http断点续传简单实现（java)

/* Tf0#+6 1>  
**SiteFileFetch.java jY?%LY@5I  
*/ *smo{!0Gg  
package NetFox; `aI%laj&M  
import java.io.*;  b'Uaj`Sn  
import java.net.*; :!A@B.E  
z(%Zji@!N  
W4YC5ZH{l  
public class SiteFileFetch extends Thread { 4*dT|NU  
"1#,d#Q$  
1%=,J'AH  
SiteInfoBean siteInfoBean = null; //文件信息Bean -0\$JAyrx  
long[] nStartPos; //开始位置 7I.[1V`  
long[] nEndPos; //结束位置 yWK[@;S]%  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 IaF79}^  
long nFileLength; //文件长度 oD}I{&=wa  
boolean bFirst = true; //是否第一次取文件 L|H{;r'  
boolean bStop = false; //停止标志 P2Eyqd8  
File tmpFile; //文件下载的临时信息 k<f*ns  
DataOutputStream output; //输出到文件的输出流 i/Hi  
(^Ln|3iz  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） !{3pp  
public SiteFileFetch(SiteInfoBean bean) throws IOException qzyQ2a_p  
{ $i`YtV  
siteInfoBean = bean; kdo)y(fn@  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); FVpe*]  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); QDDSJ>l5_T  
if(tmpFile.exists ()) kB:R-St  
{ @)0gXg  
bFirst = false; IWQ8e$N  
read_nPos(); `150$*K&B  
} }ps6}_FE  
else D6m>>&E['  
{ r:o!w7C:a  
nStartPos = new long[bean.getNSplitter()]; \4&g5vE  
nEndPos = new long[bean.getNSplitter()]; 6RtpB\hq  
} '\;tmD"N5#  
:dj@i6  
1h"B-x  
d8K^`k+x  
}  )Ob{]  
l%:_#1?isf  
l{3utQH-=z  
public void run() /za,&7sf  
{ ]Lh\[@#1f  
//获得文件长度 4q~E\l|.5  
//分割文件 &Y&zUfA  
//实例FileSplitterFetch r9U1O@c  
//启动FileSplitterFetch线程 c
*W$wr  
//等待子线程返回 5u8Sxfm",  
try{ YJ0[BcZ  
if(bFirst) [+1 i$d  
{ 2,fB$5+  
nFileLength = getFileSize(); R3<+z  
if(nFileLength == -1) $200?[  
{ qnlj~]NV  
System.err.println("File Length is not known!"); npF[J x[  
} n-Xj>  
else if(nFileLength == -2) =sm(
Z;"  
{ YUH/t
l  
System.err.println("File is not access!"); M1i|qjb:l  
} _`(g?  
else {xr
]xcM'b  
{ ^Ve^}|qPc  
for(int i=0;i<nStartPos.length;i++) ~Mx fud  
{ (AS%P?  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 8?$2;uGL  
} v3NaX.  
for(int i=0;i<nEndPos.length-1;i++) /IC'R"V a  
{ Zry>s0  
nEndPos = nStartPos[i+1]; 7MfT~v  
} Y `{U45  
nEndPos[nEndPos.length-1] = nFileLength; q}!4b'z^  
} c'6H@m#=  
} x<l1s  
}B5I#Af7  
PX'LN  
//启动子线程 2Ar<(v$  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; zaZnL7ZJX  
for(int i=0;i<nStartPos.length;i++) RD4)NN6y5}  
{ 40<&0nn  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), u%pief  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 8%4`Yj=  
nStartPos,nEndPos,i); EI;\of2,  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %L/=heBBd  
fileSplitterFetch.start(); (pmo[2kg  
} q2Kn3{  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), EDo (  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); |h7v}Y  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ",
H07j&  
nEndPos = " + nFileLength); W)#`4a^xj7  
// fileSplitterFetch[nPos.length-1].start(); 5c"kLq
6r  
?Z=v&d[o)  
VC.?]'OqD  
//等待子线程结束 VPHCPGrk  
//int count = 0; -:,h8JyMP  
//是否结束while循环 r>Ln*R,9D  
boolean breakWhile = false; 8syo_sC |  
@K9T )p]  
+@Y[i."^J  
while(!bStop) +6=!ve}  
{ {OOt+U!  
