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http断点续传简单实现(java)

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/* P26"z))~d  
**SiteFileFetch.java cdN=HM~I  
*/ )iJv?Y\]  
package NetFox; xz~Y %Y|Z  
import java.io.*; av_ +M;G  
import java.net.*; Z@bSkO<Y  
{gxP_>  
#N;&^El  
public class SiteFileFetch extends Thread { h^,av^lg^  
SXC 7LJm<g  
&Mz]y?k'  
SiteInfoBean siteInfoBean = null; //文件信息Bean Ro;I%j  
long[] nStartPos; //开始位置 R:rols"QM  
long[] nEndPos; //结束位置 @<&u;8y-Cn  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 6  $`l  
long nFileLength; //文件长度 .@ZrmO o]]  
boolean bFirst = true; //是否第一次取文件 5vLA)Al3  
boolean bStop = false; //停止标志 Mcq!QaO}&  
File tmpFile; //文件下载的临时信息 < FY%QB)h  
DataOutputStream output; //输出到文件的输出流 {vT9I4d8  
'dqecmB  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) )i_:[ l6  
public SiteFileFetch(SiteInfoBean bean) throws IOException D G|v' #  
{ IyM:9=}5  
siteInfoBean = bean; qC5IV}9`  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); yF1p^>*ak&  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); lBa` nG  
if(tmpFile.exists ()) xZY7X&C4  
{ $R+rB;=a!  
bFirst = false; <AK9HPxP  
read_nPos(); .Hk.'>YR  
} R7KV @n  
else $<"I*l@  
{  y(#6nG@S  
nStartPos = new long[bean.getNSplitter()]; o' v!83$L  
nEndPos = new long[bean.getNSplitter()]; yivWT;`  
} ~SmFDg$/m  
xu{VU^'Y  
7fXJP5j  
)1YX+',"  
} 2.\"Q  
Y/?z8g'p  
\#IKirf?  
public void run() 3`)ej`  
{ G&t|aY-   
//获得文件长度 7#SfuZ0@  
//分割文件 x&"P^gh)  
//实例FileSplitterFetch p/G9P +?  
//启动FileSplitterFetch线程 5m;BL+>YE  
//等待子线程返回 KUpj.[5 qo  
try{ g9=_^^Tg  
if(bFirst) \}X[0ct2!  
{ > 6=3y4tP  
nFileLength = getFileSize(); ^ 8YBW<9  
if(nFileLength == -1) |>1#)cONW  
{ Cs\jPh;"  
System.err.println("File Length is not known!"); dpX Fx"4A  
} H}q$6W E  
else if(nFileLength == -2) )3<>H!yG}  
{ !R gj'{  
System.err.println("File is not access!"); mD|Q+~=|e  
} dK0H.|  
else i29a1nD4Hm  
{ 9p1@Lfbj  
for(int i=0;i<nStartPos.length;i++) >&k`NXS|V  
{ $=`d[04  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); - P "  
} YLS*uXB&.  
for(int i=0;i<nEndPos.length-1;i++) $My~sN8  
{ t*dq*(3"c  
nEndPos = nStartPos[i+1]; a7=lZZ?  
