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http断点续传简单实现(java)

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/* tKLeq(  
**SiteFileFetch.java !> +Lre@  
*/ >yn]h4M  
package NetFox; mk!8>XvM  
import java.io.*; w42{)S"  
import java.net.*; SC4jKm2  
5WRqeSGh  
CALD7qMK  
public class SiteFileFetch extends Thread { 7_qsVhh]$E  
|ZifrkD=  
=1R 2`H\  
SiteInfoBean siteInfoBean = null; //文件信息Bean =LK`m NA  
long[] nStartPos; //开始位置 .B2e$`s$  
long[] nEndPos; //结束位置 M!!vr8}  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 !]A/ID0K  
long nFileLength; //文件长度 N5=}0s]e  
boolean bFirst = true; //是否第一次取文件 ^mFsrw  
boolean bStop = false; //停止标志 w_@{v wM$A  
File tmpFile; //文件下载的临时信息 qk3 ~]</  
DataOutputStream output; //输出到文件的输出流  ?f'`b<o  
Hmhsb2`\  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) Y:m8UnT  
public SiteFileFetch(SiteInfoBean bean) throws IOException Nb_Glf  
{ mr G?5.7W  
siteInfoBean = bean; w~crj$UM  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 8?kB+}@6X  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 1pDU}rPJ.  
if(tmpFile.exists ()) :R:@V#Y  
{ tK{#kApHGG  
bFirst = false; <zvtQ^{]  
read_nPos(); _4SZ9yu  
} # .(f7~  
else lV 4TFt ,  
{ 7SYe:^Dx  
nStartPos = new long[bean.getNSplitter()]; d#bg(y\G|  
nEndPos = new long[bean.getNSplitter()]; %P<fz1  
} h,BPf5\S  
$t"QLsk0  
+N+117m  
mr#.uhd.z  
} Fec4#}|  
Z> Rshtg  
<6+B;brh  
public void run() *9=}f;~  
{ CW8YNJ'  
//获得文件长度 AU%Yr 6  
//分割文件 p= x &X~  
//实例FileSplitterFetch !J<0.nO/:  
//启动FileSplitterFetch线程 4[;}/-  
//等待子线程返回 b 1Wz  
try{ [] "bn9 +  
if(bFirst) T8&sPt,f  
{ u R5h0Fi  
nFileLength = getFileSize(); `}sFT:1&  
if(nFileLength == -1) rZ-< Ryg  
{ 1)ij*L8k  
System.err.println("File Length is not known!"); tlvZy+Blv  
} G^K;+&T  
else if(nFileLength == -2) 4K`b?{){+a  
{ 3y2L! &'z  
System.err.println("File is not access!"); [`tNa Vg  
} CA&VnO{r  
else $/#[,1  
{ >>C S8  
for(int i=0;i<nStartPos.length;i++) zlQBBm;fE  
{ "o u{bKe  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); i-4L{T\K  
} y,n.(?!*  
for(int i=0;i<nEndPos.length-1;i++) xpuTh"ED  
{ eA?|X|  
nEndPos = nStartPos[i+1]; T7/DH  
} eA Fp<2g  
nEndPos[nEndPos.length-1] = nFileLength; x]%,?Vd?  
} Gkfzb>_V]  
} ~/aCzx~  
j)iUg03>/4  
\ /Q~C!  
//启动子线程 X#ha*u~U  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; *x p_#  
for(int i=0;i<nStartPos.length;i++) 0ZI}eZA j  
{ y>u |3:z  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 7!Im|7Ty  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ttlMZLX{TJ  
nStartPos,nEndPos,i); Y@MxKKuj  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); UM21Cfqex  
fileSplitterFetch.start(); kqo4 v;r  
} :2vuc!Pu  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), j8^ #698X  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); t*Z5{   
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", FBouXu#  
nEndPos = " + nFileLength); !lsa5w{  
// fileSplitterFetch[nPos.length-1].start(); |90/tNe  
}>621L3 -  
+N2ILE8[<  
//等待子线程结束 g@/}SJh/>  
//int count = 0; TEj"G7]1$A  
//是否结束while循环 -*T0Cl.  
