http断点续传简单实现（java)

/* P0Aas)!  
**SiteFileFetch.java =$[W,+X6f  
*/ Zq9>VqGe  
package NetFox; 9/^d~ZO  
import java.io.*; we @Yw6<  
import java.net.*; y.%i  
cx<h_  
vDWr|M%``l  
public class SiteFileFetch extends Thread { n/Or~@pHD  
MR[N6E6Mg  
3!1&DII4  
SiteInfoBean siteInfoBean = null; //文件信息Bean xvHOY:  
long[] nStartPos; //开始位置 "_Zh5 g  
long[] nEndPos; //结束位置 mJ/^BT]  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 QK,=5~IJ  
long nFileLength; //文件长度 C?bXrG\  
boolean bFirst = true; //是否第一次取文件 -<_+-t  
boolean bStop = false; //停止标志 5NFq7&rJ6  
File tmpFile; //文件下载的临时信息 '\4c "Ho  
DataOutputStream output; //输出到文件的输出流 n2H&t>N  
t% <pbZO  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 5BZ+b_A>VV  
public SiteFileFetch(SiteInfoBean bean) throws IOException EwC5[bRjUp  
{ }`?7\\6  
siteInfoBean = bean; IwOfZuS
 
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); tP -5  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); % 1OC#&  
if(tmpFile.exists ()) hwc:@'  
{ 1mAUEQ!  
bFirst = false; Al)lWD}j2g  
read_nPos(); 5Gc_LI&v7  
} F%9e@{  
else lrq>TJEcx  
{ (q0No26;(  
nStartPos = new long[bean.getNSplitter()]; 3#7ENV`  
nEndPos = new long[bean.getNSplitter()]; {-~05,zE  
} 1*TXDo_T  
OA\vT${5  
%-T}s`Z  
lK_ ~d_f  
} &9S8al 8"  
oD Q9.t  
Zjw
!In|vC  
public void run() 02;f2;I  
{ {(8U8f<'=y  
//获得文件长度 YWybPD4\(  
//分割文件  >cC Gx  
//实例FileSplitterFetch 721{Ga4~S  
//启动FileSplitterFetch线程 AEiWL.*.  
//等待子线程返回 i/l!Cr2  
try{ Pm;x]Aj  
if(bFirst) -9hp+0 <  
{ oNh68
ON:c  
nFileLength = getFileSize(); 7uWJ6Wk
 
if(nFileLength == -1)  zjZ;xn  
{ W*1d X"S  
System.err.println("File Length is not known!"); #i'C  
} nNkyOaK*4  
else if(nFileLength == -2) :Bdipc  
{ @&/s~3  
System.err.println("File is not access!"); 3U :YA&K(  
} cg>!<T*  
else k8!hvJ)?  
{ UUt~W  
for(int i=0;i<nStartPos.length;i++) ZJiuj!  
{ <L[T'ZE+  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); yBUZVqqDa  
} r@N39O*Wq  
for(int i=0;i<nEndPos.length-1;i++) LG"BfYy6  
{ ,AGM?&A  
nEndPos = nStartPos[i+1]; hpd(d$j  
} Fr938q6^-  
nEndPos[nEndPos.length-1] = nFileLength; Uqb
]e?@  
} u&hDjE  
} S,ouj;B  
F(?Fz8  
[,.[gWA  
//启动子线程 a>-}\GXTA  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; n23%[#,r  
for(int i=0;i<nStartPos.length;i++)
&"@HWF  
{ :HQ8M*o  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +H2m<  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), xMO[3D&D  
nStartPos,nEndPos,i); g] 7{5  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); /y+;g{  
fileSplitterFetch.start(); vWPM:1A  
} pe`TH::p  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Y3 Pz00x  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); :pL1F)-*  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", r_qncy,F  
nEndPos = " + nFileLength); ^=4I|+P,6.  
// fileSplitterFetch[nPos.length-1].start(); (9WL+S  
e _SoM!;  
(1saof*p%  
//等待子线程结束 !;xf>API  
//int count = 0; A1#4nkkc9  
//是否结束while循环 VuJfo9 `E  
boolean breakWhile = false; TsFV ;Sl3  
kx;xO>dC  
B` t6H  
while(!bStop) 8gu'dG=  
{ 02]8|B(E90  
write_nPos(); Fyi?,,  
Utility.sleep(500); PU]7c2.y  
breakWhile = true; 5p#o1I
 
