[置顶] MyCat

数据库路由中间件MyCat - 源代码篇（12） 4.配置模块 4.2 schema.xml 接上一篇，接下来载入每个schema的配置（也就是每个MyCat中虚拟化的数据库的配置）： XMLSchemaLoader.java private void loadSchemas(Element root) { NodeList list = root . getElemen

数据库路由中间件MyCat - 源代码篇（12）

4.配置模块

4.2 schema.xml

接上一篇，接下来载入每个schema的配置（也就是每个MyCat中虚拟化的数据库的配置）：
XMLSchemaLoader.java

<code class=" hljs lasso"><span class="hljs-keyword">private</span> <span class="hljs-literal">void</span> loadSchemas(Element root) {
        NodeList <span class="hljs-built_in">list</span> <span class="hljs-subst">=</span> root<span class="hljs-built_in">.</span>getElementsByTagName(<span class="hljs-string">"schema"</span>);
    for (int i <span class="hljs-subst">=</span> <span class="hljs-number">0</span>, n <span class="hljs-subst">=</span> <span class="hljs-built_in">list</span><span class="hljs-built_in">.</span>getLength(); i <span class="hljs-subst"><</span> n; i<span class="hljs-subst">++</span>) {
        Element schemaElement <span class="hljs-subst">=</span> (Element) <span class="hljs-built_in">list</span><span class="hljs-built_in">.</span>item(i);
        <span class="hljs-comment">//读取各个属性</span>
        <span class="hljs-built_in">String</span> name <span class="hljs-subst">=</span> schemaElement<span class="hljs-built_in">.</span>getAttribute(<span class="hljs-string">"name"</span>);
        <span class="hljs-built_in">String</span> dataNode <span class="hljs-subst">=</span> schemaElement<span class="hljs-built_in">.</span>getAttribute(<span class="hljs-string">"dataNode"</span>);
        <span class="hljs-built_in">String</span> checkSQLSchemaStr <span class="hljs-subst">=</span> schemaElement<span class="hljs-built_in">.</span>getAttribute(<span class="hljs-string">"checkSQLschema"</span>);
        <span class="hljs-built_in">String</span> sqlMaxLimitStr <span class="hljs-subst">=</span> schemaElement<span class="hljs-built_in">.</span>getAttribute(<span class="hljs-string">"sqlMaxLimit"</span>);
        int sqlMaxLimit <span class="hljs-subst">=</span> <span class="hljs-subst">-</span><span class="hljs-number">1</span>;
        <span class="hljs-comment">//读取sql返回结果集限制</span>
        <span class="hljs-keyword">if</span> (sqlMaxLimitStr <span class="hljs-subst">!=</span> <span class="hljs-built_in">null</span> <span class="hljs-subst">&&</span> <span class="hljs-subst">!</span>sqlMaxLimitStr<span class="hljs-built_in">.</span>isEmpty()) {
            sqlMaxLimit <span class="hljs-subst">=</span> <span class="hljs-built_in">Integer</span><span class="hljs-built_in">.</span>valueOf(sqlMaxLimitStr);
        }

