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http断点续传简单实现(java)

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/* c'b,=SM  
**SiteFileFetch.java (P?9Jct  
*/ U,'n}]=4A3  
package NetFox; \IKr+wlN8  
import java.io.*; y.zQ `  
import java.net.*; :R)IaJ6)  
\1Zf Sc  
+-hmITJ v  
public class SiteFileFetch extends Thread { {% P;O ?  
X 6)LpMm  
{8' 5  
SiteInfoBean siteInfoBean = null; //文件信息Bean -Q; w4@  
long[] nStartPos; //开始位置 L$g;^@j  
long[] nEndPos; //结束位置 rhrlEf@  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 QUt!fF@t  
long nFileLength; //文件长度 g=)@yZ3>v  
boolean bFirst = true; //是否第一次取文件 =F9-,"EAI  
boolean bStop = false; //停止标志 yC[}gHv  
File tmpFile; //文件下载的临时信息 R:Lu)d>=  
DataOutputStream output; //输出到文件的输出流 *b&|  
y.zW>Mfl  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) \m<*3eS  
public SiteFileFetch(SiteInfoBean bean) throws IOException 6vDgM fw  
{ yxH[uJpb  
siteInfoBean = bean; w^~,M3(+)1  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 8:f( PN  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); PYZ8@G  
if(tmpFile.exists ()) 9I,Trk@&  
{ uZfo[_g0S  
bFirst = false; ,-):&V:jF  
read_nPos(); b{A#P?  
} k@?<Aw8 _X  
else =_5-z|<  
{ n'SnqJ&}  
nStartPos = new long[bean.getNSplitter()]; Qi9SN00F.  
nEndPos = new long[bean.getNSplitter()]; "h "vp&A  
} zQ6otDZx  
o!Y7y1$  
oZQu&O'  
.A E(D7d6  
} S;Vj5  
7z}NI,R}1  
v''$qMQ)  
public void run() =7a9~&|  
{ $(BW |Pc  
//获得文件长度 L~\Ir  
//分割文件 -{HA+YL H  
//实例FileSplitterFetch V[#jrwhA  
//启动FileSplitterFetch线程 bYiaJ  
//等待子线程返回 *t63c.S  
try{ s q_ f[!  
if(bFirst) /)j:Y:5  
{ gF&1e5`i  
nFileLength = getFileSize();  [5H#ay  
if(nFileLength == -1) ^5OR%N)  
{ )Zox;}WK+  
System.err.println("File Length is not known!"); KrB"2e+J  
} 3{CXIS  
else if(nFileLength == -2) y\S}U{*Z'  
{ q.*k J/L  
System.err.println("File is not access!"); WOh?/F[@u  
} 'bTtdFvJ  
else dW6sA65<Y  
{ ^I7iEv  
for(int i=0;i<nStartPos.length;i++) +Y-Gp4"  
{ jx J5F3d  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); U 1vZ r{\  
} 09/Mg  
for(int i=0;i<nEndPos.length-1;i++) `Ps&N^[  
{ 13kl\ <6  
nEndPos = nStartPos[i+1]; EjrK.|I0  
} H>X:#xOA_  
nEndPos[nEndPos.length-1] = nFileLength; ';Y0qitGB  
} ]v=A}}kS  
} 7*.nd  
]De<'x}  
''tCtG" Xi  
//启动子线程 Fsz;T;  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; MaN6bM  
for(int i=0;i<nStartPos.length;i++) ,N93H3(  
{ u^, eHO  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Y'*oW+K  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), g%TOYZr!X  
nStartPos,nEndPos,i); uVN2}3!)Y  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); l|v`B6(  
fileSplitterFetch.start(); >P@g].Q-  
} !Ah v07SI  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ~bf4_5  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); X lLG/N  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 5If.[j{  
nEndPos = " + nFileLength); *O_>3Hgl  
// fileSplitterFetch[nPos.length-1].start(); F/V -@SF  
6 dgwsl~  
`3g5n:"g\  
//等待子线程结束 #zRHYZc'T|  
//int count = 0; 9:R3+,ZN  
//是否结束while循环 $7" Y/9Y  
boolean breakWhile = false; C~Hhi-Xl)  
r3  qKT  
^hNl6)hR  
while(!bStop) >v2/0>U  
{ SSxp!E'  
write_nPos(); .do8\  
Utility.sleep(500); |M`'   
breakWhile = true; PriLV4?  