write_nPos(); =(
ZGaZ}  
Utility.sleep(500); 4(R2V]  
breakWhile = true; fo.m&mKgo  
_a&|,ajy>  
.H"hRYPC?  
for(int i=0;i<nStartPos.length;i++)
FMVmH!E  
{ oo!g?X[[  
if(!fileSplitterFetch.bDownOver) qo@dFKy  
{ asg>TOW  
breakWhile = false; o >Lk`\  
break; Pio^5jhB6  
} z+*Z<c5d  
} #*!$!c{  
if(breakWhile) OLrD4 e  
break; 9zJ`;1  
R%%`wmG)"  
h uJqqC  
//count++; CC\z_C*P-p  
//if(count>4) K\b O[J  
// siteStop(); q8Dwu3D  
} i7rq;t<  
qx)k1QY  
GcnY=%L?  
System.err.println("文件下载结束！"); RY{tX`  
} g1~I*!p  
catch(Exception e){e.printStackTrace ();} x/=j$oA  
} j;)6uia*A  
uNbA>*c4M  
/<0D E22  
//获得文件长度 rHlF& ET  
public long getFileSize()  IMza 2  
{ GcR`{ 3hO  
int nFileLength = -1; {0 ~0  
try{ c*dw
w  
URL url = new URL(siteInfoBean.getSSiteURL()); lQBM0|n  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Gq*)]X{Ua  
httpConnection.setRequestProperty("User-Agent","NetFox"); j;)g+9`  
R(sM(x5a`  
PoJ$%_a}  
int responseCode=httpConnection.getResponseCode(); $hSZ@w|IF  
if(responseCode>=400) :2E1aVo4b  
{ j&A3s{S4A  
processErrorCode(responseCode); (GG"'bYk  
return -2; //-2 represent access is error 2~V Im#  
} >x4[7YAU{  
d8HB2c5y0i  
n5.>;N.*  
String sHeader; PQ}%}S7:  
Jj:6 c  
|8 bO5l:  
for(int i=1;;i++) {ah=i8$  
{ 9Yyg}l:  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); H
c]1mM  
//Utility.log(in.readLine()); [+g@@\X4  
sHeader=httpConnection.getHeaderFieldKey(i); wkD:i2E7  
if(sHeader!=null) (0W}e(D8  
{ Eap/7U1Q  
if(sHeader.equals("Content-Length")) y.p6%E_`  
{ Da[C'm=  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); N@6OQ:,[F  
break; Z=@)  
} Jwd&[ O  
} d&uTiH?0  
else toqzS!&.v  
break; .dT;T%3fO  
} OZD!#YI  
} R9h>I3F=c  
catch(IOException e){e.printStackTrace ();} p{q!jm~Nq  
catch(Exception e){e.printStackTrace ();} 4q13xX  
c1kxKxE  
W@,p9=425  
Utility.log(nFileLength); 
KC:4  
Reu{   
*Ca)RgM  
return nFileLength; 9
K':Fn2,  
} lt6
;*z[  
j yRSEk$  
=nx:GT3&[  
//保存下载信息（文件指针位置） H'{?aaK|t  
private void write_nPos() [!@oRK
=~  
{ `QdQ?9x{F  
try{ *xg`Kwl5Kl  
output = new DataOutputStream(new FileOutputStream(tmpFile)); +RV-VrV  
output.writeInt(nStartPos.length); S tnv>  
for(int i=0;i<nStartPos.length;i++) :KSor}t  
{ JhCkkw  
// output.writeLong(nPos); N4mJU'_{  
output.writeLong(fileSplitterFetch.nStartPos); +xf
W`[.{  
output.writeLong(fileSplitterFetch.nEndPos); +'/}[1q1/T  
} (\t_Hs::a  
output.close(); ZuvPDW%  
} EB5_;  
catch(IOException e){e.printStackTrace ();} Hpi%9SAM  
catch(Exception e){e.printStackTrace ();} `n`"g<K)Q  
} eQFb$C]R}y  
7TkxvSL X  
^mueFw}\  
//读取保存的下载信息（文件指针位置） ;Q=GJ5`B  
private void read_nPos() PKR $I  
{ }l(m5  
try{ $i:||L^8p  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); u'i%~(:$\)  
int nCount = input.readInt(); ;,=h59`  
nStartPos = new long[nCount]; F|?'9s*;6G  
nEndPos = new long[nCount]; :e]9T3Q  
for(int i=0;i<nStartPos.length;i++) j;20JA/b  
{ "6N~2q,SW  
nStartPos = input.readLong(); ,.jHV  
nEndPos = input.readLong(); s`=/fvf.  