        <span class="hljs-comment">// check dataNode already exists or not,看schema标签中是否有datanode</span>
        <span class="hljs-built_in">String</span> defaultDbType <span class="hljs-subst">=</span> <span class="hljs-built_in">null</span>;
        <span class="hljs-comment">//校验检查并添加dataNode</span>
        <span class="hljs-keyword">if</span> (dataNode <span class="hljs-subst">!=</span> <span class="hljs-built_in">null</span> <span class="hljs-subst">&&</span> <span class="hljs-subst">!</span>dataNode<span class="hljs-built_in">.</span>isEmpty()) {
            <span class="hljs-built_in">List</span><span class="hljs-subst"><</span><span class="hljs-built_in">String</span><span class="hljs-subst">></span> dataNodeLst <span class="hljs-subst">=</span> <span class="hljs-literal">new</span> ArrayList<span class="hljs-subst"><</span><span class="hljs-built_in">String</span><span class="hljs-subst">></span>(<span class="hljs-number">1</span>);
            dataNodeLst<span class="hljs-built_in">.</span>add(dataNode);
            checkDataNodeExists(dataNodeLst);
            <span class="hljs-built_in">String</span> dataHost <span class="hljs-subst">=</span> dataNodes<span class="hljs-built_in">.</span>get(dataNode)<span class="hljs-built_in">.</span>getDataHost();
            defaultDbType <span class="hljs-subst">=</span> dataHosts<span class="hljs-built_in">.</span>get(dataHost)<span class="hljs-built_in">.</span>getDbType();
        } <span class="hljs-keyword">else</span> {
            dataNode <span class="hljs-subst">=</span> <span class="hljs-built_in">null</span>;
        }
        <span class="hljs-comment">//加载schema下所有tables</span>
        <span class="hljs-built_in">Map</span><span class="hljs-subst"><</span><span class="hljs-built_in">String</span>, TableConfig<span class="hljs-subst">></span> tables <span class="hljs-subst">=</span> loadTables(schemaElement);
        <span class="hljs-comment">//判断schema是否重复</span>
        <span class="hljs-keyword">if</span> (schemas<span class="hljs-built_in">.</span>containsKey(name)) {
            throw <span class="hljs-literal">new</span> ConfigException(<span class="hljs-string">"schema "</span> <span class="hljs-subst">+</span> name <span class="hljs-subst">+</span> <span class="hljs-string">" duplicated!"</span>);
        }

        <span class="hljs-comment">// 设置了table的不需要设置dataNode属性，没有设置table的必须设置dataNode属性</span>
        <span class="hljs-keyword">if</span> (dataNode <span class="hljs-subst">==</span> <span class="hljs-built_in">null</span> <span class="hljs-subst">&&</span> tables<span class="hljs-built_in">.</span>size() <span class="hljs-subst">==</span> <span class="hljs-number">0</span>) {
            throw <span class="hljs-literal">new</span> ConfigException(
                    <span class="hljs-string">"schema "</span> <span class="hljs-subst">+</span> name <span class="hljs-subst">+</span> <span class="hljs-string">" didn't config tables,so you must set dataNode property!"</span>);
        }

        SchemaConfig schemaConfig <span class="hljs-subst">=</span> <span class="hljs-literal">new</span> SchemaConfig(name, dataNode,
                tables, sqlMaxLimit, <span class="hljs-string">"true"</span><span class="hljs-built_in">.</span>equalsIgnoreCase(checkSQLSchemaStr));

        <span class="hljs-comment">//设定DB类型，这对之后的sql语句路由解析有帮助</span>
        <span class="hljs-keyword">if</span> (defaultDbType <span class="hljs-subst">!=</span> <span class="hljs-built_in">null</span>) {
            schemaConfig<span class="hljs-built_in">.</span>setDefaultDataNodeDbType(defaultDbType);
            <span class="hljs-keyword">if</span> (<span class="hljs-subst">!</span><span class="hljs-string">"mysql"</span><span class="hljs-built_in">.</span>equalsIgnoreCase(defaultDbType)) {
                schemaConfig<span class="hljs-built_in">.</span>setNeedSupportMultiDBType(<span class="hljs-literal">true</span>);
            }
        }