bmu]zJ  
zZ6m`]{B9?  
for(int i=0;i<nStartPos.length;i++) 3^[P  
{ eR%\_;}7;  
if(!fileSplitterFetch.bDownOver) Om^(CAp  
{ 9U8x&Z]P  
breakWhile = false; 3\2%i 6W6  
break; @R%* ;)*F  
} vJxE F&X  
} nNq<x^@83  
if(breakWhile) <8(=Lv`)q  
break; !B 4zU:d  
d?&`Z Vl  
,Kl:4 Tv  
//count++; nfbR"E jXr  
//if(count>4) KCO.8=y3  
// siteStop(); ynv{ rMl  
} GF6o  
TG[u3 Y4  
<pfl>Uf  
System.err.println("文件下载结束!"); -w*fS,O  
} f";pfu_FZ  
catch(Exception e){e.printStackTrace ();} D%~tU70a  
} hs[x\:})/  
FY^2 Y  
:`e#I/,  
//获得文件长度 _aR{B-E  
public long getFileSize() }[Z'Sg]s  
{ j*@@H6G  
int nFileLength = -1; Ym 1vq=  
try{ 4XNheP;b  
URL url = new URL(siteInfoBean.getSSiteURL()); w%.hALN5-C  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); kN.;;HFq#  
httpConnection.setRequestProperty("User-Agent","NetFox"); qmFG  
5]>*0#C S  
N]w_9p~=1  
int responseCode=httpConnection.getResponseCode(); ?OLd }8y  
if(responseCode>=400) ]R_R`X?  
{ x>}ml\R  
processErrorCode(responseCode); 7b+r LyS0  
return -2; //-2 represent access is error r5DR F4,7  
} tsAV46S  
SK lvZ  
W w,\s5Uw  
String sHeader; 3Rc*vVnI  
S[1<Qrv]  
;.V/ngaj  
for(int i=1;;i++) l::q F 0  
{ =SXdO)%2  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 2 ^m}5:0  
//Utility.log(in.readLine()); j:h}ka/!p  
sHeader=httpConnection.getHeaderFieldKey(i); Fp/{L  
if(sHeader!=null) +P^ ;7"H  
{ D`T;j[SsS#  
if(sHeader.equals("Content-Length")) F{0\a;U@^  
{ wAKHD*M)  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); jc&k-d>=G  
break; '{"Rjv7  
} ;cXw;$&D  
} qD{1X25O  
else ~Q&J\'GQH  
break; KLyRb0V  
} A`n>9|R  
} --WQr]U/  
catch(IOException e){e.printStackTrace ();} iApq!u,  
catch(Exception e){e.printStackTrace ();} 4rU/2}. q  
~w? 02FU  
w}ji]V}  
Utility.log(nFileLength); ~[HzGm%  
B&]`OO>O  
k7^hc th  
return nFileLength; BS9VwG <Z  
} ZwkUd-=0i  
n93q8U6m/U  
zMsup4cl  
//保存下载信息(文件指针位置) DZSS  
private void write_nPos() pey=zR!  
{ aKDY_ D  
try{ iFd !ED  
output = new DataOutputStream(new FileOutputStream(tmpFile)); KqK]R6>  
output.writeInt(nStartPos.length); *?FVLE  
for(int i=0;i<nStartPos.length;i++) /65YHXg,  
{ )9hqd  
// output.writeLong(nPos); lq-KM8j  
output.writeLong(fileSplitterFetch.nStartPos); Lc{AB!Br  
output.writeLong(fileSplitterFetch.nEndPos); /eV)5`V  
} Anz{u$0M[  
output.close(); d4| )=  
} Tn&_ >R  
catch(IOException e){e.printStackTrace ();} y b hFDx  
catch(Exception e){e.printStackTrace ();} !"N,w9MbD  
} W'C>Fn}lO?  