iZDb.9@&t  
: pE-{3I  
for(int i=0;i<nStartPos.length;i++) +Tgy,oD0  
{ i4{ /  
if(!fileSplitterFetch.bDownOver) H`+]dXLB  
{ r-1yJ  
breakWhile = false; B^_$ hJncc  
break; A$H+4L  
} gavQb3EP  
} p3,(*eZ  
if(breakWhile) di)noQXkB-  
break; L:k@BCQM  
7>W+Uq  
9}'l=b:Jms  
//count++; WNF=NNO-R  
//if(count>4) W_e-7=6  
// siteStop(); 'aSZ!R  
} @vQ;>4i.  
wt_?B_n
R  
nkr,  
System.err.println("文件下载结束！"); OW[/%U>
 
} 0
s+rd&  
catch(Exception e){e.printStackTrace ();} 8`rAE_n`%  
} )M|O;~q  
^Xt]wl*]+  
H;b
'"./  
//获得文件长度 P}.yEta  
public long getFileSize() ]6i_d  
{ Wj  
int nFileLength = -1; ^)%wq@Hi  
try{ a-UD_|!  
URL url = new URL(siteInfoBean.getSSiteURL()); (A
y4B*|!  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 7DHT)9lD/  
httpConnection.setRequestProperty("User-Agent","NetFox"); qI4R`P"  
}{w_>!ee  
+i q+  
int responseCode=httpConnection.getResponseCode(); $J;=Ux)$  
if(responseCode>=400) Q%AS;(d  
{ 2jrX  
processErrorCode(responseCode); 9^C!,A{u4  
return -2; //-2 represent access is error ^c[CyZ:a  
} =w;xaxjL  
Rm[rQ}:  
+gD)Yd  
String sHeader; .x-Z+Rs{
g  
q9a wzj  
~;O=
7  
for(int i=1;;i++) Y+PvL|`O  
{ ?SsRN jeL  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); S*DBY~pZy  
//Utility.log(in.readLine()); [<3Q$*Ew  
sHeader=httpConnection.getHeaderFieldKey(i); EiIFVP   
if(sHeader!=null) [&]YVn>kj  
{ {*5;:QnT  
if(sHeader.equals("Content-Length")) 7:R{
~|R  
{ m;tY(kO  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); |]]pHC_/W  
break; At^DY!3vx  
} NGb!7Mu9  
} S#%JSQo
:  
else pFv[z':&Q  
break; MCWG*~f  
} RZ,<D I  
} i5~ /+~  
catch(IOException e){e.printStackTrace ();} &oK/]lub  
catch(Exception e){e.printStackTrace ();} R^Eu}?<f  
+D{*L0$D"  
83 ^,'Z
 
Utility.log(nFileLength); "=Fn.r4I  
U~zN*2-  
Pi]s<3PL  
return nFileLength; WY.\<$7  
} l.NkS  
{/|8g(  
nD?M;XN  
//保存下载信息（文件指针位置） $0`$
)(Y  
private void write_nPos() k~s>8N:&G  
{ <K.C?M(9  
try{ Wp9 2sm+  
output = new DataOutputStream(new FileOutputStream(tmpFile)); @*`UOgP7
 