} ~r^5-\[hZ  
input.close(); MJ*]fC3/  
} hiRR+`L%  
catch(IOException e){e.printStackTrace ();} cZr G:\A  
catch(Exception e){e.printStackTrace ();} hyb +#R  
} Q"|kW[Sg  
("E!Jyc!  
%gu$_S  
private void processErrorCode(int nErrorCode) )p<fL  
{ P$18Xno{  
System.err.println("Error Code : " + nErrorCode); 3`k[!!   
}
?,:#8.9  
NdsX*o@a  
?orhJS  
//停止文件下载 vZE|Z[M+<  
public void siteStop() 9G#8%[W  
{ |vfujzRZ  
bStop = true; +z|UpI  
for(int i=0;i<nStartPos.length;i++) ~
J1;tZS  
fileSplitterFetch.splitterStop(); r|^lt7\  
N(:nF5>_  
4e@&QOo`Cu  
} /e|[SITe  
} 8Y\OCwO  
//负责部分文件的抓取 Er"R;l]xJ  
**FileSplitterFetch.java LgP>u?]n  
*/ %e Sm&`  
package NetFox; y98JiNq  
\ I^nx+l  
W""*hJ  
import java.io.*; 9K;k%  
import java.net.*; 4r1<,{gCS  
*O+R|Cdp/  
>; &s['H  
public class FileSplitterFetch extends Thread { goDV2alC^  
"[*S?QO(L  
jj!N39f   
String sURL; //File URL }UKgF.  
long nStartPos; //File Snippet Start Position WVS$O99Y  
long nEndPos; //File Snippet End Position \[hn]@@  
int nThreadID; //Thread's ID 9DOkQnnc  
boolean bDownOver = false; //Downing is over [J)/Et  
boolean bStop = false; //Stop identical 7`IUM
Yl#~  
FileAccessI fileAccessI = null; //File Access interface "H>r-cyh  
jq57C}X}2  
q Vm"f,ruo  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 4D^ M<Xn  
{ =
`qRu  
this.sURL = sURL; x0\e<x9s  
this.nStartPos = nStart; -uA3Y  
this.nEndPos = nEnd; Z}8k[*.  
nThreadID = id; 48tcgFg[  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 M*5,O
 
} ]<27Sw&yaG  
17>5#JLP  
|}K  
public void run() E?Zb~xk  
{ I %|@3=Yc  
while(nStartPos < nEndPos && !bStop) %cH8
;5U40  
{ |XKOXa3.  
^IX%dzM  
_1>SG2h{fV  
try{ `d7gm;ykp  
URL url = new URL(sURL); @B,j;2eb  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); o'C~~Vg).  
httpConnection.setRequestProperty("User-Agent","NetFox"); .E+OmJwD  
String sProperty = "bytes="+nStartPos+"-"; "jL1.9%"  
httpConnection.setRequestProperty("RANGE",sProperty); u64@"P  
Utility.log(sProperty); #^|| ]g/N  
|',M_ e]  
z,pNb%*O  
InputStream input = httpConnection.getInputStream(); -#LjI.  
//logResponseHead(httpConnection); X=v~^8M7%  
5>k>L*5J  
wgY6D!Y   
byte[] b = new byte[1024]; }m6f^fs}  
int nRead; ?gLR<d_  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) [IiwNqZ[~  
{ In f9wq\  
nStartPos += fileAccessI.write(b,0,nRead); 9s!