@IL04' \  
|'h (S|  
//读取保存的下载信息(文件指针位置) N3%#JdzZ$  
private void read_nPos() _%e8GWf  
{ bf_ > ?F^  
try{ ,Kv6!ib6Q  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 3"h*L8No  
int nCount = input.readInt(); 1#vu)a1+b  
nStartPos = new long[nCount]; 0Y8gUpe3P6  
nEndPos = new long[nCount]; mkSu $c  
for(int i=0;i<nStartPos.length;i++) %g9y m@s  
{ dla_uXtM6  
nStartPos = input.readLong(); tx09B)0  
nEndPos = input.readLong(); &W\e 5X<A  
} zDvV%+RW)  
input.close(); ,;pUBrz/[  
} 7h\is  
catch(IOException e){e.printStackTrace ();} p/{%%30ke  
catch(Exception e){e.printStackTrace ();} I): c#  
} G<CD 4:V  
`y>m >j  
Ic'D# m  
private void processErrorCode(int nErrorCode) YuhfPa  
{ bW`nLiw}%  
System.err.println("Error Code : " + nErrorCode); mnA_$W3~I  
} EID-ROMO  
_ s 3aaOL  
QBa+xI_ J  
//停止文件下载 PhAfEsD  
public void siteStop() tR!C8:u  
{ p*<Jg l  
bStop = true; >#h,q|B  
for(int i=0;i<nStartPos.length;i++) XJo.^<m  
fileSplitterFetch.splitterStop(); H,D5)1Uu  
;r@=[h   
@fA{;@N  
} 3HyOQD"{  
} T={!/y+  
//负责部分文件的抓取 !$NK7-  
**FileSplitterFetch.java 8=D,`wog  
*/ Y2VfJ}%Q  
package NetFox; ?b7ttlX{  
9,8/DW.K  
Wrp~OF0k  
import java.io.*; nReIi;pi  
import java.net.*; -3ePCAtXbe  
4rDV CXE  
T'6`A<`3  
public class FileSplitterFetch extends Thread { jTS8 qu  
;8<HB1 &,  
6D| F1UFU  
String sURL; //File URL E,d<F{=8,o  
long nStartPos; //File Snippet Start Position GG%;~4#2  
long nEndPos; //File Snippet End Position 53hX%{3  
int nThreadID; //Thread's ID w7` pbcY,  
boolean bDownOver = false; //Downing is over  dw;<Q  
boolean bStop = false; //Stop identical t;+b*S6D  
FileAccessI fileAccessI = null; //File Access interface [.&JQ  
 3*Q=)}  
a( ~X  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException nP[Z6h  
{ v2tVq_\AMx  
this.sURL = sURL; J#Q>dC7  
this.nStartPos = nStart; E-1u_7  
this.nEndPos = nEnd; H*G(`Zl}  
nThreadID = id; }J?,?>Z  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 .(/HUQn  
} 'Ev[G6vo  
}8AH/  
dG+$!*6Z  
public void run() \5tG>>c i  
{ y_>DszRN`u  
while(nStartPos < nEndPos && !bStop) BEax[=&W  
{ R<f F ^^  
&~;M16XM,e  
!e<5JO;c  
try{ e<uf)K=(C  
URL url = new URL(sURL); ^>%.l'1/(  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ` Ft-1eE  
httpConnection.setRequestProperty("User-Agent","NetFox"); %7 -(c  
String sProperty = "bytes="+nStartPos+"-"; '0 ~?zP  
httpConnection.setRequestProperty("RANGE",sProperty); E5A"sB   
Utility.log(sProperty); _"x%s  
@H$8;CRM  
4<tbZP3/6)  
InputStream input = httpConnection.getInputStream(); \^0>h`[  
//logResponseHead(httpConnection); v .*fJ   
0t7)x8c  
F3vywN1$,  
byte[] b = new byte[1024]; 6|'7Mr~\  
int nRead; `3jwjy| 5  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) _QHk&-Lp  
{ ] 7[#K^  
nStartPos += fileAccessI.write(b,0,nRead); Ohgu*5!o  
//if(nThreadID == 1) SVZ@'X\[M  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); $,O8SW.O$  
} O13]H"O_  
a e-tAA[1Y  
Lj|wFV  
Utility.log("Thread " + nThreadID + " is over!"); zOA~<fhT  
bDownOver = true; &HLG<ISw  
//nPos = fileAccessI.write (b,0,nRead); [;aM8N  
} F,)+9/S&  
catch(Exception e){e.printStackTrace ();} QKEtV  
} WI| -pzg  
} &Jb$YKt  
AvZ5?rN$  
BUwL?  
