX8 K  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 'BEM:1)  
nStartPos,nEndPos,i); YjG:ECj}  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); T=cb:PD{%  
fileSplitterFetch.start(); :OY7y`hRG  
} Dw2$#d  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), &\r_g!Mh  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Yg`z4 U'6~  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", iJu$&u  
nEndPos = " + nFileLength); C1~Ro9si  
// fileSplitterFetch[nPos.length-1].start(); ,rQPs  
MWc{7,  
GwlAEhP  
//等待子线程结束 cFG%Ew@  
//int count = 0; K~z9b4a>  
//是否结束while循环 H*dQT y,  
boolean breakWhile = false; }KrZ6cG9#  
kI$X~s$r  
MXpj_+@  
while(!bStop) {D&:^f  
{ K:sC6|wG  
write_nPos(); 1FC 1*7A[  
Utility.sleep(500); 9hs7B!3pc>  
breakWhile = true; !1?Nc}T0Q&  
z#| tl/aP9  
(KG>lTdN  
for(int i=0;i<nStartPos.length;i++) `\S~;O  
{ uwb>q"M  
if(!fileSplitterFetch.bDownOver) u:4?$%rB  
{ PR1%  
breakWhile = false; o"A%dC_  
break; nF| m*_DW  
} P}Ule|&LK  
} 5 %aT  
if(breakWhile) R:DW>LB  
break; [k6 5i  
})r[q sv  
"PPn^{bYm  
//count++; ~ +z'pK~c  
//if(count>4) I#hzU8Cc  
// siteStop(); [5kaF"  
} <?iwi[S  
ag$UNV  
lV!@h}mG  
System.err.println("文件下载结束!"); $f<Rj/`&  
} s"]LQM1|  
catch(Exception e){e.printStackTrace ();} *gzX=*;x+?  
} 7":0CU% %  
Ib8xvzR6I&  
7:T 5P  
//获得文件长度 BI6o@d;=4  
public long getFileSize() =Wk!mGc  
{ u7<s_M3%N  
int nFileLength = -1; A@"CrVE  
try{ pfvNVu  
URL url = new URL(siteInfoBean.getSSiteURL()); /F 1mYq~  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); dmD ':1  
httpConnection.setRequestProperty("User-Agent","NetFox"); wXsA-H/`  
QFf lx  
dPRGL hWF  
int responseCode=httpConnection.getResponseCode(); 21U,!  
if(responseCode>=400) 7uRXu>h  
{ F/w!4,'<?5  
processErrorCode(responseCode); .Su9fj y%  
return -2; //-2 represent access is error G P/3r[MH  
} N8l(m5Kk,k  
';!02=-@  
 0$l D  
String sHeader; /z+}xRS  
vrIM!~*W  
Hv1d4U"qM  
for(int i=1;;i++) %k3a34P@  
{ # 1,(I  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); a4! AvG  
//Utility.log(in.readLine()); 4o2 C=?@(  
sHeader=httpConnection.getHeaderFieldKey(i); =jmn  
if(sHeader!=null) ghiFI<)VY  
{ wLC|mByq  
if(sHeader.equals("Content-Length")) rT ~qoA\  
{ x_ \e&"x  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); @cF aYI  
break; '?k*wEu  
}  B9^@]  
} _dq.hW7  
else *(x`cf;k  
break; d&0^AvM@  
} L +s,,k  
} Os1(28rl  
catch(IOException e){e.printStackTrace ();} /5_!Y >W  
catch(Exception e){e.printStackTrace ();} p_ QL{gn  
\^3\_T&6  
B;':Eaa@  
Utility.log(nFileLength); }45&s9m=  
([ xYOxcp5  
Qp${/  
return nFileLength; sEL[d2oO  
} 'on, YEp  
@&d/}Mx"t  
OY6l t.t  
//保存下载信息(文件指针位置) *Oo2rk nQ  
private void write_nPos() cX553&  
{ b07 MTDFH7  
try{ i3>7R'q>  
output = new DataOutputStream(new FileOutputStream(tmpFile)); qGgT<Rd~1  
output.writeInt(nStartPos.length); Zcv1%hI  
for(int i=0;i<nStartPos.length;i++) )fR'1_  
{ o% !a  
// output.writeLong(nPos); %Ow,.+m  
output.writeLong(fileSplitterFetch.nStartPos); 1NT@}j~/  
