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http断点续传简单实现(java)

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/* !\q'{x5C  
**SiteFileFetch.java v0%FG9Gk  
*/ 08nA}+k  
package NetFox; b .xG'  
import java.io.*; //^{u[lr  
import java.net.*; /J&_ZDNV~  
LT/ *y=  
2:6lr4{uY  
public class SiteFileFetch extends Thread { I"WmDC`1  
kM(,8j  
qK&h$;~*y  
SiteInfoBean siteInfoBean = null; //文件信息Bean ^O3p:X4u  
long[] nStartPos; //开始位置 |b|bL 7nx  
long[] nEndPos; //结束位置 U+@rLQ.-  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ?a~#`<  
long nFileLength; //文件长度 -L2% ,.E>4  
boolean bFirst = true; //是否第一次取文件 -qB{TA-.\  
boolean bStop = false; //停止标志 4'L.I%#tZ  
File tmpFile; //文件下载的临时信息 z s[zB#  
DataOutputStream output; //输出到文件的输出流 stOD5yi  
@P<Mc )o^  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) ODPWFdRar  
public SiteFileFetch(SiteInfoBean bean) throws IOException AH# Dk5#G  
{ (w/lZt  
siteInfoBean = bean; dca?(B!'6  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); y~rtYI  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ^:o^g'Yab  
if(tmpFile.exists ()) -q DL':  
{ ZJ |&t  
bFirst = false; Fr,b5 M<L7  
read_nPos(); oBWa\N  
} C.hRL4+;Zm  
else ajD/)9S  
{ !l1jQq_mK  
nStartPos = new long[bean.getNSplitter()]; }9Awv#+  
nEndPos = new long[bean.getNSplitter()]; j$khGR!  
} 6b h.5|  
e|.a%,Dcy  
 *l-F  
l gTw>r   
} n`|CD Kb  
?4lEHef  
bU_P@GKB  
public void run() S| l%JM^  
{ x7c#kU2A&Z  
//获得文件长度 #h2 qrX&+  
//分割文件 Ny 7vId  
//实例FileSplitterFetch ^xF-IA#ZeB  
//启动FileSplitterFetch线程 *Q,9 [k  
//等待子线程返回 lC=T{rR  
try{ 8"J6(KS  
if(bFirst) 1tFx Z#(G  
{ u!I=|1s  
nFileLength = getFileSize(); 6Vy4]jdT5  
if(nFileLength == -1) wZ~eE'zx+  
{ nbSu|sX~r5  
System.err.println("File Length is not known!"); `5t CmU  
} 3aEO9v,n  
else if(nFileLength == -2) !FbW3p f  
{ lA ZBlO  
System.err.println("File is not access!"); Zs}EGC~&  
} -o`|A767  
else d{RMX<;G  
{ 1IZTo!xi  
for(int i=0;i<nStartPos.length;i++) 4Pr@<S"U  
{ -y)g}D%  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); OG2&=~hOz-  
} wXUgxa  
for(int i=0;i<nEndPos.length-1;i++) F!ra$5u  
{ @i@f@.t  
nEndPos = nStartPos[i+1]; 87:V-*8  
} 3>buZ6vh  
nEndPos[nEndPos.length-1] = nFileLength; Ct9*T`Gl  
} j79$/ Ol  
} C: a</Sl  
t3;QF  
Hp-vBoEk  
//启动子线程 ' 8UhYwyr  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; to;cF6X  
for(int i=0;i<nStartPos.length;i++) $3{I'r]  
{ ,IQ%7*f;O_  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), txe mu *  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), %51HJB}C]  
nStartPos,nEndPos,i); AR5)Uw s  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); <~35tOpv  
fileSplitterFetch.start(); )r:gDd#/X  
} ?F@X>zR2  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), OT}^dPQe  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); +&8'@v$  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 1Et{lrgh f  
nEndPos = " + nFileLength); MF.$E?_R  
// fileSplitterFetch[nPos.length-1].start(); \$D41_Wt|  
;F\sMf{  
>&uR=Yd  
//等待子线程结束 yI_MY L[  
//int count = 0; XQ$9E?|=  
//是否结束while循环 <5sP%Fs)  
boolean breakWhile = false; _ }:#T8h  
e^Glgaf  
-Oc  
while(!bStop) NUGiDJ+[  
{ &3bhK5P  
write_nPos(); _&/2-3]\B  
Utility.sleep(500); 6eAJ >9@x  
breakWhile = true; #=aTSw X  
@!2vS@f  
!yf7y/qY  
for(int i=0;i<nStartPos.length;i++) ]ag^~8bG @  
{ Z^ }4bR]  
if(!fileSplitterFetch.bDownOver) QF9$SCmv  
{ (j884bu  
breakWhile = false; Qe1WT T]:I  
break; PW GN UNc  
}  '' Pfs<!  