output.writeInt(nStartPos.length); ]@<3 6ByM  
for(int i=0;i<nStartPos.length;i++) |Nx!g fU  
{ Iz$W3#hi  
// output.writeLong(nPos); J'Mgj$T $  
output.writeLong(fileSplitterFetch.nStartPos); 5)zh@aJ@  
output.writeLong(fileSplitterFetch.nEndPos); IkXKt8`YVA  
} |EEz>ci  
output.close(); S bqM=I+  
} '>Wuu
kC  
catch(IOException e){e.printStackTrace ();} YvP"W/5  
catch(Exception e){e.printStackTrace ();} o!_
; H}pq  
} .Mft+,"  
`\u),$  
m=y,_Pz>U  
//读取保存的下载信息（文件指针位置） z1KC$~{O  
private void read_nPos() $^+K
R]\q  
{ z?) RF[  
try{ v.^ 'x  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); $X\` 7`v  
int nCount = input.readInt(); 63dtO{:4  
nStartPos = new long[nCount]; #?|1~HC  
nEndPos = new long[nCount]; @aPu}Hi  
for(int i=0;i<nStartPos.length;i++) 2Q_{2(nQb  
{ ws(}K+y_  
nStartPos = input.readLong(); !vo'8r?&  
nEndPos = input.readLong(); ][K8\  
} >p#d;wK4_  
input.close(); U@t?jTMBkO  
} VEYKrZA  
catch(IOException e){e.printStackTrace ();} tS/APSY  
catch(Exception e){e.printStackTrace ();} SIBIh-L  
} [,?A
$Z*Z|  
f+88R=-u6S  
K}*p(1$u  
private void processErrorCode(int nErrorCode) k-PRV8WO  
{ T+`GOFx  
System.err.println("Error Code : " + nErrorCode); O}iKPY8K  
} {aa,#B]i  
:x5o3xE  
Pv$"DEXA2  
//停止文件下载 bFdg'_  
public void siteStop()
d~b
H!P  
{ snzH}$Ls  
bStop = true; WMz|FFKVY  
for(int i=0;i<nStartPos.length;i++) Sw9mrhzJfe  
fileSplitterFetch.splitterStop(); G;#t6bk  
IhKas4  
+z?f,`.*  
} &#\7w85$  
} 5}^08Xl  
//负责部分文件的抓取 i2R]lE8  
**FileSplitterFetch.java SE-, 1p  
*/ Kz2^f@5=F  
package NetFox; D'hr\C^  
[&}<!:9'  
;%.k}R%O@  
import java.io.*; 6!PX! UkF  
import java.net.*; bIl0rx[`  
Gg,k  
T`0gtSS  
public class FileSplitterFetch extends Thread { {.8)gVBmA  
-OGy-"  
#UnO~IE.m$  
String sURL; //File URL zSufU2  
long nStartPos; //File Snippet Start Position +A3\Hj&W  
long nEndPos; //File Snippet End Position .8xacVyK2  
int nThreadID; //Thread's ID #Lt+6sa]2@  
boolean bDownOver = false; //Downing is over -hV KPIb  
boolean bStop = false; //Stop identical *ww(5 t  
FileAccessI fileAccessI = null; //File Access interface [#fqyg  
$<DA[ %pv  
FNRE_83  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Q6<Uuiw  
{ >l*9DaZ  
this.sURL = sURL; eeR@p$4i  
this.nStartPos = nStart; >!.lr9(l  
this.nEndPos = nEnd; (zODV4,5k`  
nThreadID = id; |y=F (6Z  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ba:^zO^  
} %SFR.U0}yK  
gM[ J'DMW  
g5N<B+?!i  
public void run() 90k|u'ikOp  
{ FQRcZpv;  
while(nStartPos < nEndPos && !bStop) nk.Eq[08  
{ 
:@'0)7  
tF1%=&ss  
wDY7B  
try{ gxtbu$  
URL url = new URL(sURL); tdK^X1  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); +W[#;)ea(  
httpConnection.setRequestProperty("User-Agent","NetFox"); :u+#:8u  
String sProperty = "bytes="+nStartPos+"-"; <G=@Gl  
httpConnection.setRequestProperty("RANGE",sProperty); 9uoj3Rh<  
Utility.log(sProperty); B>21A9&  
5!fW&OiY  
UoT}m^ G  
InputStream input = httpConnection.getInputStream(); ITPpT  
//logResponseHead(httpConnection); SytDo (_=W  
&Y2P!\\2  
VQ}3r)ch  
byte[] b = new byte[1024]; l:}4 6%  
int nRead; euC,]n.  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ee[NZz  
{ }r<^]Q*&p  
nStartPos += fileAccessI.write(b,0,nRead); [,X,2  
//if(nThreadID == 1) !9OgA  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); dR{ V,H7N  
} 6MQ:C'8T&=  
LZ:\V)5+  
ZO$T/GE6%  
Utility.log("Thread " + nThreadID + " is over!"); 5ml}TSMu'  
bDownOver = true; nOzTHg8  
//nPos = fileAccessI.write (b,0,nRead); |H@p^.;  
} 84cH|j`w  
catch(Exception e){e.printStackTrace ();} 4u7>NQUDu  
} nL~ b   
} ?saVk7Z[|5  
Ka2tr]+s  
SXF_)1QO\W  
//打印回应的头信息 !}48;Pl  
public void logResponseHead(HttpURLConnection con) /a)=B)NH  
{ ay[*b_f  
for(int i=1;;i++) GQWTQIl
]  
{ d'D\#+%>=  
String header=con.getHeaderFieldKey(i); ?"u-@E[m  
if(header!=null) A2S9h,t  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); S*:w\nXP~  
Utility.log(header+" : "+con.getHeaderField(header)); >ON.ftZi  
else &$im^0`r_  
break; Rj=Om  
} DlO;EH  
} (LPD  
S`.-D+.68  
6[7k}9`alz  
public void splitterStop() IQv>{h}  
{ F'*4:WD7  
bStop = true; ,Yz+?SmSZ&  
} =1Jo-!{{  
VHNiTp  
}Cf[nGh|B  
} C>ZeG Vq  
!-~(*tn  
[GM<Wt0  
/* ^q2zqC  
**FileAccess.java ywte\}  
*//文件访问(定位，写) ZeV)/g,w  
package NetFox; P://Zi6>  
import java.io.*; S45_-aE  
,BAF?}04=  
(P8oXb+%  
public class FileAccessI implements Serializable{ &i RX-)^u  
r U5'hK  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 t,nB`g?  
RandomAccessFile oSavedFile; #1R %7*$i  
long nPos; gvYs<,:  