output.writeLong(fileSplitterFetch.nEndPos); x5 3 aGi|  
} <$HP"f+<S5  
output.close(); /'p(X~X:l  
} ?E2/ CM  
catch(IOException e){e.printStackTrace ();} '8wA+N6Zr7  
catch(Exception e){e.printStackTrace ();} #Gs] u  
} 5"6Y=AuQ6  
xq.,7#3  
l>S~)FNwXJ  
//读取保存的下载信息(文件指针位置) i%0Ml:Y  
private void read_nPos() y#^d8 }+  
{ kL,AY-Iu{@  
try{ X%S?o  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); pNI=HHx  
int nCount = input.readInt(); pVP CxP  
nStartPos = new long[nCount]; {cKKTDN  
nEndPos = new long[nCount]; N/mTG2'<  
for(int i=0;i<nStartPos.length;i++) C jsy1gA  
{ Fmk, "qs  
nStartPos = input.readLong(); hIC$4lR~  
nEndPos = input.readLong(); x2[A(O=  
} FU~ Ip  
input.close(); IiIF4 pQ,  
} ~(%nnG6x  
catch(IOException e){e.printStackTrace ();} aDTNr/I  
catch(Exception e){e.printStackTrace ();} 3xh~xE  
} {(A Ys*5  
'ac %]}`-  
M"#xjP.  
private void processErrorCode(int nErrorCode) 5R/!e`(m  
{ k 0z2)3L  
System.err.println("Error Code : " + nErrorCode); ">lu8F  
} ;2-,Xzz8  
'$PiyM|V  
Qhsh{muw(  
//停止文件下载 /A4zR  
public void siteStop() 4E}/{1  
{ tD.md _E  
bStop = true; |28z4.  
for(int i=0;i<nStartPos.length;i++)  =h\,-8  
fileSplitterFetch.splitterStop(); (5re'Pl  
&hEtVkK  
KE`}P<K&  
} ]4yWcnf  
} B{lBUv(B  
//负责部分文件的抓取 'q8T*|/  
**FileSplitterFetch.java uMtq4.  
*/ `[w:l[i  
package NetFox; A$Mmnu%  
{xp/1? Mo*  
vZmM=hW~  
import java.io.*; iZB?5|*  
import java.net.*; ogH{   
*f=H#  
1j "/}0fx  
public class FileSplitterFetch extends Thread { @S yGj#  
mTT1,|  
gh|TlvnA  
String sURL; //File URL 3G dWq*  
long nStartPos; //File Snippet Start Position WrQe'ny  
long nEndPos; //File Snippet End Position fa;\4#  
int nThreadID; //Thread's ID t{| KL<d]  
boolean bDownOver = false; //Downing is over (V)nHF*<>  
boolean bStop = false; //Stop identical [84ss;.$  
FileAccessI fileAccessI = null; //File Access interface MJd!J ]E6  
Q}2aBU.f  
J1T_wA_  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ,8nu%zcVn  
{ |?hNl2m  
this.sURL = sURL; F$7>q'#  
this.nStartPos = nStart; i<l_z&  
this.nEndPos = nEnd; K2<"O qp_W  
nThreadID = id; 7,ysixY  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ) RS*MEgA  
} Va"Q1 *"  
fgK1+sW  
Pk!RgoWF  
public void run() Tz[ck 'k  
{ [QEV6 S]  
while(nStartPos < nEndPos && !bStop) F~2bCy[Z  
{ ) gbns'Z<  
w5w,jD[  
_8Cw_  
try{ GuPxN}n 5  
URL url = new URL(sURL); t<wjS|4  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); (-viP  
httpConnection.setRequestProperty("User-Agent","NetFox"); X?&(i s  
String sProperty = "bytes="+nStartPos+"-"; U1}-]^\  
httpConnection.setRequestProperty("RANGE",sProperty); +Kw:z?  
Utility.log(sProperty); }lt5!u~}  
GKTt!MK  
N"1o> !  
InputStream input = httpConnection.getInputStream(); d(9ZopJrQ  
//logResponseHead(httpConnection); @&#k['c  
 L_3Ao'SA  
$L7Z_JD5  
byte[] b = new byte[1024]; YEH /22  
int nRead; p'{B|ujj6  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) oJb${k<3  
{ n@xC?D:t*  
nStartPos += fileAccessI.write(b,0,nRead); Oo^kV:.)  