} ?/^x)Nm  
if(breakWhile) !vH={40]  
break; ;@G5s+<l  
&Vmx<w  
=U+_;;F=  
//count++; k2ZMDU  
//if(count>4) { ^ @c96&  
// siteStop(); ^F`\B'8MF  
} O (YvE  
s!\G i5b  
R)BH:wg"  
System.err.println("文件下载结束!"); -{s9PZ3~_  
} cK~VNzsz  
catch(Exception e){e.printStackTrace ();} 3pI)  
} 299uZz}Y  
%n:ymc $}  
pl5Q2zq%  
//获得文件长度 @rt}z+JF  
public long getFileSize() W,sPg\G 3  
{ UWg+7RL  
int nFileLength = -1; <%EjrjdvL+  
try{ C+X- Cp  
URL url = new URL(siteInfoBean.getSSiteURL()); 6eHw\$/  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); u^]Z{K_B  
httpConnection.setRequestProperty("User-Agent","NetFox"); I=}pT50~9  
Q[UYNQ0w  
8PwPI%Pb  
int responseCode=httpConnection.getResponseCode(); 2)47$eu  
if(responseCode>=400) o&U/e\zy  
{ Cy'! >  
processErrorCode(responseCode); G.sf>.[  
return -2; //-2 represent access is error 3IDX3cM9  
} -q}I; cH  
:dj=kuUTbu  
YTYCv7  
String sHeader; e? n8S  
%][6TZ}  
t[Ywp!y[  
for(int i=1;;i++) *d$r`.9j  
{ xm bFJUMH  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Xe>   
//Utility.log(in.readLine()); H|/U0;s  
sHeader=httpConnection.getHeaderFieldKey(i); _/)HAw?k  
if(sHeader!=null)  _V_GdQ  
{ Jw)-6WJ!uO  
if(sHeader.equals("Content-Length")) }@Ou]o  
{ A<<Bm M.%  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); `]4bH,%~  
break; i $;y  
} 7=[/J*-m  
} R?H[{A X  
else =>,X)+O  
break;  NncII5z  
} %6HJM| {H  
} k9 NPC"  
catch(IOException e){e.printStackTrace ();} V { yk  
catch(Exception e){e.printStackTrace ();} Tl`HFZQ1  
f4r)g2Zb[  
mZ}C)&,m2  
Utility.log(nFileLength); [V_\SQV0  
+DA ,|~k_  
pQ yH`  
return nFileLength; R1NwtnS  
} Q9NKQuSu  
-VhxnhS  
@86?!0bt  
//保存下载信息(文件指针位置) QPJz~;V2  
private void write_nPos() g.d~`R@v  
{ TxXX}6  
try{ i :Sih"=  
output = new DataOutputStream(new FileOutputStream(tmpFile)); El4SL'E@  
output.writeInt(nStartPos.length); BhC>G2 ^7  
for(int i=0;i<nStartPos.length;i++) !+Us)'L  
{ e]@R'oM?#`  
// output.writeLong(nPos); I2^ Eo5'  
output.writeLong(fileSplitterFetch.nStartPos);  @bO/5"X,  
output.writeLong(fileSplitterFetch.nEndPos); Y!w {,\3  
} (|U|>@  
output.close(); z< ,rE  
} KB6`OT^b{r  
catch(IOException e){e.printStackTrace ();}  _)=eE  
catch(Exception e){e.printStackTrace ();} ,ou&WI yC  
} w-?|6I}T  
 ua] ?D2  
ry!0~ir  
//读取保存的下载信息(文件指针位置) zaMKwv}BR  
private void read_nPos() o%.0@W  
{ YH/3N(],  
try{ VAet!H+]  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); yy#4DYht  
int nCount = input.readInt(); FCA]zR1  
nStartPos = new long[nCount]; 2}jC%jR2  
nEndPos = new long[nCount]; }Z3+z@L  
for(int i=0;i<nStartPos.length;i++) *#g[ jl4  
{ Z@ZSn0  
nStartPos = input.readLong(); \:|"qk  
nEndPos = input.readLong(); @w{"6xc%a  
} o0\d`0-el  
input.close(); 2V)qnMxAZJ  
} "Iwd-#;$;  
catch(IOException e){e.printStackTrace ();} ^U[yk'!Y  
catch(Exception e){e.printStackTrace ();} ~fR-cXj"  
} /XZ\Yy=  
Xw |6 #^  
L+J)  
