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http断点续传简单实现(java)

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/* /$-Tg)o5i  
**SiteFileFetch.java N"k IQe*}1  
*/ IN!,|)8s  
package NetFox; %pd-{KR  
import java.io.*; @a]O(S>Ub  
import java.net.*; }<=4A\LZ  
,Nk{AiiN  
Z]^Ooy[pb  
public class SiteFileFetch extends Thread { <$+Cd=71\  
Ms61FmA4  
ZvVrbj&  
SiteInfoBean siteInfoBean = null; //文件信息Bean {vf4l4J(  
long[] nStartPos; //开始位置 ^1 U<,<  
long[] nEndPos; //结束位置 OL0W'C9oA  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 *f ;">(`o*  
long nFileLength; //文件长度 L `6 R  
boolean bFirst = true; //是否第一次取文件  Oye:V  
boolean bStop = false; //停止标志 TQ`4dVaf  
File tmpFile; //文件下载的临时信息 ^hyY,X  
DataOutputStream output; //输出到文件的输出流 k. @OFkX.  
I[g;p8jr  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) ,z@"pI b  
public SiteFileFetch(SiteInfoBean bean) throws IOException 3U\| E  
{ z]d2 rzV(_  
siteInfoBean = bean; Nk ~"f5q7  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); MpCK/eiC  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); /&jh10}H  
if(tmpFile.exists ()) ~k[mowz0  
{ 40i]I@:JK  
bFirst = false; 0; PV gO;9  
read_nPos(); vCe]iB  
} [OU[i(,{  
else Z8xKg  
{ -:]-g:;/  
nStartPos = new long[bean.getNSplitter()]; =ICakh!TO  
nEndPos = new long[bean.getNSplitter()]; A@81wv  
} r2.f8U  
+#@)C?G,TF  
QKVFH:"3  
(fUpj^E)p  
} T=~D>2C  
_Yqog/sG  
lXnzomU  
public void run() sngM4ikhs  
{ UZDXv=r|  
//获得文件长度 ]8~{C>ch$  
//分割文件 8x/]H(J  
//实例FileSplitterFetch "> ]{t[Ib  
//启动FileSplitterFetch线程 \.l8]LH  
//等待子线程返回 ?BA~$|lfxu  
try{ c7R<5f  
if(bFirst) ?P>3~3 B  
{ eY'< UO  
nFileLength = getFileSize(); YQ _]Jv k  
if(nFileLength == -1) -+)06BqF}  
{ "MX9h }7  
System.err.println("File Length is not known!"); tA{B~>  
} [!'fE #"a  
else if(nFileLength == -2) 58>C,+  
{ 4apy{W  
System.err.println("File is not access!"); Yn+d!w<3:  
} /t=Fx94  
else 5S/YVRXq  
{ q37d:Hp  
for(int i=0;i<nStartPos.length;i++) |%~Zo:Q<$>  
{ l'm\ *=3  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Z^_-LX:%  
} \:Vm7Zg  
for(int i=0;i<nEndPos.length-1;i++) M4rK  
{ q1_iV.G<  
nEndPos = nStartPos[i+1]; U5!~ @XjG>  
} P+2@,?9#  
nEndPos[nEndPos.length-1] = nFileLength; p?idl`?^3  
} ih\=mB  
} P7D__hoE  
c80!Ub@  
,B8u?{O  
//启动子线程 s+ a} _a:  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 8{)j"rghah  
for(int i=0;i<nStartPos.length;i++) l1#F1q`^t  
{ _i@4R<  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), X :wfmb  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ~[ZRE @  
nStartPos,nEndPos,i); E9 6` aF{]  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); `SM37({c  
fileSplitterFetch.start(); *w,C5 f  
} =4_Er{AT  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), `~;`q  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 0CR~ vQf#r  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", C>~ms2c  
nEndPos = " + nFileLength); zNRR('B?  