//if(nThreadID == 1) jD1/`g%  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ;c p*]  
} ^3"~ T  
/k8Lu+OJ  
Wu3or"lcw*  
Utility.log("Thread " + nThreadID + " is over!"); g<pr(7jO  
bDownOver = true; $p:RnH\H1  
//nPos = fileAccessI.write (b,0,nRead); vy&'A$ H  
} X5@+M!`  
catch(Exception e){e.printStackTrace ();}  |Hx#Uk#  
} V>D8l @  
} 4eH:eCZze  
(7Su{tq  
P/i{_r  
//打印回应的头信息 hOZ:r =%  
public void logResponseHead(HttpURLConnection con) >-U'mkIH  
{ 3L}eF g,d  
for(int i=1;;i++) 'KvS I=$  
{  ac  
String header=con.getHeaderFieldKey(i); kNq>{dNRx  
if(header!=null) |H-%F?<{  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Qw>~] d,Z  
Utility.log(header+" : "+con.getHeaderField(header)); c12mT(+-  
else NxY B)`~  
break; >7g #e,d   
} 'Ur1I "  
} 6mp8v`b  
#+CH0Z  
sg YPR  
public void splitterStop() gOiZ8K!  
{ Uh[MB wK  
bStop = true; ` 1Ui  
} ;]v{3m  
|5il5UP  
7v'aw"~  
} J9aqmQj('  
U{1%ldOJ%  
xB5qX7*.  
/* p>#sR4d>  
**FileAccess.java Q1kZ+b&  
*//文件访问(定位,写) F8xz^UQO  
package NetFox; ^mH:8_=(.  
import java.io.*; To/6=$wto  
2 |`7_*\  
aSse' C<a  
public class FileAccessI implements Serializable{ 74_':,u;]~  
}%75 Wety  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 z)%Ke~)<\@  
RandomAccessFile oSavedFile; S\76`Ot  
long nPos; u~rPqBT{d3  
Q|KD$2rB  
c,>y1%V*S{  
public FileAccessI() throws IOException {L'uuG\9U  
{ 3~q#P   
this("",0); B*Z}=$1j  
} osM[Xv  
&=f] a  
,FIG5-e,}  
public FileAccessI(String sName,long nPos) throws IOException 'p_|Rw>  
{ af@R\"N9c  
oSavedFile = new RandomAccessFile(sName,"rw"); , wXixf2  
this.nPos = nPos; E!A+J63zsw  
oSavedFile.seek(nPos); B,V:Qs6"  
} pk8`suZ  
hZIbN9)8A  
L;\f^v(  
public synchronized int write(byte[] b,int nStart,int nLen) ]ZR}Pm/CA  
{ v[~~q  
int n = -1; U8S<wf&  
try{ t $m:  
oSavedFile.write(b,nStart,nLen); `}:pUf  
n = nLen;  "tT68  
} cqYMzS t  
catch(IOException e) P(o GNKAS  
{ 4V<.:.k  
e.printStackTrace (); 9y'To JZ6  
} _|r/* (hh  
Y sDai<  
%y)]Q|  
return n;  sWyx_  
} F4NM q&_  
'QSj-  
7Y?59 [  
} _U|rTil  
Ddh  
xLdkeuL[%  
/* %MCJ%Ph  
**SiteInfoBean.java &8;Fi2}(L  
*/ / z m+  
package NetFox; g-pEt#  
h e=A%s  
[jz@d\k$_  
public class SiteInfoBean { HQZJK82  
wZ5k|5KtW  
P^aNAa  
private String sSiteURL; //Site's URL j ];#=+  
private String sFilePath; //Saved File's Path EG8%X"p  
private String sFileName; //Saved File's Name ZU$QwI8  
private int nSplitter; //Count of Splited Downloading File ep6V2R  
18^K!:Of  
wG&Z7C b  
public SiteInfoBean() |w"G4J6ha  
{//nSplitter的缺省值为5 =}" P;4:  
//default value of nSplitter is 5 a8YFH$Xh  
this("","","",5); !a4`SjOgu  
} ')T*cLQ><  
]`q]\EH  
%!7A" >ai  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ^S`N\X  
{ mg< v9#  
sSiteURL= sURL; d};[^q6X  
sFilePath = sPath; ov5g`uud  
sFileName = sName; )gx*;z@  
this.nSplitter = nSpiltter; t*`G@Nj  
)EK\3q  
S c ijf 9  
} %CZGV7JdA  
IL,iu  
33ZHrZ  
public String getSSiteURL() Jt:)(&-t   
{ _VB;fH$  
return sSiteURL; 4j}.=u*X7  
} @X2zIFm  
?AVnv(_  
bN&DotG  
public void setSSiteURL(String value) :*vSC:q  
{ _}gfec4o  
sSiteURL = value; [x%8l,O #l  
} eNK6=D|  
y(*5qa<>  
{`Z= LLL  
public String getSFilePath() HqI[]T@  
{ `46|VQAx  
return sFilePath; S\ K[l/  
} z%]3`_I  
M96Nt&P`  
qYPgn _  
public void setSFilePath(String value) L'$({  
{ Zbr1e5?  