//打印回应的头信息 E@otV6Wk[@  
public void logResponseHead(HttpURLConnection con) JFc, f  
{ 2gklGDJD  
for(int i=1;;i++)  |15!D  
{ XPf{R619  
String header=con.getHeaderFieldKey(i); d3\?:}o,  
if(header!=null) 'Q=)-  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); XXX y*/P  
Utility.log(header+" : "+con.getHeaderField(header)); K"t?  
else t90M]EAV  
break; |*w)]2B l  
} j 7:r8? G  
} [ *It' J^  
2<OU)rVE4  
3 eF c  
public void splitterStop() @",#'eC"  
{ ,<K+.7,)E  
bStop = true; e<{ d{  
} {T^D&i# o  
d])ctxB  
{R63n  
} ?[bE/Ya+S  
B*}]'  
U5-8It2OR  
/* {Mb<on W  
**FileAccess.java  *p9)5  
*//文件访问(定位,写) o ~y{9Q  
package NetFox; XRkUv>Yk  
import java.io.*; )lt1I\n*k  
;CS[Ja>e  
*2~WP'~PQd  
public class FileAccessI implements Serializable{ hR0a5   
l,Y5VGiH#  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 mX.mX70|J  
RandomAccessFile oSavedFile; W //+[  
long nPos; x.t&NP^V)  
=$bF[3D  
>Ho=L)u  
public FileAccessI() throws IOException 4?@#w>(  
{ 'xai5X  
this("",0); iNl<<0a  
} 8;"%x|iBoL  
t>%b[(a  
v,Z]Vqk  
public FileAccessI(String sName,long nPos) throws IOException D}}?{pe  
{ \fC;b"j  
oSavedFile = new RandomAccessFile(sName,"rw"); k0PwAt)65  
this.nPos = nPos; 8Vn   
oSavedFile.seek(nPos); KK >j V  
} WdS1v%  
A0A|cJP  
]Z\W%'q+  
public synchronized int write(byte[] b,int nStart,int nLen) '>1M~B  
{ KLG.?`h:  
int n = -1; Rl0"9D87z  
try{ [ywF!#'){  
oSavedFile.write(b,nStart,nLen); euT=]j  
n = nLen; Cb<7?),vK  
} 3l`"(5  
catch(IOException e) 2<n 18-|OQ  
{ P%yL{  
e.printStackTrace (); ljrJC  
} nIBeZof  
yr>J^Et%_  
.i_ gE5  
return n; KgD$P(J:[  
} rDwd!Jet  
B/lIn' =  
"N &ix*($  
} qR2cRepV  
.^F&6'h1H  
G] tT=X[  
/* %j17QD8  
**SiteInfoBean.java BIx*(  
*/ d!&LpODI]*  
package NetFox; +N,Fq/x  
twldwuN  
 FO!0TyQ  
public class SiteInfoBean { tQ'R(H`  
Dvz 6 E  
.uX(-8n ~  
private String sSiteURL; //Site's URL 3 Z SU^v  
private String sFilePath; //Saved File's Path ';v2ld 9  
private String sFileName; //Saved File's Name (qc <'$o  
private int nSplitter; //Count of Splited Downloading File P*?2+.  