private void processErrorCode(int nErrorCode) cOo@UU P   
{ ] R-<v&O  
System.err.println("Error Code : " + nErrorCode); mqk tM6  
} n06Jg+  
B[B(=4EzMP  
mdy+ >e <  
//停止文件下载 6BIr{SY  
public void siteStop() }hA h'*(  
{ 9G=HG={  
bStop = true; CWW|?  
for(int i=0;i<nStartPos.length;i++) v!77dj 6I  
fileSplitterFetch.splitterStop(); 85 <%L:EC  
MMS#Ci=Lj  
| +r5D4]e  
} [&h%T;!Qii  
} 1J @43>u{  
//负责部分文件的抓取 :elTqw>pn  
**FileSplitterFetch.java 7zEpuw  
*/ Zq\Vq:MX  
package NetFox; Q3|I.I e  
z)0%gd|  
$mLiEsJ  
import java.io.*; I^itlQ  
import java.net.*; BOf)27)  
#) bqn|0l  
fOkB|E]  
public class FileSplitterFetch extends Thread { j O6yZt  
\\i$zRi  
/o]j  
String sURL; //File URL vQhi2J'  
long nStartPos; //File Snippet Start Position ruK, Z,3Q  
long nEndPos; //File Snippet End Position T$r?LIa ,Q  
int nThreadID; //Thread's ID qbu5aK}+  
boolean bDownOver = false; //Downing is over &p6^    
boolean bStop = false; //Stop identical +U= !svE  
FileAccessI fileAccessI = null; //File Access interface RuuXDuu:VL  
V07? sc<  
1H]E:Bq  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException &RbT&  
{ 'Bb@K[=s  
this.sURL = sURL; /woC{J)4p  
this.nStartPos = nStart; 2#g4R  
this.nEndPos = nEnd; to"[r  
nThreadID = id; F}dq~QCzw  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 $mZpX:7/u8  
} j3yz"-53e  
ZK8I f?SD  
rN5;W  
public void run() JwM Fu5@  
{ >$dkA\&p  
while(nStartPos < nEndPos && !bStop) k:k!4   
{ )'Yoii{dSU  
IWD21lS  
Fl;!'1  
try{ -|x YT+?%  
URL url = new URL(sURL); j~VHU89  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); KuohUH+  
httpConnection.setRequestProperty("User-Agent","NetFox"); .,7ZD O9{  
String sProperty = "bytes="+nStartPos+"-"; tpP2dg9dF  
httpConnection.setRequestProperty("RANGE",sProperty); [V_?`M  
Utility.log(sProperty); JHIXTy__  
"Ir.1FN  
Mh;rhQ  
InputStream input = httpConnection.getInputStream(); g1zX^^nd,V  
//logResponseHead(httpConnection); "}'Sk(  
Q]NGd 0J  
H]JVv8  
byte[] b = new byte[1024]; #Y'svn1H  
int nRead; 2*1FW v  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) D|rcSa.M  
{ <"rckPv_H  
nStartPos += fileAccessI.write(b,0,nRead); &6}] v:  
//if(nThreadID == 1) z~+gche>  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Qpaan  
} E+|r h-M7  
vspub^;5\  
8 y+Nl&"V  
Utility.log("Thread " + nThreadID + " is over!");  }j /r  
bDownOver = true; Q($aN-   
//nPos = fileAccessI.write (b,0,nRead); 2lm{:tS  
} baL-~`(T  
catch(Exception e){e.printStackTrace ();}  e+=IGYC  
} Y^P'slY{%  
} b/g"ws_  
l5bd);L tq  
^vH3 -A;*  
//打印回应的头信息 SuU %x2  
public void logResponseHead(HttpURLConnection con) b$Ch2Qz0q  
{ 6a\YD{D] _  
for(int i=1;;i++) dx It.h   
{ `GD>3-   
String header=con.getHeaderFieldKey(i); _$Hx:^p:  
if(header!=null) KB^i=+xr  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); |#D$9+  
Utility.log(header+" : "+con.getHeaderField(header)); wBK%=7  
else uRu)iBd D  
break; M$Of.  