// fileSplitterFetch[nPos.length-1].start(); HpGI\s  
QFX/x  
(Rs052m1  
//等待子线程结束 [#mRlL0yk  
//int count = 0; (JI[y"2  
//是否结束while循环 <yg! D21Y  
boolean breakWhile = false; B$D7}=|kc  
n~Qo@%Jr  
UY~N4IR8  
while(!bStop) ms/!8X$Mz  
{ al@Hr*'  
write_nPos(); +DwE~l  
Utility.sleep(500); OGWZq(c"6  
breakWhile = true; 6i7+.#s  
JZ>E<U9&  
,C;%AS/  
for(int i=0;i<nStartPos.length;i++) W<tw],M-#  
{ u?%FD~l:uU  
if(!fileSplitterFetch.bDownOver) /+JHnedK  
{ ,We'A R3X  
breakWhile = false; -.t/c}a#  
break; ^=@`U_(,G  
} \.K4tY+V  
} j[Z<|Da  
if(breakWhile) [$e\?c  
break; `:#IZ  
lNbAt4]}f(  
Rn9e#_Az  
//count++; H7?Sd(U  
//if(count>4) z;Yo76P  
// siteStop(); d]r?mnN W  
} 155vY  
C.N#y`g  
LCMZw6p  
System.err.println("文件下载结束!"); @|6#]&v`  
} $az9Fmta  
catch(Exception e){e.printStackTrace ();} G:4'')T  
} @wPyXl  
w:HRzU>  
\ Dccf_(Pb  
//获得文件长度 3](At%ss  
public long getFileSize() aNDpCpy  
{ )l6(ss!J  
int nFileLength = -1; W'! I+nh  
try{ tYUg%2G  
URL url = new URL(siteInfoBean.getSSiteURL()); Q$58 K9  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); m bZn[D_zi  
httpConnection.setRequestProperty("User-Agent","NetFox"); (U([T-H  
Lc! t  
o>75s#= b=  
int responseCode=httpConnection.getResponseCode(); Y{7)$'At  
if(responseCode>=400) mPJ@hr%3  
{ s0\}Q=s[  
processErrorCode(responseCode); !$pnE:K  
return -2; //-2 represent access is error 32z2c:G  
} *6/OLAkyF  
x%`tWE|  
WbJ  
String sHeader; JJ4w]Dd4  
7!PU}[:  
+. tcEbFL  
for(int i=1;;i++) 5a%i%+;N  
{ ]QSQr *  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 2ut)m\)/)  
//Utility.log(in.readLine()); r<OqI*7  
sHeader=httpConnection.getHeaderFieldKey(i); p>h}k_s  
if(sHeader!=null) W4&Itj  
{ I' 'X\/|  
if(sHeader.equals("Content-Length")) 7Sl"q=>  
{ {xu~Dx  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); o7kQ&w   
break; oCSJ<+[(C  
} &6&$vF65c  
}  N~vK8j@  
else PM^Xh*~  
break; Ti>2N  
} PX >>h}%  
} ~9Cw5rwH<;  
catch(IOException e){e.printStackTrace ();} -7u_\XFk  
catch(Exception e){e.printStackTrace ();} yW@YW_2;4  
@ S)p{T5G  
#3}!Q0   
Utility.log(nFileLength); hka`STK{  
0w!:YB,}  
9S/X,|i  
return nFileLength; OLE@35"v]  
} ;T3}#Q*qC  
r1a/'+   
6QePrf  
//保存下载信息(文件指针位置) FV\$M6 _  
private void write_nPos() q'KXn0IY#  
{ lS |:4U.  
try{ @m+FAdA 0  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 0,1)Sg*  
output.writeInt(nStartPos.length); UL0n>Wa5  
for(int i=0;i<nStartPos.length;i++) iJSyi;l|  
{ >uR;^B5m  
// output.writeLong(nPos); eCwR }m?_  
output.writeLong(fileSplitterFetch.nStartPos); p+}eP|N  
output.writeLong(fileSplitterFetch.nEndPos); d6ckvD[  
} iJb-F*_y  
output.close(); >2ny/AK|  
} ZN}U^9m=  
catch(IOException e){e.printStackTrace ();} bo[[<j!"I  
catch(Exception e){e.printStackTrace ();} `teaE7^Wm  
} %ZT I ?a  
Lm7fz9F%  
~}g) N  
//读取保存的下载信息(文件指针位置) @<z#a9  
private void read_nPos() \4Z"s[8}  
{ EfqC_,J*3  
try{ 4\y>pXML-U  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); &uXu$)IZ  
int nCount = input.readInt(); N4w&g-  
nStartPos = new long[nCount]; UQO?hZ!y/.  