boolean breakWhile = false; KZAF9   
PX/^*  
K~3Y8ca  
while(!bStop) p g_H'0R  
{ ^AOJ^@H^>  
write_nPos(); B^R44j]3"  
Utility.sleep(500); , v=pp;  
breakWhile = true; QpoC-4F  
x6Gl|e[jv  
Tl]yl$  
for(int i=0;i<nStartPos.length;i++) w6Mv%ZO_  
{ TMs Cl6dB  
if(!fileSplitterFetch.bDownOver) tBl (E  
{ ^x^(Rk}|  
breakWhile = false; l)jP!k   
break; f$dIPt(  
} #a tL2(wJ  
} )_o^d>$da  
if(breakWhile) 4N7|LxNNl_  
break; akCCpnX_d  
swJQwY   
 ]EQ*!  
//count++; o :4#Ak S  
//if(count>4) _E6N*ORV  
// siteStop(); zq?xY`E  
} 8$ X3J[_j  
10m|?  
2 1+[9  
System.err.println("文件下载结束!"); Q~' \oWz  
} 2!b##`UjA7  
catch(Exception e){e.printStackTrace ();} `Nz`5}8.?  
} .XkVdaX  
`P:[.hRu  
H<?s[MH[  
//获得文件长度 -2 8bJ,  
public long getFileSize() "d}ey=$h4  
{ Co=Bq{GY  
int nFileLength = -1; (#z6w#CU(  
try{ ^7;s4q  
URL url = new URL(siteInfoBean.getSSiteURL()); $2}%3{<j  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); EUV8H}d5  
httpConnection.setRequestProperty("User-Agent","NetFox"); &=:3/;c  
ZYt<O  
&Ll&A@yU  
int responseCode=httpConnection.getResponseCode(); G)Y,*.,  
if(responseCode>=400) uAoZ&8D6  
{ @^g~F&Ta  
processErrorCode(responseCode); HRu;*3+%>F  
return -2; //-2 represent access is error D$NpyF.87  
} X2:23j<  
WlGT&m&2  
d 792#Dc  
String sHeader; O;}K7rSc  
[U"/A1p  
JB.U&  
for(int i=1;;i++) uq54+zC  
{ ]0|A\bE\S  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 7~k=t!gTY  
//Utility.log(in.readLine()); t&EY$'c  
sHeader=httpConnection.getHeaderFieldKey(i); N qz6_!  
if(sHeader!=null) 0bIgOLP  
{ n:k4t  
if(sHeader.equals("Content-Length")) +#<Z/  
{ M1*bT@ 6  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); H?xY S| n  
break; QH,(iX6RY  
} o?a3hD  
} "QiLu=Rq  
else [9NrPm3d  
break; x#R6Ez7  
} ?0+g.,9  
} e :C4f  
catch(IOException e){e.printStackTrace ();} nf1 `)tXG  
catch(Exception e){e.printStackTrace ();} P$*Ngt  
\ a(ce?C  
B_b5&M@  
Utility.log(nFileLength); [8[<4~{  
Y#=MN~##t  
T5.^ w  
return nFileLength; >V]9<*c  
} ,j.bdlI#  
jcBZ#|B7;  
n5IQKYr g  
//保存下载信息(文件指针位置) V RD^>Gi  
private void write_nPos() MHye!T6fO\  
{ 2\gIjXX"  
try{ b >k2@  
output = new DataOutputStream(new FileOutputStream(tmpFile)); C4|OsC7J  
output.writeInt(nStartPos.length); {B6ywTK\ `  
for(int i=0;i<nStartPos.length;i++) ~(GN Y5  
{ $ b53~  
// output.writeLong(nPos); r`h".=oD  
output.writeLong(fileSplitterFetch.nStartPos); ~<s^HP2U{  
output.writeLong(fileSplitterFetch.nEndPos); urCTP.F  
} ~{vB2  
output.close(); kY{$[+-jR  
} LNHi }P~  
catch(IOException e){e.printStackTrace ();} { w sT  
catch(Exception e){e.printStackTrace ();} v'S5F@ln  
} BNI)y@E^X  
:g^ mg-8  
TOS'|xQ  
//读取保存的下载信息(文件指针位置) dh&> E  
private void read_nPos() [+ xsX*+  
{ HiH<'m"\.  