} !6z{~Z:   
nEndPos[nEndPos.length-1] = nFileLength; B@#vS=g  
} r'lANl-v  
} 0{u%J%;  
NjPQT9&3h  
AX Q.E$1g  
//启动子线程 I*$-[3/  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; d+6q% U  
for(int i=0;i<nStartPos.length;i++) mIPDF1= )  
{ $RunGaX!=N  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), KD\sU6  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), \ H#"  
nStartPos,nEndPos,i); TA qX f_  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Z[B:6\oQ  
fileSplitterFetch.start(); tR2%oT>h  
} l2YA/9.  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,?HM5c{'[Y  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); mNEh\4ai  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", O%6D2d  
nEndPos = " + nFileLength); u} +?'B)  
// fileSplitterFetch[nPos.length-1].start(); FvO,* r9  
Oi]B%Uxy=  
fVVD}GM=  
//等待子线程结束 P,xJVo\  
//int count = 0; =BJe}AV  
//是否结束while循环 b TZ.y.sI  
boolean breakWhile = false; atmW? Z  
.:GOKyr(~  
#{^qBP[  
while(!bStop) !H<%X~|,  
{ y y[Y=  
write_nPos(); YU!s;h  
Utility.sleep(500); BjA$^i|8  
breakWhile = true; SXN]${  
@1<VvW=  
0\s&;@xKk  
for(int i=0;i<nStartPos.length;i++) ^,)nuU y  
{ bI_MF/r''  
if(!fileSplitterFetch.bDownOver) @; I9e  
{ #!%zf{(C+  
breakWhile = false; Oamz>Hplu  
break; <G`1(,g  
} }' s W[?ik  
} 1L!jI2~x}  
if(breakWhile) `e?~c'a@  
break; O: #Sj jK  
r* l c#  
lV$#>2Hh5  
//count++; ckv8QAm  
//if(count>4) $<Y%4LI  
// siteStop(); jzZ]+'t  
} 8OO[Le]1  
U0srwt97S  
&\Lu}t7Ru  
System.err.println("文件下载结束!"); ZLPj1L  
} c@)?V>oe  
catch(Exception e){e.printStackTrace ();} &%8IBT  
} }$r]\v  
N93R(x)%  
n}fV$qu  
//获得文件长度 TeO'E<@  
public long getFileSize() K5\l (BB  
{ UO!} 0'  
int nFileLength = -1; e$JCak=  
try{ zr_L V_e  
URL url = new URL(siteInfoBean.getSSiteURL()); &A`,hF8  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();  Y(2Z<d  
httpConnection.setRequestProperty("User-Agent","NetFox"); Jf\`?g3#  
(0.JoeA`y  
R*XZPzg%  
int responseCode=httpConnection.getResponseCode(); yF%e)6  
if(responseCode>=400) Q<ia  
{ E*fa&G~s )  
processErrorCode(responseCode); Kp1 F"!  
return -2; //-2 represent access is error q^n LC6q  
} ;Ru[^p.{  
Y6v#0pT  
\Sv|yQUT  
String sHeader; %y*'bS  
t)g %9 k^  
`PvS+>q  
for(int i=1;;i++) XW@C_@*J  
{ `D$^SHfyz  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); o_[~{@RoR  
//Utility.log(in.readLine()); 2;3&&yK2b  
sHeader=httpConnection.getHeaderFieldKey(i); W- nS{v(  
if(sHeader!=null) fwMYEj  
{ Ro<x#Uo  
if(sHeader.equals("Content-Length")) [McqwU/Q  
{ :}/\hz ,  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); LP'q$iB!  
break; ^N 4Y*NtV7  
} g)D@4RM  
} [z+YX s!N  
else ^tWSu?9  
break; wL^x9O|`p9  
} ; C(5lD&\5  
} i[{*(Y$L  
catch(IOException e){e.printStackTrace ();}  >;%QW  
catch(Exception e){e.printStackTrace ();} lA;^c)  
+aPe)U<t  
]KXyi;n2  
Utility.log(nFileLength); 8>D*U0sNl  
]#rV]As  
E}a.qM'  
return nFileLength; 4^4T#f2=e  
} RL/7>YQ  
ua &uR7  
1/qD5 *`Y  
//保存下载信息(文件指针位置) _bg Zl  
private void write_nPos() jVN=_Y}\  
{ d(R8^v/L  
try{ Fm6]mz%~u#  
output = new DataOutputStream(new FileOutputStream(tmpFile)); GK6CnSV8d  
output.writeInt(nStartPos.length); UX.rzYM&T  
for(int i=0;i<nStartPos.length;i++) )1R[X!KQ7  
{ Tyb'p9  
// output.writeLong(nPos); riaL[4c  
output.writeLong(fileSplitterFetch.nStartPos); g}K/ba'  
output.writeLong(fileSplitterFetch.nEndPos); $=^}J 6  
} /h`gQyGuY  
output.close(); QMrH%Y  
} E?|NYu#I6  
catch(IOException e){e.printStackTrace ();} X%fLV(  
catch(Exception e){e.printStackTrace ();} !8W0XUqh+  
} CRrEs 18;#  
IB 4L(n1  