sFilePath = value; =Qn8Y`U  
} iOk`_LG#  
i!G<sfL  
hXD`OlX  
public String getSFileName() xouBBb=  
{ b)>l7nOc  
return sFileName; tR .>d  
} "u'dd3!  
-M+o;  
)+"(7U<  
public void setSFileName(String value) 1]W8A.ZS  
{ g2vt(Gf;  
sFileName = value; *l@T 9L[M'  
} @.=2*e.z|b  
VrKLEN\  
djn<Oc`  
public int getNSplitter() t Kjk<  
{ uG/b Cb+V  
return nSplitter; KkJE-k*D+w  
} ug/P>0  
Ko!a`I2M}  
]E*xn  
public void setNSplitter(int nCount) 6J965eM'[  
{ cef:>>6_  
nSplitter = nCount; <899r \  
} X;{U?`b-  
} ;T<'GP'/r  
mp0s>R  
SwO8d;e  
/* J=H8^4M  
**Utility.java ()fYhk|W  
*/  ?QcS$i  
package NetFox; IFXnGDG$  
'h> l_A  
>p3S,2SM  
public class Utility { pW&8 =Ew  
cr!sq.)s  
m;<5QK8f  
public Utility() ZV!*ZpTe~  
{ 9x14I2  
s{fL~}Yz  
ai)?RF  
} lC^?Jk[N  
`J}FSUn\  
//线程睡眠 ` kZ"5}li  
public static void sleep(int nSecond) d 8z9_C-  
{ L @8[.  
try{ c- [IgX e  
Thread.sleep(nSecond); UFE~6"t(  
} ?osYs<k \  
catch(Exception e) 'fIG$tr9X  
{ =/N0^  
e.printStackTrace (); ?o(Y\YJf  
} I -XkxDw  
} ,`(Qs7)Xx  
zENo2#{_N  
//日志 /j:-GJb*!u  
public static void log(String sMsg) ]r1Lr{7^S  
{ Y2>*' nU  
System.err.println(sMsg); k")3R}mX  
} )1&,khd/u  
SU4~x0  
z\<gm$1CB  
public static void log(int sMsg) $t>ow~Xi  
{ rzKn5Z  
System.err.println(sMsg); a@-!,Hi  
} e pAC%a  
} =l$qwcfbo  
lW@i,1  
zh4m`}p  
/* t<qXXQ&5  
**TestMethod.java CHM+@lD  
*/ iu'rc/=V  
package NetFox; 3]/Y= A  
`{\10j*B  
SA6.g2pFz  
public class TestMethod { j"<F?k@`Q  
[u8JqX  
V[">SiOg  
public TestMethod() LMYO>]dg  
{ ///xx/weblogic60b2_win.exe -GL-&^3IjH  
try{ f>+:UGmP  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); oz?6$oE(bt  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); M+\LH  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 5?MKx!%  
fileFetch.start(); !%YV0O0  
} S]DYEL$  
catch(Exception e){e.printStackTrace ();} "cX*GTNi8  
V, e  
5,?Au  
} j=w`%nh4"f  
qo0]7m7|  
QLyBP!X-  
public static void main(String[] args) PF-"^2&_  
{ 2ZFp(e^%  
new TestMethod(); Fy]j33E  
} +DP{_x)t  
} f<( ysl1[  
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