        <span class="hljs-comment">// 判断是否有不是mysql的数据库类型，方便解析判断是否启用多数据库分页语法解析</span>
        for (<span class="hljs-built_in">String</span> tableName : tables<span class="hljs-built_in">.</span>keySet()) {
            TableConfig tableConfig <span class="hljs-subst">=</span> tables<span class="hljs-built_in">.</span>get(tableName);
            <span class="hljs-keyword">if</span> (isHasMultiDbType(tableConfig)) {
                schemaConfig<span class="hljs-built_in">.</span>setNeedSupportMultiDBType(<span class="hljs-literal">true</span>);
                break;
            }
        }
        <span class="hljs-comment">//记录每种dataNode的DB类型</span>
        <span class="hljs-built_in">Map</span><span class="hljs-subst"><</span><span class="hljs-built_in">String</span>, <span class="hljs-built_in">String</span><span class="hljs-subst">></span> dataNodeDbTypeMap <span class="hljs-subst">=</span> <span class="hljs-literal">new</span> HashMap<span class="hljs-subst"><></span>();
        for (<span class="hljs-built_in">String</span> dataNodeName : dataNodes<span class="hljs-built_in">.</span>keySet()) {
            DataNodeConfig dataNodeConfig <span class="hljs-subst">=</span> dataNodes<span class="hljs-built_in">.</span>get(dataNodeName);
            <span class="hljs-built_in">String</span> dataHost <span class="hljs-subst">=</span> dataNodeConfig<span class="hljs-built_in">.</span>getDataHost();
            DataHostConfig dataHostConfig <span class="hljs-subst">=</span> dataHosts<span class="hljs-built_in">.</span>get(dataHost);
            <span class="hljs-keyword">if</span> (dataHostConfig <span class="hljs-subst">!=</span> <span class="hljs-built_in">null</span>) {
                <span class="hljs-built_in">String</span> dbType <span class="hljs-subst">=</span> dataHostConfig<span class="hljs-built_in">.</span>getDbType();
                dataNodeDbTypeMap<span class="hljs-built_in">.</span>put(dataNodeName, dbType);
            }
        }
        schemaConfig<span class="hljs-built_in">.</span>setDataNodeDbTypeMap(dataNodeDbTypeMap);
        schemas<span class="hljs-built_in">.</span>put(name, schemaConfig);
    }
}</code>

首先读取schema每个配置属性项，并作有效性判断。比如默认的dataNode是否存在。只要验证之前读取的dataNode里面有没有就可以

<code class=" hljs cs"><span class="hljs-keyword">private</span> <span class="hljs-keyword">void</span> <span class="hljs-title">checkDataNodeExists</span>(Collection<String> nodes) {
    <span class="hljs-keyword">if</span> (nodes == <span class="hljs-keyword">null</span> || nodes.size() < <span class="hljs-number">1</span>) {
        <span class="hljs-keyword">return</span>;
    }
    <span class="hljs-keyword">for</span> (String node : nodes) {
        <span class="hljs-keyword">if</span> (!dataNodes.containsKey(node)) {
            <span class="hljs-keyword">throw</span> <span class="hljs-keyword">new</span> ConfigException(<span class="hljs-string">"dataNode '"</span> + node + <span class="hljs-string">"' is not found!"</span>);
        }
    }
}</code>

之后载入所有的table和childTable：

<code class=" hljs javascript">private Map<<span class="hljs-built_in">String</span>, TableConfig> loadTables(Element node) {

    <span class="hljs-comment">// Map<String, TableConfig> tables = new HashMap<String, TableConfig>();</span>

    <span class="hljs-comment">// 支持表名中包含引号[`] BEN GONG</span>
    Map<<span class="hljs-built_in">String</span>, TableConfig> tables = <span class="hljs-keyword">new</span> TableConfigMap();
    NodeList nodeList = node.getElementsByTagName(<span class="hljs-string">"table"</span>);
    <span class="hljs-keyword">for</span> (int i = <span class="hljs-number">0</span>; i < nodeList.getLength(); i++) {
        Element tableElement = (Element) nodeList.item(i);
        <span class="hljs-built_in">String</span> tableNameElement = tableElement.getAttribute(<span class="hljs-string">"name"</span>).toUpperCase();

        <span class="hljs-comment">//TODO:路由, 增加对动态日期表的支持</span>
        <span class="hljs-built_in">String</span> tableNameSuffixElement = tableElement.getAttribute(<span class="hljs-string">"nameSuffix"</span>).toUpperCase();
        <span class="hljs-keyword">if</span> ( !<span class="hljs-string">""</span>.equals( tableNameSuffixElement ) ) {               