nEndPos = new long[nCount]; +?^lnoX  
for(int i=0;i<nStartPos.length;i++) 5!qLJmd=  
{ CO{AC~  
nStartPos = input.readLong(); bYwe/sR  
nEndPos = input.readLong(); _Kg"l5?B  
} no9=K4h`  
input.close(); qb KcI+)47  
} YJ{_%z|U  
catch(IOException e){e.printStackTrace ();} ESi-'R&  
catch(Exception e){e.printStackTrace ();} mhMRY9ahB  
} zv~b-Tp  
xPMX\aI|l  
@] 3`S  
private void processErrorCode(int nErrorCode) FB n . 4  
{ Am=O-; b'8  
System.err.println("Error Code : " + nErrorCode); eb7~\|9l1i  
} Hr/Q?7g  
e!P]$em|1E  
\4n9m  
//停止文件下载 /JmWiBQIn  
public void siteStop() 0RP{_1k  
{ =' &TqiIv"  
bStop = true;  EHda  
for(int i=0;i<nStartPos.length;i++) |3=tF"h  
fileSplitterFetch.splitterStop(); tx]!|x" F  
YQaL)t$0  
%kL]-Z  
} 9` G}GU]@}  
} !uN_<!  
//负责部分文件的抓取 T^H`$;\  
**FileSplitterFetch.java *wV`7\@  
*/ L87=*_!B;  
package NetFox; I ka V g L  
>:P-3#e*  
6B@{X^6y  
import java.io.*; M3YC@(N% k  
import java.net.*; 8g6G},Y0  
pF7S("#R  
E[tEW0ub  
public class FileSplitterFetch extends Thread { J" U!j  
o_?A^u  
-bp7X{&  
String sURL; //File URL 2$1D+(5;  
long nStartPos; //File Snippet Start Position 0]2@T=*kTY  
long nEndPos; //File Snippet End Position l%v2O'h  
int nThreadID; //Thread's ID vR'rYDtU@  
boolean bDownOver = false; //Downing is over 0ae}!LO  
boolean bStop = false; //Stop identical ZCDcf   
FileAccessI fileAccessI = null; //File Access interface e`;U9Z  
$ -M'  
5<Y-?23  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Mf`@X[-;  
{ -_fh=}.n+"  
this.sURL = sURL; v}&J*}_XZ  
this.nStartPos = nStart; PZhpp"  
this.nEndPos = nEnd; bf$4Z: Y  
nThreadID = id; <26Jif:  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 q[TW  
} ef]60OtP  
.h\[7r  
k[/`G5  
public void run() v:u=.by99  
{ V,>uM >$  
while(nStartPos < nEndPos && !bStop) ,{g B$8z^  
{ )k&!&  
B/b S:  
G$CI~0Se:  
try{ 7hl,dtn7  
URL url = new URL(sURL); ' O d_:]  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); we2D!Ywr  
httpConnection.setRequestProperty("User-Agent","NetFox"); 9pq-"?vHY0  
String sProperty = "bytes="+nStartPos+"-"; TbR!u:J  
httpConnection.setRequestProperty("RANGE",sProperty);  ui1h M  
Utility.log(sProperty); R% )7z)~  
R2dCp|6A  
a'YK1QX  
InputStream input = httpConnection.getInputStream(); |v= */e  
//logResponseHead(httpConnection); |H4f&& Wd  
Uf<IXx&;  
<jtu/U]78|  
byte[] b = new byte[1024]; Rx.dM_S  
int nRead; |gM@}!DL  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) P{o/ /M  
{ I] 0 D*z  
nStartPos += fileAccessI.write(b,0,nRead); K5:>  
//if(nThreadID == 1) z#t;n  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); IGcYPL\&  
} fz`\-"f]  
LABLT;c  
h|XLL|:  
Utility.log("Thread " + nThreadID + " is over!"); (-esUOB.  