>9#) obw  
//读取保存的下载信息(文件指针位置) =?wDQ:  
private void read_nPos() QR8]d1+GV  
{ nGc'xQy0  
try{ W$J.B!O  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); _FS #~z'j  
int nCount = input.readInt(); nU\.`.39 +  
nStartPos = new long[nCount]; kApDD[ N  
nEndPos = new long[nCount]; 8oRq3"  
for(int i=0;i<nStartPos.length;i++) P c5C*{C  
{ T?=]&9Y'  
nStartPos = input.readLong(); d7zZ~n  
nEndPos = input.readLong();   uk,9N  
} In!^+j  
input.close(); b].U/=Hs  
} xXmlHo<D  
catch(IOException e){e.printStackTrace ();} eWD!/yr|  
catch(Exception e){e.printStackTrace ();} /l3Oi@\  
} Gi$\th,  
"[7'i<,AI  
\VW":+  
private void processErrorCode(int nErrorCode) qf<o"B|_9  
{ '.S02=/  
System.err.println("Error Code : " + nErrorCode); \9od*y  
} b'R]DS{8  
.W2w/RayC  
mL'A$BR`  
//停止文件下载 QyZ' %T5J  
public void siteStop() XH/!A`ZK  
{ ]*U; }  
bStop = true; Q`Pe4CrWvu  
for(int i=0;i<nStartPos.length;i++) HJpx,NU'  
fileSplitterFetch.splitterStop(); (dO0`wfM  
V|HO*HiB3  
}NdLd!  
} |o(te  
} DZb0'+jQ  
//负责部分文件的抓取 T%Zfo7  
**FileSplitterFetch.java 6Rq +=X  
*/ e},:QL0X  
package NetFox; xt`a":lru  
HL>l.IG?  
EUH9R8)  
import java.io.*; w Bm4~ ~_  
import java.net.*; s*i,Ph  
Lk^bzW>f  
Tkp"mT v?<  
public class FileSplitterFetch extends Thread { 4mX]JH`UTe  
L5 Ai  
dWwb}r(ky  
String sURL; //File URL fLSDt(c',  
long nStartPos; //File Snippet Start Position d& v 7l  
long nEndPos; //File Snippet End Position J<Ki;_=I  
int nThreadID; //Thread's ID O(.eHZ=  
boolean bDownOver = false; //Downing is over h2:TbQ  
boolean bStop = false; //Stop identical Bqk+ne  
FileAccessI fileAccessI = null; //File Access interface <+b~E,  
!A|}_K1Cr  
JPj/+f  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException %.\+j,G7  
{ >Kl_948  
this.sURL = sURL; aE"dpYQ  
this.nStartPos = nStart; =i7CF3  
this.nEndPos = nEnd; >Apa^Bp  
nThreadID = id; ATmyoN2@>  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ,5 3`t  
} iF.f*3-NJB  
uOKdb6]r6  
T`<Tj?:^&  
public void run() "15frr?  
{ 92b}N|u  
while(nStartPos < nEndPos && !bStop) "EWq{l_I5$  
{ ;9J6)zg !n  
61HJ%  
uLI;_,/:  
try{ JZ-64OT  
URL url = new URL(sURL); ?"?AH/ED  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 'C:i5?zh(q  
httpConnection.setRequestProperty("User-Agent","NetFox"); Rx.5;2m  
String sProperty = "bytes="+nStartPos+"-"; h_\W7xt  
httpConnection.setRequestProperty("RANGE",sProperty); Lc-Wf zT  
Utility.log(sProperty); )RWukr+  
UKB/>:R  
+9<:z\B|  
InputStream input = httpConnection.getInputStream(); 9 uX 15a  
//logResponseHead(httpConnection); ]Al)>  
|B^Picu  
ke/4l?zs  
byte[] b = new byte[1024]; 4)L};B=  
int nRead; PBiA/dG[;  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) FS('*w&bP  
{ ~ySsv  
nStartPos += fileAccessI.write(b,0,nRead); ZR{YpLFQ  
//if(nThreadID == 1) Lo}/k}3Sx  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _Ii=3Qsf  
} lC d\nE8G  
* $1F|G  
X>]<rEh  
Utility.log("Thread " + nThreadID + " is over!"); yRQNmR;Uy  
bDownOver = true; 2:yXeSeA  
//nPos = fileAccessI.write (b,0,nRead); X1V~.k vt)  
} hOdU%  
catch(Exception e){e.printStackTrace ();} 2G3Hi;q18  
} ^R7X!tOq4  
} YXdo&'Q<qX  
?D_}',Wx  
:."+&gb  
//打印回应的头信息 gh^w !tH3  
public void logResponseHead(HttpURLConnection con) 3 "Qg"\  
{ ?TmVLny  
for(int i=1;;i++) %?S[{ 4A&  
{ tWTC'Gx-J  
String header=con.getHeaderFieldKey(i); \3F)M`g  
if(header!=null) bIV9cpW  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Mdu\ci)lr  
Utility.log(header+" : "+con.getHeaderField(header)); ,. <c|5R  
else BcQw-<veu  
break; X%7l! k[  
} a [f}-t9  
} `\=~ $&vjC  
~!%G2E!  