            <span class="hljs-keyword">if</span>( tableNameElement.split(<span class="hljs-string">","</span>).length > <span class="hljs-number">1</span> ) {
                <span class="hljs-keyword">throw</span> <span class="hljs-keyword">new</span> ConfigException(<span class="hljs-string">"nameSuffix "</span> + tableNameSuffixElement + <span class="hljs-string">", require name parameter cannot multiple breaks!"</span>);
            }
            <span class="hljs-comment">//前缀用来标明日期格式</span>
            tableNameElement = doTableNameSuffix(tableNameElement, tableNameSuffixElement);
        }
        <span class="hljs-comment">//记录主键，用于之后路由分析，以及启用自增长主键</span>
        <span class="hljs-built_in">String</span>[] tableNames = tableNameElement.split(<span class="hljs-string">","</span>);
        <span class="hljs-built_in">String</span> primaryKey = tableElement.hasAttribute(<span class="hljs-string">"primaryKey"</span>) ? tableElement.getAttribute(<span class="hljs-string">"primaryKey"</span>).toUpperCase() : <span class="hljs-literal">null</span>;
        <span class="hljs-comment">//记录是否主键自增，默认不是，（启用全局sequence handler）</span>
        boolean autoIncrement = <span class="hljs-literal">false</span>;
        <span class="hljs-keyword">if</span> (tableElement.hasAttribute(<span class="hljs-string">"autoIncrement"</span>)) {
            autoIncrement = <span class="hljs-built_in">Boolean</span>.parseBoolean(tableElement.getAttribute(<span class="hljs-string">"autoIncrement"</span>));
        }
        <span class="hljs-comment">//记录是否需要加返回结果集限制，默认需要加</span>
        boolean needAddLimit = <span class="hljs-literal">true</span>;
        <span class="hljs-keyword">if</span> (tableElement.hasAttribute(<span class="hljs-string">"needAddLimit"</span>)) {
            needAddLimit = <span class="hljs-built_in">Boolean</span>.parseBoolean(tableElement.getAttribute(<span class="hljs-string">"needAddLimit"</span>));
        }
        <span class="hljs-comment">//记录type，是否为global</span>
        <span class="hljs-built_in">String</span> tableTypeStr = tableElement.hasAttribute(<span class="hljs-string">"type"</span>) ? tableElement.getAttribute(<span class="hljs-string">"type"</span>) : <span class="hljs-literal">null</span>;
        int tableType = TableConfig.TYPE_GLOBAL_DEFAULT;
        <span class="hljs-keyword">if</span> (<span class="hljs-string">"global"</span>.equalsIgnoreCase(tableTypeStr)) {
            tableType = TableConfig.TYPE_GLOBAL_TABLE;
        }
        <span class="hljs-comment">//记录dataNode，就是分布在哪些dataNode上</span>
        <span class="hljs-built_in">String</span> dataNode = tableElement.getAttribute(<span class="hljs-string">"dataNode"</span>);
        TableRuleConfig tableRule = <span class="hljs-literal">null</span>;
        <span class="hljs-keyword">if</span> (tableElement.hasAttribute(<span class="hljs-string">"rule"</span>)) {
            <span class="hljs-built_in">String</span> ruleName = tableElement.getAttribute(<span class="hljs-string">"rule"</span>);
            tableRule = tableRules.get(ruleName);
            <span class="hljs-keyword">if</span> (tableRule == <span class="hljs-literal">null</span>) {
                <span class="hljs-keyword">throw</span> <span class="hljs-keyword">new</span> ConfigException(<span class="hljs-string">"rule "</span> + ruleName + <span class="hljs-string">" is not found!"</span>);
            }
        }

        boolean ruleRequired = <span class="hljs-literal">false</span>;
        <span class="hljs-comment">//记录是否绑定有分片规则</span>
        <span class="hljs-keyword">if</span> (tableElement.hasAttribute(<span class="hljs-string">"ruleRequired"</span>)) {
            ruleRequired = <span class="hljs-built_in">Boolean</span>.parseBoolean(tableElement.getAttribute(<span class="hljs-string">"ruleRequired"</span>));
        }

        <span class="hljs-keyword">if</span> (tableNames == <span class="hljs-literal">null</span>) {
            <span class="hljs-keyword">throw</span> <span class="hljs-keyword">new</span> ConfigException(<span class="hljs-string">"table name is not found!"</span>);
        }
        <span class="hljs-comment">//distribute函数，重新编排dataNode</span>
        <span class="hljs-built_in">String</span> distPrex = <span class="hljs-string">"distribute("</span>;
        boolean distTableDns = dataNode.startsWith(distPrex);
        <span class="hljs-keyword">if</span> (distTableDns) {
            dataNode = dataNode.substring(distPrex.length(), dataNode.length() - <span class="hljs-number">1</span>);
        }
        <span class="hljs-comment">//分表功能</span>
        <span class="hljs-built_in">String</span> subTables = tableElement.getAttribute(<span class="hljs-string">"subTables"</span>);