bDownOver = true; 8B|B[,`  
//nPos = fileAccessI.write (b,0,nRead); [:bYd}J  
} mE3M$2}  
catch(Exception e){e.printStackTrace ();} ec"+Il  
} p|VgtQ/ )%  
} 4'U #<8  
p$zj2W+sN  
S'%!KGVe  
//打印回应的头信息 R^tDL  
public void logResponseHead(HttpURLConnection con) VT5o#NR{R  
{ TW~9<c  
for(int i=1;;i++) D|X@aUp 8}  
{ (xlA S  
String header=con.getHeaderFieldKey(i); F!~oJ  
if(header!=null) ljw>[wNv  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); GB` G(a  
Utility.log(header+" : "+con.getHeaderField(header)); av4g/7=  
else ip2BvN&  
break; |-.r9;-b  
} E:S (v  
} kc}&\y  
g;t>jgX  
G| .5.FK^  
public void splitterStop() Yp8GW1@  
{ 0Nq6>^ %  
bStop = true; H<bB@(i  
} D?}K|z LQ  
EmubpUS;  
br_D Orq|  
} G5'HrV  
yfCdK-9+B  
<jHo2U8/"s  
/* ~91) DNaE  
**FileAccess.java 6 xAR:  
*//文件访问(定位,写) V~_aM@q1  
package NetFox; Tq`rc"&7u  
import java.io.*; !%Qm{R  
iK <vr  
M_EXA _  
public class FileAccessI implements Serializable{ g=_@j`  
>Mc,c(CvU  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Pq)C(Z  
RandomAccessFile oSavedFile; MPF;P&6  
long nPos; =r1 @?x  
1"P^!N  
L[cl$ pYV  
public FileAccessI() throws IOException pG(%yIiAi  
{ Hv.n O-c  
this("",0); ecG,[1];  
} 3F|#nq  
b$G &i'd  
kPg| o3H  
public FileAccessI(String sName,long nPos) throws IOException s'^"s_j  
{ Y76UhtYH  
oSavedFile = new RandomAccessFile(sName,"rw"); NY9\a[[^[8  
this.nPos = nPos; Gtpl5gQH  
oSavedFile.seek(nPos); xcA5  
} xix: = a  
]Y@B= 5e/  
v35=4>Y  
public synchronized int write(byte[] b,int nStart,int nLen) Ht!]%  
{ S1oP_A[|  
int n = -1; Qfd4")zhG  
try{ [ #1<W`95  
oSavedFile.write(b,nStart,nLen); uf<nVdC.  
n = nLen; N)b.$aC  
} yJG M"$  
catch(IOException e) l=?G"1  
{ C AvyS  
e.printStackTrace (); BA t0YE`-,  
} 1# -=|:U  
%`1 p8>n  
tsvh/)V  
return n; Uel^rfE`  
} w5tcO%+k1  
qKL mL2O  
N 56/\1R  
} qL?`l;+  
|H7f@b]Sk  
uDXRw*rTv  
/* eJ O+MurO  
**SiteInfoBean.java ^CWxYDG*  
*/ XlGDv*d:#d  
package NetFox; K:\db'``  
(np60mX<  
9j~|m  
public class SiteInfoBean { eQQ*ZNG  
!HPye@Ua  
n~|sMpd,M1  
private String sSiteURL; //Site's URL a-<&(jV  
private String sFilePath; //Saved File's Path /6PL  
private String sFileName; //Saved File's Name :]g>8sWL  
private int nSplitter; //Count of Splited Downloading File Bp>Z?"hTe  
(viGL|Ogn  
bw& U[|A0%  
public SiteInfoBean() @K:TGo,%I  
{//nSplitter的缺省值为5 sj& j\<(  
//default value of nSplitter is 5 C`LHFqv  
this("","","",5); lZ![?t}2`  
} c.;}e:)s  
zEYT,l  
mxQPOu  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) >^5U XQr  
{ r[ }5<S Q  
sSiteURL= sURL; ,8^QV3  
sFilePath = sPath; y m~  
sFileName = sName; f7_EqS=(  
this.nSplitter = nSpiltter; <+\ w.!  