try{ PB8g4-?p6  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); )4c?BCgy  
int nCount = input.readInt(); R:R<Xt N`5  
nStartPos = new long[nCount]; CgYX^h?Y9  
nEndPos = new long[nCount]; WW &Wh<4  
for(int i=0;i<nStartPos.length;i++) lmD [Cn  
{ n 9`]}bnX  
nStartPos = input.readLong(); G43r85LO  
nEndPos = input.readLong(); {P_7AM  
} Fkq^2o ]  
input.close(); _nxH;Za  
} +{I" e,Nk  
catch(IOException e){e.printStackTrace ();} %%>nM'4<  
catch(Exception e){e.printStackTrace ();} $AE5n>ZD$  
} b(Tvc  
(j??  
M6Np!0G  
private void processErrorCode(int nErrorCode) e"NP]_vh,  
{ #Nco|v  
System.err.println("Error Code : " + nErrorCode); C"_ Roir?  
} h0g?=hJq  
/S1/ZI  
Qx8(w"k*  
//停止文件下载 CS(2bj^6 D  
public void siteStop() p:W]  
{ .jk A'i@  
bStop = true; ;+6><O!G  
for(int i=0;i<nStartPos.length;i++) &);P|v`8  
fileSplitterFetch.splitterStop(); kV4Oq.E  
3JBXGT0gJ  
5r~jo7  
} N~l*//Ep  
} P*~ vWYH9  
//负责部分文件的抓取 1;V_E2?V  
**FileSplitterFetch.java ~!8j,Bqs+z  
*/ ka8Y+Gs  
package NetFox; b.@4yW  
LyWY\K a  
[wnp]'+!  
import java.io.*; b:p0@|y  
import java.net.*; 0`-b57lF&  
DZnqCu"J  
%DXBl:!Y`  
public class FileSplitterFetch extends Thread { K%x]:|,>M  
g,]m8%GHE  
J@6j^U  
String sURL; //File URL -C3[:g  
long nStartPos; //File Snippet Start Position s*<T'0&w0S  
long nEndPos; //File Snippet End Position )`R}@(r.  
int nThreadID; //Thread's ID U&V u%+B  
boolean bDownOver = false; //Downing is over rVl 8?u y  
boolean bStop = false; //Stop identical fi%i 2Wy  
FileAccessI fileAccessI = null; //File Access interface (tg9"C  
; teM^zyI  
 -D'XxOI  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Bdb}4X rL  
{ JcmJq fR  
this.sURL = sURL; Dm5 Uy^F}  
this.nStartPos = nStart; wL="p) TO.  
this.nEndPos = nEnd; t&J A1|q  
nThreadID = id; seBmhe5qR  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 h@G~' \8t  
} LSJ.pBl\X  
tO:JB&vO2  
'xx M0Kn`  
public void run() 7H< IO`  
{ *URT-+'  
while(nStartPos < nEndPos && !bStop) tzIP4CR~F&  
{ "V 26\  
$6pLsX  
/]!2 k9u\  
try{ Bps%>P~.  
URL url = new URL(sURL); a{hc{  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); BO G.[?yx  
httpConnection.setRequestProperty("User-Agent","NetFox"); _avf%OS  
String sProperty = "bytes="+nStartPos+"-"; |. 0~'  
httpConnection.setRequestProperty("RANGE",sProperty); _O uNX.yrG  
Utility.log(sProperty); M.- {->  
~h;   
4dPTrBQ?  