        <span class="hljs-keyword">for</span> (int j = <span class="hljs-number">0</span>; j < tableNames.length; j++) {
            <span class="hljs-built_in">String</span> tableName = tableNames[j];
            TableConfig table = <span class="hljs-keyword">new</span> TableConfig(tableName, primaryKey,
                    autoIncrement, needAddLimit, tableType, dataNode,
                    getDbType(dataNode),
                    (tableRule != <span class="hljs-literal">null</span>) ? tableRule.getRule() : <span class="hljs-literal">null</span>,
                    ruleRequired, <span class="hljs-literal">null</span>, <span class="hljs-literal">false</span>, <span class="hljs-literal">null</span>, <span class="hljs-literal">null</span>,subTables);

            checkDataNodeExists(table.getDataNodes());

            <span class="hljs-keyword">if</span> (distTableDns) {
                distributeDataNodes(table.getDataNodes());
            }
            <span class="hljs-comment">//检查去重</span>
            <span class="hljs-keyword">if</span> (tables.containsKey(table.getName())) {
                <span class="hljs-keyword">throw</span> <span class="hljs-keyword">new</span> ConfigException(<span class="hljs-string">"table "</span> + tableName + <span class="hljs-string">" duplicated!"</span>);
            }
            <span class="hljs-comment">//放入map</span>
            tables.put(table.getName(), table);
        }
        <span class="hljs-comment">//只有tableName配置的是单个表（没有逗号）的时候才能有子表</span>
        <span class="hljs-keyword">if</span> (tableNames.length == <span class="hljs-number">1</span>) {
            TableConfig table = tables.get(tableNames[<span class="hljs-number">0</span>]);
            <span class="hljs-comment">// process child tables</span>
            processChildTables(tables, table, dataNode, tableElement);
        }
    }
    <span class="hljs-keyword">return</span> tables;
}</code>

对于子表，有递归读取配置：

<code class=" hljs javascript">private <span class="hljs-keyword">void</span> processChildTables(Map<<span class="hljs-built_in">String</span>, TableConfig> tables,
            TableConfig parentTable, <span class="hljs-built_in">String</span> dataNodes, Element tableNode) {

        <span class="hljs-comment">// parse child tables</span>
        NodeList childNodeList = tableNode.getChildNodes();
        <span class="hljs-keyword">for</span> (int j = <span class="hljs-number">0</span>; j < childNodeList.getLength(); j++) {
            Node theNode = childNodeList.item(j);
            <span class="hljs-keyword">if</span> (!theNode.getNodeName().equals(<span class="hljs-string">"childTable"</span>)) {
                <span class="hljs-keyword">continue</span>;
            }
            Element childTbElement = (Element) theNode;
            <span class="hljs-comment">//读取子表信息</span>
            <span class="hljs-built_in">String</span> cdTbName = childTbElement.getAttribute(<span class="hljs-string">"name"</span>).toUpperCase();
            <span class="hljs-built_in">String</span> primaryKey = childTbElement.hasAttribute(<span class="hljs-string">"primaryKey"</span>) ? childTbElement.getAttribute(<span class="hljs-string">"primaryKey"</span>).toUpperCase() : <span class="hljs-literal">null</span>;