2 wwh  
//if(nThreadID == 1) oW0gU?Rr)u  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); vO\:vp4fH  
} t]s94 R q  
~?#~Ar  
8r,9OM  
Utility.log("Thread " + nThreadID + " is over!"); }>2t&+v+  
bDownOver = true; gaQ[3g  
//nPos = fileAccessI.write (b,0,nRead); NW z9C=y  
} N0+hejz  
catch(Exception e){e.printStackTrace ();} b-PSm=`  
} B@-|b  
} hZcmP"wgC1  
k+FMZ,D|  
Le*`r2  
//打印回应的头信息 0|g[o:;fl_  
public void logResponseHead(HttpURLConnection con) NX?}{'f  
{ 5XDgs|8  
for(int i=1;;i++)
?TDvCL  
{ ?RHn @$g8M  
String header=con.getHeaderFieldKey(i); n_v02vFAHT  
if(header!=null) C(G(^_6  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 6N"m?g*Z d  
Utility.log(header+" : "+con.getHeaderField(header)); rwy+~  
else rfYP*QQY  
break; /vHYMS  
} d$pYo)8o({  
} dUIqDl  
8qn 9|  
OY:u',T  
public void splitterStop() >-b&v$  
{ 4S tjj!ew  
bStop = true; 0; 7#ji  
} `|nH1sHFq  
`19qq]  
U_]=E<el  
} B`i$Wt<7  
j_p
`Ng  
z) :ka"e  
/* 69>/@<   
**FileAccess.java ymYBm:"  
*//文件访问(定位，写) :$Q`>k7A  
package NetFox; 1Pm4.C)  
import java.io.*; 0Z"s_r}h  
jgG$'|s}  
E>E*ZZuhj  
public class FileAccessI implements Serializable{ P$
g^vS+  
qe<Hfp/p  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 XIKvH-0&  
RandomAccessFile oSavedFile; LT/mb2  
long nPos; S#tY@h@XV  
6ZcXS  
oe9lF*$/  
public FileAccessI() throws IOException &:<, c12  
{ fN@{y+6  
this("",0); pe.Ml7o"  
} u"`*DFjo*  
*7ZtNo[+  
=_l)gx+Y+y  
public FileAccessI(String sName,long nPos) throws IOException ++b$E&lYU  
{ |#k@U6`SG  
oSavedFile = new RandomAccessFile(sName,"rw"); }AlYNEY  
this.nPos = nPos; onwjn+"&  
oSavedFile.seek(nPos); l
-<`m#/v  
} Sm)u9  
V7EQ4Om:It  
TN\|fzj  
public synchronized int write(byte[] b,int nStart,int nLen) R:M,tL-l  
{ V,Q4n%h1.  
int n = -1; nBkh:5E5%  
try{ O#)jr-vXdV  
oSavedFile.write(b,nStart,nLen); 49AW6H.JT  
n = nLen; ^XG*z?Tt  
} `<U5z$^QTw  
catch(IOException e) ?F_)-  
{ 1yMr~Fo  
e.printStackTrace (); 7
VAJJv3  
} b5<okICD  
22&;jpL'?  
lj4o#^lC  
return n; .1#kDM  
} iG#}`  
kJT+  
i7w(S3a  
} H}/05e  
B2Z_]q$n*  
rOcg+5  
/* Y]Vq\]m\  
**SiteInfoBean.java BRzfic:e  
*/ 0J9D"3T)  
package NetFox; "j^MB)YD  
]A^4}CK^<  
"
hQgLG  
public class SiteInfoBean { #$E)b:xj  
jo9gCP.  
lyv4fP  
private String sSiteURL; //Site's URL >P=Q #;v  
private String sFilePath; //Saved File's Path rzUlO5?R=  
private String sFileName; //Saved File's Name aJzLrX  
private int nSplitter; //Count of Splited Downloading File cE\>f8 I  
!Ms[eB  
yCP4r6X0  
public SiteInfoBean() /TV=$gB`  
{//nSplitter的缺省值为5 Dvc&RG  
//default value of nSplitter is 5 e2cP *J  
this("","","",5); 6;iJ*2f5V  
} `XKVr  
l1'6cLT`  
3I $>uR  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 9t$]X>}  
{ %%JMb=!%2  
sSiteURL= sURL; R
#W&ery  
sFilePath = sPath; ~b)74M/  
sFileName = sName; Zsx3/}  
this.nSplitter = nSpiltter; $n!K6fkX%  
=a}b+(R  
"N5!mpD"  
} mbxbEqz  
}D;WN
@],  
(V?:]  
public String getSSiteURL() _zMgoc7  
{ =Vw 5q},3  
return sSiteURL; 69G`2_eKCp  
} Ba'LRz  
Bd~1P
/  
T.mmmT  
public void setSSiteURL(String value) -7{$Vj  
{ UbamB+QT  
sSiteURL = value; u0Nm.--;_3  
} Wl-<HR!n  
!