} )-4xI4  
} b+`mh  
>4lT0~V/  
_Z|3qQ  
public void splitterStop() rJ UXA<:2  
{ ]A2l%V_7  
bStop = true; V*U*_Y  
} :*wjC.Z  
_hb@O2f  
;uazQyo6  
} t%f6P  
%95'oW)lo  
U'tfsf/V  
/* 0 w#[?.  
**FileAccess.java Sn lKPd  
*//文件访问(定位,写) &R "Q  
package NetFox; A+Xk=k5<  
import java.io.*; #=hI}%n  
@]0;aZ{3  
<_tkd3t#W  
public class FileAccessI implements Serializable{ 7~V,=WEe  
dq{wFI)  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 AqzPwO^  
RandomAccessFile oSavedFile; }`,}e259  
long nPos; !7O!)WJ  
"""gV)Y  
utvZ<zz`  
public FileAccessI() throws IOException 2"~QI xY=  
{ oT\u^WU  
this("",0); -b4#/q+bb+  
} LJ|2=lI+jb  
e:~r_,K  
iJrF$Xw  
public FileAccessI(String sName,long nPos) throws IOException !L#>wlX)  
{ 1*"t-+|  
oSavedFile = new RandomAccessFile(sName,"rw"); oVLgHB\zL  
this.nPos = nPos; :OVre*j  
oSavedFile.seek(nPos); =a<};X  
} &l=%*`On  
M=hH:[6 &  
>7VO ytc  
public synchronized int write(byte[] b,int nStart,int nLen) uWYI p\NN  
{ hK,e<?N^  
int n = -1; G Uf[Dz  
try{ (1pxQ%yEA  
oSavedFile.write(b,nStart,nLen); UtF8T6PKdW  
n = nLen; 7X$[E*kd  
} dT%$"sj5  
catch(IOException e) DUk&`BSJ  
{ LH4!QDK-  
e.printStackTrace (); -o8H_MR  
} wW~y?A"{2  
q}PeXXH  
H?~|Uj 6  
return n; zw`T^N#  
} c7[<X<yk  
0Jh^((i*  
1 XAXokxj  
} Gyak?.@R  
:K ^T@F5n  
=7JvS~s  
/* s0 ZF+6f  
**SiteInfoBean.java J2$L[d^  
*/ *Op;].>E  
package NetFox; >[=fbL@N<@  
^ 2"r't  
nVF?.c  
public class SiteInfoBean { Dk!;s8}*c  
+mQMzZZTZ  
9y(75Bn9  
private String sSiteURL; //Site's URL R&cOhUj22J  
private String sFilePath; //Saved File's Path 37hs/=x  
private String sFileName; //Saved File's Name R#ABda9  
private int nSplitter; //Count of Splited Downloading File GHaOFLY  
.a%D:4GYR  
,Jy@n]x  
public SiteInfoBean() +!'\}"q  
{//nSplitter的缺省值为5 vps</f!  