            boolean autoIncrement = <span class="hljs-literal">false</span>;
            <span class="hljs-keyword">if</span> (childTbElement.hasAttribute(<span class="hljs-string">"autoIncrement"</span>)) {
                autoIncrement = <span class="hljs-built_in">Boolean</span>.parseBoolean(childTbElement.getAttribute(<span class="hljs-string">"autoIncrement"</span>));
            }
            boolean needAddLimit = <span class="hljs-literal">true</span>;
            <span class="hljs-keyword">if</span> (childTbElement.hasAttribute(<span class="hljs-string">"needAddLimit"</span>)) {
                needAddLimit = <span class="hljs-built_in">Boolean</span>.parseBoolean(childTbElement.getAttribute(<span class="hljs-string">"needAddLimit"</span>));
            }
            <span class="hljs-built_in">String</span> subTables = childTbElement.getAttribute(<span class="hljs-string">"subTables"</span>);
            <span class="hljs-comment">//子表join键，和对应的parent的键，父子表通过这个关联</span>
            <span class="hljs-built_in">String</span> joinKey = childTbElement.getAttribute(<span class="hljs-string">"joinKey"</span>).toUpperCase();
            <span class="hljs-built_in">String</span> parentKey = childTbElement.getAttribute(<span class="hljs-string">"parentKey"</span>).toUpperCase();
            TableConfig table = <span class="hljs-keyword">new</span> TableConfig(cdTbName, primaryKey,
                    autoIncrement, needAddLimit,
                    TableConfig.TYPE_GLOBAL_DEFAULT, dataNodes,
                    getDbType(dataNodes), <span class="hljs-literal">null</span>, <span class="hljs-literal">false</span>, parentTable, <span class="hljs-literal">true</span>,
                    joinKey, parentKey, subTables);

            <span class="hljs-keyword">if</span> (tables.containsKey(table.getName())) {
                <span class="hljs-keyword">throw</span> <span class="hljs-keyword">new</span> ConfigException(<span class="hljs-string">"table "</span> + table.getName() + <span class="hljs-string">" duplicated!"</span>);
            }
            tables.put(table.getName(), table);
            <span class="hljs-comment">//对于子表的子表，递归处理</span>
            processChildTables(tables, table, dataNodes, childTbElement);
        }
    }</code>

对于表的dataNode对应关系，有个特殊配置即类似dataNode=”distributed(dn$1-10)”，这个含义是：

<code class="java hljs "><span class="hljs-javadoc">/**
     * distribute datanodes in multi hosts,means ,dn1 (host1),dn100
     * (host2),dn300(host3),dn2(host1),dn101(host2),dn301(host3)...etc
     *  将每个host上的datanode按照host重新排列。比如上面的例子host1拥有dn1,dn2，host2拥有dn100，dn101，host3拥有dn300，dn301,
     * 按照host重新排列： 0->dn1 (host1),1->dn100(host2),2->dn300(host3),3->dn2(host1),4->dn101(host2),5->dn301(host3)
     *
     *<span class="hljs-javadoctag"> @param</span> theDataNodes
     */</span>
    <span class="hljs-keyword">private</span> <span class="hljs-keyword">void</span> <span class="hljs-title">distributeDataNodes</span>(ArrayList<String> theDataNodes) {
        Map<String, ArrayList<String>> newDataNodeMap = <span class="hljs-keyword">new</span> HashMap<String, ArrayList<String>>(dataHosts.size());
        <span class="hljs-keyword">for</span> (String dn : theDataNodes) {
            DataNodeConfig dnConf = dataNodes.get(dn);
            String host = dnConf.getDataHost();
            ArrayList<String> hostDns = newDataNodeMap.get(host);
            hostDns = (hostDns == <span class="hljs-keyword">null</span>) ? <span class="hljs-keyword">new</span> ArrayList<String>() : hostDns;
            hostDns.add(dn);
            newDataNodeMap.put(host, hostDns);
        }

        ArrayList<String> result = <span class="hljs-keyword">new</span> ArrayList<String>(theDataNodes.size());
        <span class="hljs-keyword">boolean</span> hasData = <span class="hljs-keyword">true</span>;
        <span class="hljs-keyword">while</span> (hasData) {
            hasData = <span class="hljs-keyword">false</span>;
            <span class="hljs-keyword">for</span> (ArrayList<String> dns : newDataNodeMap.values()) {
                <span class="hljs-keyword">if</span> (!dns.isEmpty()) {
                    result.add(dns.remove(<span class="hljs-number">0</span>));
                    hasData = <span class="hljs-keyword">true</span>;
                }
            }
        }
        theDataNodes.clear();
        theDataNodes.addAll(result);
    }</code>

读取完所有表之后，记录好DB类型，这对之后的sql语句路由解析有帮助。将所有schema的配置保存在：

<code class=" hljs java"><span class="hljs-keyword">private</span> <span class="hljs-keyword">final</span> Map<String, SchemaConfig> schemas;</code>