InputStream input = httpConnection.getInputStream(); d9;&Y?fp  
//logResponseHead(httpConnection); &|#[.ti1  
B#jnM~fJz  
nv@z;#&  
byte[] b = new byte[1024]; |`#fX(=  
int nRead; E(|A"=\  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) # 5)/B  
{ v>B412l  
nStartPos += fileAccessI.write(b,0,nRead); __.MS6"N  
//if(nThreadID == 1) f?)7MR=  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); <;PKec  
} J*$%d1  
/[FDiJH2  
Zdqm|_R[  
Utility.log("Thread " + nThreadID + " is over!"); |;wc8;  
bDownOver = true; gI;"PkN  
//nPos = fileAccessI.write (b,0,nRead); `7: uc@  
} eQu(3sYb  
catch(Exception e){e.printStackTrace ();} j0; ~2W#G*  
} :1j8!R5  
} Si?s69  
-GPJ,S V>  
CMW4Zqau*  
//打印回应的头信息 P7XZ|Td4*  
public void logResponseHead(HttpURLConnection con) v4"Ukv  
{ EXr2d"  
for(int i=1;;i++) Nb&j?./  
{ 3U{ mC}F  
String header=con.getHeaderFieldKey(i); [-_{3qq<e  
if(header!=null) |di(hY|  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); $5JeN{B  
Utility.log(header+" : "+con.getHeaderField(header)); ]wU/yc)e  
else O?Bf (y  
break; fOHbgnL>  
} x'x5tg  
} 2MRd  
JVX)>2&$  
<.n,:ir  
public void splitterStop() Gc`PO  
{ c#{lXS^  
bStop = true; j*?8w(!  
} /f1]U LmC:  
\(i'iC  
{S{%KkAV  
} 72OqXa*  
A[+)PkR  
0>BxS9?w  
/* ay7\Ae]  
**FileAccess.java ;^xM" {G8  
*//文件访问(定位,写) u>fMO9X} 2  
package NetFox; 6U*CR=4  
import java.io.*; bQautRW  
MRt"#CO  
W:RjWn@<  
public class FileAccessI implements Serializable{ )hrsA&1w  
D;0>-  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 rH`\UZ{cc  
RandomAccessFile oSavedFile; i|1*bZ6'  
long nPos; }( F:U#  
toPbFU'  
}9"'' Z  
public FileAccessI() throws IOException u @Ze@N%  
{ w UxFE=ia  
this("",0); e&z@yy$  
} )\Q(=:  
xA Ez1  
ck{S  
public FileAccessI(String sName,long nPos) throws IOException ,<%uG6/",g  
{ xkDK5&V  
oSavedFile = new RandomAccessFile(sName,"rw"); "KP]3EyPc  
this.nPos = nPos; 6NX#=A  
oSavedFile.seek(nPos); F9o7=5WAb  
} \lQ3j8 U  
-fPiHKJ  
_l7_!Il_  
public synchronized int write(byte[] b,int nStart,int nLen) O"'xAPQW  
{ } e$  
int n = -1; ,N(Yjq"R  
try{ P'qBqx[  
oSavedFile.write(b,nStart,nLen); jvB[bS`<H  
n = nLen; V gMgeja  
} YYn8!FIe  
catch(IOException e) BF W b0;+  
{ yIKpyyC9H  
e.printStackTrace (); _!o8s%9be  
} $!*>5".A  
/3aW 0/^o  
o9e8Oj&  
return n; T9V=#+8#"  
} Bn]=T  
E_=F' sP?  
jXeE]A"  
} T>asH  
.1[.f}g$J  
CImp,k0  
/* G"?7 Z&+  
**SiteInfoBean.java Xeq9Vs zg  
*/ <Ja&z M  
package NetFox; F NPu  
SQ,-45@W  
wL8j i>"  
public class SiteInfoBean { X\Bl? F   
\B4H0f  
aPelt`  
private String sSiteURL; //Site's URL gw"cXny  
private String sFilePath; //Saved File's Path Cy?]o?_?  
private String sFileName; //Saved File's Name 1]:,Xa+|S  
private int nSplitter; //Count of Splited Downloading File {KHI(*r;  
M3-lL;!n  
,A{Bx`o?  