JDnWBEV  
u\xrC\Ka  
public SiteInfoBean() 5gx;Bp^_  
{//nSplitter的缺省值为5 Fgwe`[  
//default value of nSplitter is 5 3~WI3ZIR  
this("","","",5); Eqny'44  
} +dq2}gM  
>c:nr&yP  
A~?)g!tS<  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) d@Bd*iI<  
{ J$jLGy&'  
sSiteURL= sURL; /-@F|,O)$n  
sFilePath = sPath; 8BS Nm  
sFileName = sName; (l2n%LL]*  
this.nSplitter = nSpiltter; ~$ ?85   
jgpF+V-n$  
[["eK9 }0  
} XNvlx4  
KV{  
5?j#  
public String getSSiteURL() y?}<SnjP:  
{  mSFA i  
return sSiteURL; "x_G6JE4tv  
} VeFfkg4  
KUq(&H7  
pwVGe|h%,  
public void setSSiteURL(String value) g6 SZ4WV  
{ NZ^hp\q  
sSiteURL = value; YB{'L +Wbw  
} 9I1`*0A  
e5n"(s"G*[  
ldaT: er9  
public String getSFilePath() VF<VyWFC0`  
{ VjiwW%UOM  
return sFilePath; CA/Lv{[2  
} XzBl }4s  
KC<K*UHPAH  
Fl==k  
public void setSFilePath(String value) m{yq.H[X  
{ e&<=+\ul  
sFilePath = value; WZbRR.TxO  
} '?mky,:HT  
 `7V'A  
niPqzi  
public String getSFileName() =AuxME g  
{ l>7?B2^<E  
return sFileName; CT=5V@_u\  
} W=K+kB  
catJC3  
jyRz53  
public void setSFileName(String value) j'SGZnsy*  
{ Ht~YSQ~:y  
sFileName = value; ,YrPwdaTB  
} 8/|1FI  
J>0RN/38o  
qi1#s,  
public int getNSplitter() V67<Ky>  
{ &:=[\Ws R  
return nSplitter; <ZoMKUuB  
} C^ ~[b o  
xHn "D@  
zgSv -h+f  
public void setNSplitter(int nCount) Lyjp  
{ `{nzw$  
nSplitter = nCount; QLH6Nmk  
} &WVRh=R  
} JZ"XrS0?  
chU,));F  
8-Z|$F"  
/* o5w =  
**Utility.java  11-?M  
*/ 4~0 @(3  
package NetFox; CN#2-[T  
9P-I)ZqL  
8wzQr2:  
public class Utility { TI637yqCU  
(0 S;eM&  
g;</|Z  
public Utility() 9Qc=D"'  
{ vb]H $@0  
]Cc8[ZC  
-Rr Qv(  
} A!_yZ|)$ T  
q<Wz9lDMNR  
//线程睡眠 )9V8&,  
public static void sleep(int nSecond) j:J7  
{ KA]5tVQA  
try{ pm'i4!mY<P  
Thread.sleep(nSecond); G/_9!lE  
} NAEAvXj  
catch(Exception e) )E=~ _`XO  
{ TM`6:5ONv  
e.printStackTrace (); o<i\1<eI  
} "v5jYz5M  
} Zl=IZ?F   
N/eFwv.Er  
//日志 q-d#bKIf  
public static void log(String sMsg) 4[f>kY%[  
{ !wEz= i  
System.err.println(sMsg); -jL10~/  
} iea7*]vW  
=s h]H$  
0^zp*u  
public static void log(int sMsg) 5$"I Uq*  
{ pwr]lV$w  
System.err.println(sMsg); \kVi&X=q:  
} |j~{gfpSE  
} {&s.*5  
=&v&qn e9  
5TVA1  
/* ?<eH!MHF  
**TestMethod.java aj@<4A=;  
*/ J={IGA  
package NetFox; )w&k&TY4H  
8YwSaBwO  
2f7]= snCG  
public class TestMethod { nM6/c  
n~G-X  
" )/febBS  
public TestMethod() dI$M9;  
{ ///xx/weblogic60b2_win.exe "o>gX'm*  
try{ @DA.$zn&  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); {{ /-v3n  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); EiWsVic[  
SiteFileFetch fileFetch = new SiteFileFetch(bean); CWS&f g%o{  
fileFetch.start(); /yO|Q{C}M8  
} 4]%v%6 4U  
catch(Exception e){e.printStackTrace ();} #a=~a=c(^  
*HXx;:  
s2Hx ?~  
} "qvJ-Y  
>'96SE3  
\?rBtD(  
public static void main(String[] args) !Xf7RT  
{ iP^o]4[c  
new TestMethod(); T9=55tpG9  
} :ZP`Y%dt'  
} >pq= .)X}  
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