4.3 server.xml

之后会读取载入server配置。
XMLConfigLoader.java:

<code class=" hljs avrasm">public XMLConfigLoader(SchemaLoader schemaLoader) {
    XMLServerLoader serverLoader = new XMLServerLoader()<span class="hljs-comment">;</span>
    this<span class="hljs-preprocessor">.system</span> = serverLoader<span class="hljs-preprocessor">.getSystem</span>()<span class="hljs-comment">;</span>
    this<span class="hljs-preprocessor">.users</span> = serverLoader<span class="hljs-preprocessor">.getUsers</span>()<span class="hljs-comment">;</span>
    this<span class="hljs-preprocessor">.quarantine</span> = serverLoader<span class="hljs-preprocessor">.getQuarantine</span>()<span class="hljs-comment">;</span>
    this<span class="hljs-preprocessor">.cluster</span> = serverLoader<span class="hljs-preprocessor">.getCluster</span>()<span class="hljs-comment">;</span>
    this<span class="hljs-preprocessor">.dataHosts</span> = schemaLoader<span class="hljs-preprocessor">.getDataHosts</span>()<span class="hljs-comment">;</span>
    this<span class="hljs-preprocessor">.dataNodes</span> = schemaLoader<span class="hljs-preprocessor">.getDataNodes</span>()<span class="hljs-comment">;</span>
    this<span class="hljs-preprocessor">.schemas</span> = schemaLoader<span class="hljs-preprocessor">.getSchemas</span>()<span class="hljs-comment">;</span>
    schemaLoader = null<span class="hljs-comment">;</span>
}</code>

XMLServerLoader.java

<code class=" hljs cs"><span class="hljs-keyword">public</span> <span class="hljs-title">XMLServerLoader</span>() {
    <span class="hljs-keyword">this</span>.system = <span class="hljs-keyword">new</span> SystemConfig();
    <span class="hljs-keyword">this</span>.users = <span class="hljs-keyword">new</span> HashMap<String, UserConfig>();
    <span class="hljs-keyword">this</span>.quarantine = <span class="hljs-keyword">new</span> QuarantineConfig();
    <span class="hljs-keyword">this</span>.load();
}
<span class="hljs-keyword">private</span> <span class="hljs-keyword">void</span> <span class="hljs-title">load</span>() {
    <span class="hljs-comment">//读取server.xml配置</span>
    InputStream dtd = <span class="hljs-keyword">null</span>;
    InputStream xml = <span class="hljs-keyword">null</span>;
    <span class="hljs-keyword">try</span> {
        dtd = XMLServerLoader.class.getResourceAsStream(<span class="hljs-string">"/server.dtd"</span>);
        xml = XMLServerLoader.class.getResourceAsStream(<span class="hljs-string">"/server.xml"</span>);
        Element root = ConfigUtil.getDocument(dtd, xml).getDocumentElement();
        <span class="hljs-comment">//加载System标签</span>
        loadSystem(root);
        <span class="hljs-comment">//加载User标签</span>
        loadUsers(root);
        <span class="hljs-comment">//加载集群配置</span>
        <span class="hljs-keyword">this</span>.cluster = <span class="hljs-keyword">new</span> ClusterConfig(root, system.getServerPort());
        <span class="hljs-comment">//加载权限和黑白名单</span>
        loadQuarantine(root);
    } <span class="hljs-keyword">catch</span> (ConfigException e) {
        <span class="hljs-keyword">throw</span> e;
    } <span class="hljs-keyword">catch</span> (Exception e) {
        <span class="hljs-keyword">throw</span> <span class="hljs-keyword">new</span> ConfigException(e);
    } <span class="hljs-keyword">finally</span> {
        <span class="hljs-keyword">if</span> (dtd != <span class="hljs-keyword">null</span>) {
            <span class="hljs-keyword">try</span> {
                dtd.close();
            } <span class="hljs-keyword">catch</span> (IOException e) {
            }
        }
        <span class="hljs-keyword">if</span> (xml != <span class="hljs-keyword">null</span>) {
            <span class="hljs-keyword">try</span> {
                xml.close();
            } <span class="hljs-keyword">catch</span> (IOException e) {
            }
        }
    }
}</code>

首先加载System标签