public SiteInfoBean() DKt98;  
{//nSplitter的缺省值为5 C<J*C0vQO  
//default value of nSplitter is 5 8S#$'2sT  
this("","","",5); X "7CN Td  
} B`-uZ9k   
k3$'K}=d  
VF2,(f-*  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) qIuo8o}  
{ .5Y{Yme  
sSiteURL= sURL; U6/7EOW,  
sFilePath = sPath; W$`v^1M2o  
sFileName = sName; ( 3B1X  
this.nSplitter = nSpiltter; o)5zvnu7  
J-<P~9m~I  
vE )N6Ss  
} gg#9I(pX  
hhPQ.{]>  
g*b`o87PI  
public String getSSiteURL() c)#7T<>*'  
{ R7Qj<,  
return sSiteURL; ywp_,j9F  
} aaU4Jl?L  
PFp!T [)  
01@ WU1IN  
public void setSSiteURL(String value) "^z%|uXkf  
{ [l^XqD D4  
sSiteURL = value; ,mm97I  
} 'df@4}9  
'|]}f}Go  
Mk#r_:[BS  
public String getSFilePath() tkV[^OeU>  
{ a&G{3#l  
return sFilePath; aiX&`   
} c<_1o!68  
Jy:*GW6  
nq?+b >//  
public void setSFilePath(String value) ;cf$u}+  
{ -I{op wd  
sFilePath = value; /ZiMD;4@y  
} B)7:*Kj  
di_UJ~  
1 0zM8<bl  
public String getSFileName() $DH/  
{ TkTGYh  
return sFileName; KLM6#6`  
} ;sA 5&a>!  
mH;t)dT  
8-+# !]  
public void setSFileName(String value) by9UwM=gp  
{ 0>j0L8#^p  
sFileName = value; ds(X[7XGW  
} / P@P1l|I  
Uot(3p!S6  
\68bXY.  
public int getNSplitter() _lI(!tj(  
{ 8Q/cJ+&  
return nSplitter; Tg O]q4  
} H8"RdKwg?  
g&/lyQ+G  
"n3n-Y#'  
public void setNSplitter(int nCount) RQ|K?^k v  
{ Vfd_nD^8oZ  
nSplitter = nCount; ISZEP8w  
} ^Vth;!o  
} t@lTA>;U@  
" AvEo  
i8Be%y%y  
/* A* qR<cp[  
**Utility.java `vt+VUNf  
*/ YH^U "\}i  
package NetFox; (~\HizSl  
fATnza  
y46sL~HRv  
public class Utility { U{EcV%C2  
Dp*:oMATx0  
uUaDesz~=  
public Utility() ?a+J4Zr3  
{ D {E,XOi  
tWZ8(E$  
CiU^U|~'L  
} Q.4+"JoG  
}}Q h_(  
//线程睡眠 _JpTHpqu  
public static void sleep(int nSecond)  w D  
{  [Ketg  
try{ C.=%8|Zy  
Thread.sleep(nSecond); F$v^S+Ch  
} cPL6(&7  
catch(Exception e) l}S96B  
{ sFk{Tv@Yz  
e.printStackTrace (); 'u PI~l`g  
} JvT#Fxjk  
} 4nd)*0{ f  
Ktuv a3=>N  
//日志 Xhyc2DKa_  
public static void log(String sMsg) %MtaWZ  
{ (Gzq 1+B  
System.err.println(sMsg); :gkn`z  
} *Q -uE  
'&AeOn  
>r:z`^p  
public static void log(int sMsg) 4[r:DM|8  
{ bA"*^"^  
System.err.println(sMsg); 7'.6/U  
} #)DDQ?D  
} A9HgABhax  
(ia+N/$u  
?6[u\V  
/* e oFM  
**TestMethod.java 7m(9|Y:Q.  
*/ l>Zp#+I-  
package NetFox; @MH/e fW.  
Hg]iZ,8?  
(=53WbOh/t  
public class TestMethod { ~:="o/wo  
L@ N\8mf  
&C/,~pJ1S  
public TestMethod() QUdF`_U7  
{ ///xx/weblogic60b2_win.exe DQ6pe)E|  
try{ AdF[>Wv  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); I} ]s(  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); oM}P Wf-  
SiteFileFetch fileFetch = new SiteFileFetch(bean); / vzwokH  
fileFetch.start(); rYyEs I#qo  
} g3w-Le&T  
catch(Exception e){e.printStackTrace ();} s\ ]Rgi>w  
_l]rt  
W<H^V"^  
} ra\2BS)X  
1z8AK"8  
0j-;4>p  
public static void main(String[] args) mhnK{M @56  
{ ;Uj=rS`Q  
new TestMethod(); KMkX0+Ao  
} {uO2m*JrI  
} %lK]m`(  
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