B[50{;X  
2_v>8B  
public FileAccessI() throws IOException
:"]ei@  
{ $S{j}74[  
this("",0); cIjsUqKa  
} A4h/oMis  
g.s oNqt=  
\$"
Xr  
public FileAccessI(String sName,long nPos) throws IOException  CVp<SS(  
{ HbVLL`06*  
oSavedFile = new RandomAccessFile(sName,"rw"); V;(LeuDH|  
this.nPos = nPos; #CmBgxg+M  
oSavedFile.seek(nPos); pT tX[CE  
} o5R40["  
O!tD1^O!1}  
_TF>c:m3  
public synchronized int write(byte[] b,int nStart,int nLen) gZv<_0N  
{ Hc9pWr"N  
int n = -1; SGm?"esEt  
try{ 9_{!nQC.g  
oSavedFile.write(b,nStart,nLen); [DwB7l)O(  
n = nLen; g(k|"g`*  
} #J_i 5KmXJ  
catch(IOException e) ^EOjq  
{ -&}E:zoe  
e.printStackTrace (); OFv} jT  
} 566Qikw2  
lfP|+=^B  
^cm^JyS)  
return n; ri ~2t3gg  
} IIkJ"Qg.  
flqTx)xE  
5@ug1F&  
} wn&2-m*a  
mZyTo/\0  
wQT'~'kL  
/* PQ>JoRs  
**SiteInfoBean.java T^_9R;  
*/ D2bUSRrb  
package NetFox; .&y1gh!=  
jLSZ#H  
0J~4   
public class SiteInfoBean { ~@JC1+  
& j43DYw4  
L%FL{G  
private String sSiteURL; //Site's URL hr5)$qZW  
private String sFilePath; //Saved File's Path 43XuQg4  
private String sFileName; //Saved File's Name wG O)!u 4  
private int nSplitter; //Count of Splited Downloading File 7_,gAE:kG  
.E&~]<  
kns]P<g  
public SiteInfoBean() |+;"^<T)l  
{//nSplitter的缺省值为5 Fm"$W^H  
//default value of nSplitter is 5 8*wI^*Q  
this("","","",5); e+wd>iiB  
} zu#o<6E{  
D3PF(Wx  
il~,y8WTU{  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) jTnu! H2o  
{ /7^~*  
sSiteURL= sURL; H;2pk  
sFilePath = sPath; (&(f`c@I  
sFileName = sName; PW}.`  
this.nSplitter = nSpiltter; Cp%|Q.?  
EeO{G*pq  
0*)79Sz  
} U{EW +>  
4%TC2Laii  
(P?
9Jct  
public String getSSiteURL() T (qu~}  
{ cO:x{~  
return sSiteURL; i(WWF#N5  
} 2xX7dl(cC  
J5k%  
art{PV
4-  
public void setSSiteURL(String value) /03>|Juo  
{ r`2& o  
sSiteURL = value; \ (,2^T'$J  
} F}Au'D&n_  
@lwqkJ  
&+v&Dd&  
public String getSFilePath() +-hmITJv  
{ ?D_zAh?pW  
return sFilePath; DjIs"5Iei  
} x>^S..K}L%  
Y*Pr