M!j: 2dT"  
_cw~N p  
} # 2qDn^s  
oYn|>`+6:y  
ZIo%(IT!c  
public String getSSiteURL() ?1kXV n$  
{ xYUC|c1Q9  
return sSiteURL; XzF-g*e  
} k9Xv@v  
F&= X/  
 wq@{85  
public void setSSiteURL(String value) _)U[c;^6  
{ U&}v1wdZ3  
sSiteURL = value; VQ,;~^Td  
} )J<VDO:_YA  
V+'C71-P  
DN%b!K:  
public String getSFilePath() (o5^@aDr  
{ V0ig#?]  
return sFilePath; S7Tc9"oqV  
} @P@j9yR  
]W9{<+&  
0 P]+/  
public void setSFilePath(String value) >q !:*  
{ ZP}NFh%,u  
sFilePath = value; b|KlWt'  
} f0 d*%  
}mx>3G{d  
p|f5w"QcH  
public String getSFileName() z +NwGVk3  
{ jf WZLb)  
return sFileName; ;[,r./XmH  
} f+xhS,iDR  
4[o/p8*/  
cU  
public void setSFileName(String value) kl0|22"Gz  
{ 6myF!  H=  
sFileName = value; (n+FEE<  
} @3_[NI%  
ys~oJb~  
CqkY_z  
public int getNSplitter() @7j$$  
{ s=BJ7iU_68  
return nSplitter; Y :-O/X  
} Q%Fa1h:2&  
bnYd19>  
RP1sQ6$  
public void setNSplitter(int nCount) [42EqVR  
{ $YztLcn   
nSplitter = nCount; r-aCa/4y!  
} "k'P #v{f  
} lc8zF5  
8EBy5X}US  
dtDT^~  
/* zHu w[  
**Utility.java \zMx~-2oN  
*/ 5dXDL~/2p  
package NetFox; j : $Ruy  
4!k 0  
.s8u?1b  
public class Utility { &o]ic(74c?  
&s>E~M0+J  
j+6`nN7L  
public Utility() pHKGK7 S-  
{ (S)jV 0  
&RL j^A!  
NB=!1;^J  
} 6 #m:=  
^2 }p%j >  
//线程睡眠 qvN`46c  
public static void sleep(int nSecond)  aWTvowA  
{ Hph$Z 1{  
try{ k0^t$J W  
Thread.sleep(nSecond); )r|Pm-:A{  
} cf{rK`Ff^  
catch(Exception e) IQNvhl.{  
{ @||GMA+|  
e.printStackTrace (); UJ^MS4;I3  
} 8^2E77s4U  
} dZIruZ)x  
V|`w/P9g4  
//日志 g3Z"ri~!G  
public static void log(String sMsg) eX3|<Bf  
{ 3@8Zy:[8<  
System.err.println(sMsg); kl[Jt)"4@  
} <#%kmYSL  
4E 0 Y=  
l37) Q  
public static void log(int sMsg) 5kdh!qy[$,  
{ qw35LyL  
System.err.println(sMsg); tuIQiWHbM  
} <#>{7" }  
} %Xjg/5G-  
+txHj(Y`  
Q35jJQ$<`  
/* h'|J$   
**TestMethod.java ^w6~?'}  
*/ GEbm$\  
package NetFox; m&{%6  
A=bBI>GEYP  
{O"N2W  
public class TestMethod { =Eb4Iyz  
& T&>4I!'M  
g), t  
public TestMethod() O&@pi-=o  
{ ///xx/weblogic60b2_win.exe ay`A Gr  
try{ .0b4"0~T6  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ? e<D +  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); rcU*6`IWA  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ''3b[<  
fileFetch.start(); dk[MT'DV  
} /&!4oBna  
catch(Exception e){e.printStackTrace ();} "R % 3v.Z  
o%_Hmd;_'  
dSPye z  
} Uf\,U8UB  
\@F~4,VT  
|Q*OA  
public static void main(String[] args) HBiUp$(mB  
{ nz_1Fu>g|  
new TestMethod(); >(BAIjF E\  
} :/~TV   
} (!"&c* <  
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