<si cldz  
public void splitterStop() @;S)j!m`  
{ q+w] Xs;  
bStop = true; 6G_{N.{(  
} )M7~RN  
<9;X1XtpI  
Ngm/5Lc  
} z38Pi  
s)sT\crP@  
[DtMT6F3  
/* Z 2$S'}F  
**FileAccess.java z 5~X3k7  
*//文件访问(定位,写) Pb59RE:7V  
package NetFox; 8CvNcO;H0  
import java.io.*; m/,8\+  
GQE7P()  
A43[i@o  
public class FileAccessI implements Serializable{ *WWDwY@!u  
\vW'\}  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 {L M Q  
RandomAccessFile oSavedFile; /}5)[9GC  
long nPos; Q} g"pl  
]^@m $O  
PevT`\>  
public FileAccessI() throws IOException VZ9`Kbu  
{ VQ+G.  
this("",0); b,(<74!#8  
} v~YGef;D  
)2:U]d%pk  
6/Z_r0^O  
public FileAccessI(String sName,long nPos) throws IOException ,z+n@sUR:  
{ V.ae 5@;  
oSavedFile = new RandomAccessFile(sName,"rw"); &u (pBr8B  
this.nPos = nPos; 91k-os(4]  
oSavedFile.seek(nPos); +.*=Fn22  
} F C=N}5u  
9*r l7  
e8z?) 4T  
public synchronized int write(byte[] b,int nStart,int nLen) <DEu]-'>  
{ $bZ5@)E  
int n = -1; *I k/Vu%;  
try{ 3i9~'j;F3  
oSavedFile.write(b,nStart,nLen); jgfr_"@A  
n = nLen; e&Z ?I2J  
} A3.pz6iT>  
catch(IOException e) 1h{7dLA  
{ 5/HkhT yj  
e.printStackTrace (); QS-X_  
} /In=u6D O  
DYgz;Y/%l  
>;fn,9w  
return n; 4-C'2?  
} sAF="uB  
F-D$Y?m  
RXO5p d  
} D\pX@Sx,v[  
V7 hO}  
t ^1uj:vD  
/* +zl [C  
**SiteInfoBean.java xb&,9Lxd|  
*/ 5BM6Pnle  
package NetFox; mdcsL~R  
J{n A ?[  
)6px5Vwz  
public class SiteInfoBean { hE4qs~YB!  
\|Y_,fi  
5wv7]F<  
private String sSiteURL; //Site's URL !'Hd:oD<  
private String sFilePath; //Saved File's Path =RofC9,  
private String sFileName; //Saved File's Name m RC   
private int nSplitter; //Count of Splited Downloading File V2'5doo  
yFTN/MFt  
]Z*B17//  
public SiteInfoBean() <s'0<e!./t  
{//nSplitter的缺省值为5 65rf=*kz:  
//default value of nSplitter is 5 Mh@n>+IR  
this("","","",5); LeNSjxB  
} m'uFj !  
7{NH;U t  
C87 9eeJ  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) @r\{iSg&g.  