EIjN  
eOI (6U!  
public String getSFilePath() i'#Gy,R  
{ 4 %W:  
return sFilePath; )]htm&q5  
} j)C:$  
ye}p~&  
_O"mfXl6  
public void setSFilePath(String value) ep/Y^&$M  
{ 5jxQW ;  
sFilePath = value; 04U")-\O  
} N<(.%<!  
tjT>VwqH  
[U/(<?F{(  
public String getSFileName()  ._O  
{ ACq7dLys,B  
return sFileName; p< "3&HA  
} eKvV*[Na  
cLVeT  
tptN6Isuh  
public void setSFileName(String value) OTDg5:>  
{ H1n1-!%d  
sFileName = value; NMOut@  
} QPtGdd  
}g7]?Ee  
n\z,/'d"  
public int getNSplitter() Z|"p*5O,  
{ !> }.~[M  
return nSplitter; ,#?uJTLH  
} T"7~AbgNU  
$
(e#aHB  
&0zT I?c  
public void setNSplitter(int nCount) mZz=
"ZLa:  
{ 4(Iplo*Ys@  
nSplitter = nCount; G uQ=gN  
} UFAL1c<V  
} Xce0~\_A  
>K9#3 4hP  
mE%$HZ}  
/* _j?e~w&0b  
**Utility.java _WXtB#  
*/ l>*"mh  
package NetFox; y\
dEk:\)  
%\|'%/"`2(  
@c9^q>Uv  
public class Utility {
R218(8S  
B/~%h|
 
&`0/CV  
public Utility() \.YS%"Vz  
{ )WT>@  
%1}K""/  
D(-yjY8aG  
} w}Uhd,  
o*U]v   
//线程睡眠 s*U1  
public static void sleep(int nSecond) $un?0S  
{ `Qr%+OD  
try{ 9$`lIy@B  
Thread.sleep(nSecond); AL#4_]m'  
} bwiPS1+);  
catch(Exception e) l2N]a9bq@  
{ iY"l
}.7)  
e.printStackTrace (); \%^%wXfp  
} ]BR,M4   
} `;%]'F0`  
sVG(N.y  
//日志 ?T+q/lt4  
public static void log(String sMsg) Za
NQpH.  
{ U- )i+}Ng  
System.err.println(sMsg); J{^RkGF  
} E4m`  
,|&9M^  
A\8}|r(>9E  
public static void log(int sMsg) K2%w0ohC  
{ ,^#yo6-  
System.err.println(sMsg); KM^ufF2[  
} y~()|L[  
} ")=X4]D  
P#=`2a#G  
8 r_>t2$  
/* Aq
3}Ng
 
**TestMethod.java 5^^XQ?"  
*/ 8\:NMP8W\  
package NetFox; Kq i4hK  
AU2i%Q!  
kbM3  
public class TestMethod { 5mb]Q)f9-  
EkziAON  
yj^+G  
public TestMethod() $56,$K`H  
{ ///xx/weblogic60b2_win.exe xyI}y(CN1  
try{ /7gOSwY  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); q$=#A7H>3)  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); (<^yqH?  
SiteFileFetch fileFetch = new SiteFileFetch(bean); w*R$o
 
fileFetch.start(); )"pF R4  
} F_CYYGZ  
catch(Exception e){e.printStackTrace ();} 72'5%*1  
pR~U`r5z  
8<Hf"M  
} 5LOo8xN  
,cNLkoN  
eUg~)m5G  
public static void main(String[] args) e=.]F*:J  
{ ght$9>'n  
new TestMethod(); T?X_c"{8M  
} R=jI?p  
} x&0vKo;  
点击下载更多相关资料