java中xml格式的字符串保存为xml文件,该怎么解决

String s = "<?xml version=1.0 encoding=UTF-8 ?><root>" +
                    "<version>4</version><device_type>LITE</device_type>" +
                    "<base_config>" +    "<host_name>SAL-200</host_name><datacenter>10.200.0.200</datacenter>" +
                    "<sensors>10.200.0.200</sensors><sensor>10.200.0.200</sensor><sensor>10.200.0.201</sensor>" +
                    "<syslog>" + "<enabled>1</enabled><server>10.200.0.190</server><config_facility>LOG_LOCAL0</config_facility>" +
                    "<config_priority>LOG_INFO</config_priority></syslog><ntp_server><ntp>10.200.0.2</ntp><ntp>10.200.0.3</ntp>" +
                    "</ntp_server>" +    "<admin_host><host><addr>10.180.0.32</addr><comment>test</comment></host><host>" +
                    "<addr>10.180.0.34</addr>" + "<comment>test</comment></host></admin_host><routes><route><dest>default</dest>" +
                    "<gateway>10.180.0.1</gateway>" + "</route><route><dest>10.3.3.0/24</dest><gateway>10.180.0.2</gateway>" +
                    "</route></routes><protocols>" + "<protocol_rdp><idle_timeout>480</idle_timeout>" +
                    "<enable_harddisk>1</enable_harddisk>" + "<enable_sound>1</enable_sound><enable_clipboard>1</enable_clipboard>" +
                    "<disable_copy_server>0</disable_copy_server></protocol_rdp><protocol_ssh>" +
                    "<enable_pubkey_fillin>1</enable_pubkey_fillin><enable_kbd_fillin>1</enable_kbd_fillin></protocol_ssh>" +
                    "<protocol_ftp><record_data>1</record_data></protocol_ftp><protocol_rgs>" +
                    "<enable_clipboard>1</enable_clipboard><disable_copy_server>0</disable_copy_server></protocol_rgs>" +
                    "</protocols></base_config><Policy><netobjects><addr><netobj><name>any</name><addr>0.0.0.0</addr>" +
                    "<mask>0.0.0.0</mask><comment>object for any addr</comment></netobj><netobj><name>server1</name>" +
                    "<addr>10.20.30.40</addr><mask>255.255.255.255</mask><comment>Server of test</comment></netobj>" +
                    "<netobj><name>server2</name><addr>10.20.30.50</addr><mask>255.255.255.255</mask>" +
                    "<comment>Server of test</comment></netobj><netobj><name>server3</name><addr>10.20.30.60</addr>" +
                    "<mask>255.255.255.255</mask><comment>Server of test</comment></netobj></addr><Master>" +
                    "<netobj><name>MA_usera</name><account>usera</account><comment>For master account</comment></netobj></Master>" +
                    "<group><netobj><name>GroupA</name><members><member>server1</member><member>server2</member>" +
                    "<member>server3</member></members><comment>Group of objects</comment></netobj></group></netobjects>" +
                    "<rules><rule><disabled>yes</disabled><src>any</src><dst>server1</dst><protocol>RDP</protocol>" +
                    "<port>3389</port><action>record</action><comment>Server of test</comment></rule><rule>" +
                    "<disabled>no</disabled><src>any</src><dst>server2</dst><protocol>FTP</protocol><port>21</port>" +
                    "<action>record</action><comment>Server of test</comment></rule><rule><disabled>no</disabled>" +
                    "<src>any</src><dst>server3</dst><protocol>SSH</protocol><port>22</port><action>record</action>" +
                    "<comment>Server of test</comment></rule><rule><disabled>no</disabled><src>any</src><dst>server3</dst>" +
                    "<protocol>RGS</protocol><port>22</port><action>record</action><comment>Server of test</comment></rule>" +
                    "</rules></Policy><audit><events><event><id>1</id><serverity>INFO</serverity>" +
                    "<message>Notice, critical command</message></event><event><id>2</id><serverity>WARNING</serverity>" +
                    "<message>Warning, delete all files</message></event><event><id>3</id><serverity>ERROR</serverity>" +
                    "<message>Error, critical file access</message></event></events><keywords><keyword><protocol>ssh</protocol>" +
                    "<direction>send</direction><keyword>iptable</keyword><eventid>1</eventid><log>yes</log><break>no</break>" +
                    "</keyword><keyword><protocol>telnet</protocol><direction>send</direction><keyword>rm -rf</keyword>" +
                    "<eventid>2</eventid><log>yes</log><break>yes</break></keyword><keyword><protocol>ssh</protocol>" +
                    "<direction>send</direction><keyword>passwd</keyword><eventid>3</eventid><log>yes</log><break>yes</break>" +
                    "</keyword></keywords></audit></root>";