 
8/:\iPk0  
public void setSFilePath(String value) Q*I/mUP&f  
{ "q$M\jK#V  
sFilePath = value;  X_lNnk  
} nB.p}k  
$IHa]
9 {  
{#vo^& B  
public String getSFileName() SZ_hGD0  
{ AF@C9s  
return sFileName; _PIk,!<  
} d1-QkW^0y  
b}fH$.V@  
+"!IVHY  
public void setSFileName(String value) DsoF4&>g[B  
{ x-1[2K1"[  
sFileName = value; <x/&Ml+  
} WCH>9Z>cj  
(<h,R@:  
/W9=7&R0  
public int getNSplitter() <XNLeJdY  
{ y.zW>Mfl  
return nSplitter; {}z7N~  
} @bZb#,n]  
PJ'l:IU  
B4kIcHA  
public void setNSplitter(int nCount) +mJAIjH  
{ >_@J&vC  
nSplitter = nCount; FW2} 9#R  
} OHU(?TBo  
} B-RaAiE@  
>(3
y(1;  
;/v^@  
/* .FeEK(  
**Utility.java u%FA.  
*/ PYZ8@G  
package NetFox; kW"N~Xw)  
%:NI@59  
!59q@Mya[  
public class Utility { ZR1EtvVG  
'>Z Ou3>  
Q]8r72uSk  
public Utility() OA_ %%A;o  
{ fIu/*PFPVY  
u7S7lR"lxW  
(j(6%U  
} R7#B_^ $  
n'SnqJ&}  
//线程睡眠 $3So`8Bm[$  
public static void sleep(int nSecond) ^Kn}{m/3Y  
{ u!O)\m-  
try{ +:b|I'S  
Thread.sleep(nSecond); ujaaO6oZ7  
} }q^CR(h (R  
catch(Exception e) |.YL2\  
{ J(0c#}
d  
e.printStackTrace (); (uSfr]89'  
} S;Vj5  
} [ACa<U/  
um/iK}O  
//日志 8"+Kz  
public static void log(String sMsg) L!\I>a5C0G  
{ cG.4%Va@s_  
System.err.println(sMsg); #jQITS7  
} lyP<&<Y5  
RJ`F2b sYN  
-0Ps.B  
public static void log(int sMsg) 0L'h5i>H)  
{ O[!]/qP+.  
System.err.println(sMsg); 4g|}]K1s  
} Fb
F P  
} WHL@]^E@m  
qTG/7tn "  
\j4TDCs_[  
/* e7-U0rrE  
**TestMethod.java OF}vY0oiw?  
*/ z&w@67 >j  
package NetFox; %k9GoX
_  
y:mXv<g  
flRok?iF  
public class TestMethod { Gx!Y 4Q}-  
o<Q~pd#Ip,  
5~v({R.  
public TestMethod() l2i[wc"9  
{ ///xx/weblogic60b2_win.exe P
wf":U)  
try{ L+&$/1h]  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); zpJQ7hym  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 5-*/wKjLz  
SiteFileFetch fileFetch = new SiteFileFetch(bean); q.*k J/L  
fileFetch.start(); _G@)Bj^*  
} [:Sl^ Z&6M  
catch(Exception e){e.printStackTrace ();} -GH>12YP  
:U=*@p4?  
o^mW`g8[  
} #>}cuC@  
t~3!| @3i  
`$05+UU  
public static void main(String[] args) H+` Zp  
{ Pa+%H]vB  
new TestMethod(); {;q zz9 |  
} "d%o%  
} w~Aw?75t  
点击下载更多相关资料