//default value of nSplitter is 5 v2e*mNK5  
this("","","",5); =l_B58wrx  
} )uvs%hK  
[*<F   
d%:B,bck  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 2NHkK_B1P  
{ M^c`j#NQ  
sSiteURL= sURL; U{vt9t  
sFilePath = sPath; g]IRv(gDh  
sFileName = sName; la7VeFT  
this.nSplitter = nSpiltter; RKu'WD?sdH  
2sj[hI  
I%]~]a  
} jN\} l|;q  
'u6T^YS  
mXd,{b'  
public String getSSiteURL() PuvC MD  
{ Y40`~  
return sSiteURL; &@tD/Jw3  
} :a M ZJm  
*f%uc  
si:p98[w  
public void setSSiteURL(String value) UEZnd8  
{ p5|.E  
sSiteURL = value; v=kQ / h  
} -}u=tiNG  
R?)M#^"W  
Mu,}?%  
public String getSFilePath() !_Z\K$Ns  
{ l<5@a (  
return sFilePath; `0 .<  
} Y}<w)b1e|  
6w3z&5DY|  
D00I!D16  
public void setSFilePath(String value) !~+"TI}_%w  
{ 'R&Y pR  
sFilePath = value; X]^FHYjhS  
} )-D{]>8  
C` s  
; B4x>  
public String getSFileName() ldd|"[Ds  
{ ]ZV.@% +  
return sFileName; v6Vieo=  
} P9Ye e!*H  
CH!>RRF  
S$ u`)BG):  
public void setSFileName(String value) Wpgp YcPS  
{ HeV6=&#  
sFileName = value; @>>8CU^~  
} Y?ADM(j  
+#%#QL  
BE`{? -G  
public int getNSplitter() [1+ o  
{ F1m 1%  
return nSplitter; :@mBSE/  
} 0GEM3~~D.?  
Q"o* \I  
!*[Fw1-J  
public void setNSplitter(int nCount) lD`@{A  
{ tM&O<6Y  
nSplitter = nCount; Ri[ v(Zf  
} /y8=r"'G  
} 7Cx*Ts$  
!V<c:6"  
\<cs:C\h7  
/* 0\qLuF[)  
**Utility.java >XTDN  
*/ I},]Y~Y3  
package NetFox; MHl ffj  
MR=dQc  
|p4D!M+$7  
public class Utility { %y7&~me  
]2:w?+T  
UweXz.x7  
public Utility() QCm93YZs6E  
{  "! -  
7T\LYDT  
gu~JB  
} rM?O2n  
:6}Zo  
//线程睡眠 Q9Tt3h2ga  
public static void sleep(int nSecond) = aO1uC|6C  
{ kn$2_I9  
try{ x9QUo*MT  
Thread.sleep(nSecond); y\a@'LFL  
} t@#+vs@  
catch(Exception e) 5 )A(q\  
{ XZh1/b^DMN  
e.printStackTrace (); w^{qut.  
} 9i6z  p'  
} $-J0ou8~  
rI'kGqU  
//日志 ^bD)Tg5K  
public static void log(String sMsg) *Z9Rl>  
{ D)O2=aQ;]  
System.err.println(sMsg); p`+=) n  
} [8kufMY|  
'P AIh*qA  
!6` pq  
public static void log(int sMsg) n]%T>\gw  
{ 5L?_AUL  
System.err.println(sMsg); `\p5!Iq Q  
} c @U\d<{w  
} W"{:|'/v  
i1c z+}  
Quq X4  
/* i% FpPni  
**TestMethod.java [Sj _=  
*/ a)o-6  
package NetFox; q0m> NA   
. r?URC  
e(z'u A{!  
public class TestMethod { ]QJ N` ;b0  
w\K(kNd(  
Wr j<}L|  
public TestMethod() 5bj9S  
{ ///xx/weblogic60b2_win.exe  Zra P\?  
try{ pu"m(9  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 3+<f7  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); r(ZMZ^  
SiteFileFetch fileFetch = new SiteFileFetch(bean); kndN} Vq  
fileFetch.start(); >D\jyd$wh&  
} mXSs:FqE!  
catch(Exception e){e.printStackTrace ();} 7hzd.  
c,yjsxETW  
J4) ?hS  
} >h Rq  
t}Q PPp y  
\yE*nZ  
public static void main(String[] args) &6@# W]_  
{ MnPk+eNJm  
new TestMethod(); yq=rv$.s  
} |34M.YjA  
} 5/E7@h ,  
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