{ q/qig5Ou  
sSiteURL= sURL; h)z2#qfc  
sFilePath = sPath; #E_<}o  
sFileName = sName; #+|0o-  
this.nSplitter = nSpiltter; U/h@Q\~U  
akWOE}5#  
,z> w^_  
} 1L=)93,M  
8K&=]:(  
3XNk*Y[5  
public String getSSiteURL() }|Bs|$q  
{ :b;`.`@KL_  
return sSiteURL; zqp>Xw  
} EWOa2^%}Z\  
vXG?8Q  
Xu|2@?l9  
public void setSSiteURL(String value) 0(o.[% Ye  
{ h]j>S  
sSiteURL = value; ;f} ']2  
} !mUO/6Q hq  
4AKPS&k;  
<@Y`RqV+  
public String getSFilePath()  eAG)+b  
{ vD(:?M  
return sFilePath; + 7wMM#z  
} p+b$jKWQ  
Hk=HO|&<XB  
SEH[6W3  
public void setSFilePath(String value) goJ'z|))  
{ g~76c.u-  
sFilePath = value; j@{dsS: 6  
} .-Dc%ap]  
al7D3J  
$  k_6  
public String getSFileName() @\W-=YKLg  
{ NnaO!QW%  
return sFileName; K@ a#^lmd  
} xT!<x({  
QuC_sFP10  
[ B*r{  
public void setSFileName(String value) f85~[3 J  
{ )g KC}_h=  
sFileName = value; )RQQhB  
} pX1Us+%  
)c532 y  
J5Ti@(G5V  
public int getNSplitter() zU_ dk'&,  
{ %OP|%^2  
return nSplitter; Fqh./@o  
} (B! DBnq  
<-,y0Y'  
#L57d  
public void setNSplitter(int nCount) &2I8!Ia  
{ F@zTz54t  
nSplitter = nCount; Oz)/KZ  
} 6;;2e> e  
} :39arq  
MZ~N}y  
w(K|0|t  
/* 4vCUVo r  
**Utility.java .}:*tvot  
*/ 4t>"-/  
package NetFox; k$pND,Ws  
Tr;.O?@{t}  
wc&D[M]-/  
public class Utility { 7 NnXt'  
z#GSt ZT  
;<"V}, C  
public Utility() e>bARK<  
{ ~ H/ZiBL@  
p"j &s  
(!YJ:,!so  
} $aN%[  
aIh} j,  
//线程睡眠 *B9xL[}  
public static void sleep(int nSecond) GK[9IF#_>  
{ nq~fH(QY  
try{ ixE w!t  
Thread.sleep(nSecond); 5u3KL A  
} ?Mn~XN4F_  
catch(Exception e) {dn:1IcN  
{ l}&2A*c.  
e.printStackTrace (); M0OIcMTv  
} k4E9=y?  
} JAT%s %UC  
@AK&R~<  
//日志 @]p {%"$  
public static void log(String sMsg) =K}T; c  
{ PZlPC#E-  
System.err.println(sMsg); bm4Bq>*=U  
} kE|x'(x  
T8Q_JQ  
Hi*|f!,H?  
public static void log(int sMsg) };<?W){!H  
{ gQJLqs"F  
System.err.println(sMsg); bbDm6,  
} iyXd"O  
} &xGpbJG  
:{B']~Xf  
w0vsdM;G  
/* uZ'Z-!=CL  
**TestMethod.java 5(E&jKn&  
*/ 4jZB%tH  
package NetFox; 4^ U%` 1  
F^S]7{  
69apTx  
public class TestMethod { ck3+A/ !z  
fNfa.0 s  
Ajo IL  
public TestMethod() oN%zpz;OR  
{ ///xx/weblogic60b2_win.exe %d%?\jVb  
try{ ?mSZQF:d@  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); *ZFF$0}  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); J9DI(`  
SiteFileFetch fileFetch = new SiteFileFetch(bean); H)EL0 Kv/  
fileFetch.start(); GIn%yB'  
} {2q0Ko<  
catch(Exception e){e.printStackTrace ();} R.F l5B  
 + #E?)  
pU'>!<zGr  
} kqxq'Aq)d  
@^  *62  
X%kJ3{  
public static void main(String[] args) 7YK6e  
{ >]C/ Q6  
new TestMethod(); mg@Ol"2  
} (@qS  
} AE~@F4MK  
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