JFinal源码解析系列之三
1 数据库插件配置
public void configPlugin(Plugins me) {
C3p0Plugin cp = new C3p0Plugin("jdbc:mysql://localhost/db_name",
"userName", "password");//1.1 配置c3p0插件
me.add(cp);//1.2添加c3p0到plugins中
ActiveRecordPlugin arp = new ActiveRecordPlugin(cp);//1.3 创建ActiveRecordPlugin
me.add(arp);
arp.addMapping("user", User.class);//添加tablesName 到Model的映射
arp.addMapping("article", "article_id", Article.class);
}
}
1.1 c3p0类
public class C3p0Plugin implements IPlugin, IDataSourceProvider {
private String jdbcUrl;
private String user;
private String password;
private String driverClass = "com.mysql.jdbc.Driver";
private int maxPoolSize = 100;
private int minPoolSize = 10;
private int initialPoolSize = 10;
private int maxIdleTime = 20;
private int acquireIncrement = 2;
private ComboPooledDataSource dataSource;
public C3p0Plugin setDriverClass(String driverClass) {
if (StrKit.isBlank(driverClass))
throw new IllegalArgumentException("driverClass can not be blank.");
this.driverClass = driverClass;
return this;
}
public C3p0Plugin setMaxPoolSize(int maxPoolSize) {
if (maxPoolSize < 1)
throw new IllegalArgumentException("maxPoolSize must more than 0.");
this.maxPoolSize = maxPoolSize;
return this;
}
public C3p0Plugin setMinPoolSize(int minPoolSize) {
if (minPoolSize < 1)
throw new IllegalArgumentException("minPoolSize must more than 0.");
this.minPoolSize = minPoolSize;
return this;
}
public C3p0Plugin setInitialPoolSize(int initialPoolSize) {
if (initialPoolSize < 1)
throw new IllegalArgumentException("initialPoolSize must more than 0.");
this.initialPoolSize = initialPoolSize;
return this;
}
public C3p0Plugin setMaxIdleTime(int maxIdleTime) {
if (maxIdleTime < 1)
throw new IllegalArgumentException("maxIdleTime must more than 0.");
this.maxIdleTime = maxIdleTime;
return this;
}
public C3p0Plugin setAcquireIncrement(int acquireIncrement) {
if (acquireIncrement < 1)
throw new IllegalArgumentException("acquireIncrement must more than 0.");
this.acquireIncrement = acquireIncrement;
return this;
}
public C3p0Plugin(String jdbcUrl, String user, String password) {//1.1 调用的构造函数
this.jdbcUrl = jdbcUrl;
this.user = user;
this.password = password;
}
public C3p0Plugin(String jdbcUrl, String user, String password, String driverClass) {
this.jdbcUrl = jdbcUrl;
this.user = user;
this.password = password;
this.driverClass = driverClass != null ? driverClass : this.driverClass;
}
public C3p0Plugin(String jdbcUrl, String user, String password, String driverClass, Integer maxPoolSize, Integer minPoolSize, Integer initialPoolSize, Integer maxIdleTime, Integer acquireIncrement) {
initC3p0Properties(jdbcUrl, user, password, driverClass, maxPoolSize, minPoolSize, initialPoolSize, maxIdleTime, acquireIncrement);
}
private void initC3p0Properties(String jdbcUrl, String user, String password, String driverClass, Integer maxPoolSize, Integer minPoolSize, Integer initialPoolSize, Integer maxIdleTime, Integer acquireIncrement) {
this.jdbcUrl = jdbcUrl;
this.user = user;
this.password = password;
this.driverClass = driverClass != null ? driverClass : this.driverClass;
this.maxPoolSize = maxPoolSize != null ? maxPoolSize : this.maxPoolSize;
this.minPoolSize = minPoolSize != null ? minPoolSize : this.minPoolSize;
this.initialPoolSize = initialPoolSize != null ? initialPoolSize : this.initialPoolSize;
this.maxIdleTime = maxIdleTime != null ? maxIdleTime : this.maxIdleTime;
this.acquireIncrement = acquireIncrement != null ? acquireIncrement : this.acquireIncrement;
}
public C3p0Plugin(File propertyfile) {
FileInputStream fis = null;
try {
fis = new FileInputStream(propertyfile);
Properties ps = new Properties();
ps.load(fis);
initC3p0Properties(ps.getProperty("jdbcUrl"), ps.getProperty("user"), ps.getProperty("password"), ps.getProperty("driverClass"),
toInt(ps.getProperty("maxPoolSize")), toInt(ps.getProperty("minPoolSize")), toInt(ps.getProperty("initialPoolSize")),
toInt(ps.getProperty("maxIdleTime")),toInt(ps.getProperty("acquireIncrement")));
} catch (Exception e) {
e.printStackTrace();
}
finally {
if (fis != null)
try {fis.close();} catch (IOException e) {e.printStackTrace();}
}
}
public C3p0Plugin(Properties properties) {
Properties ps = properties;
initC3p0Properties(ps.getProperty("jdbcUrl"), ps.getProperty("user"), ps.getProperty("password"), ps.getProperty("driverClass"),
toInt(ps.getProperty("maxPoolSize")), toInt(ps.getProperty("minPoolSize")), toInt(ps.getProperty("initialPoolSize")),
toInt(ps.getProperty("maxIdleTime")),toInt(ps.getProperty("acquireIncrement")));
}
//c3p0初始化，初始化datasource
public boolean start() {
dataSource = new ComboPooledDataSource();
dataSource.setJdbcUrl(jdbcUrl);
dataSource.setUser(user);
dataSource.setPassword(password);
try {dataSource.setDriverClass(driverClass);}
catch (PropertyVetoException e) {dataSource = null; System.err.println("C3p0Plugin start error"); throw new RuntimeException(e);}
dataSource.setMaxPoolSize(maxPoolSize);
dataSource.setMinPoolSize(minPoolSize);
dataSource.setInitialPoolSize(initialPoolSize);
dataSource.setMaxIdleTime(maxIdleTime);
dataSource.setAcquireIncrement(acquireIncrement);
return true;
}
private Integer toInt(String str) {
return Integer.parseInt(str);
}
public DataSource getDataSource() {
return dataSource;
}
public boolean stop() {
if (dataSource != null)
dataSource.close();
return true;
}
}
可以看到c3p0实现了Iplugin 和IDatasoureProvider。
1.3 AtiveRecordPlugin 类中构造方法的具体实现
//其中c3p0为IDataSourceProvider的子类
public ActiveRecordPlugin(IDataSourceProvider dataSourceProvider) {
this(DbKit.MAIN_CONFIG_NAME, dataSourceProvider);
}
1.4 arp.addMapping()的具体实现
public ActiveRecordPlugin addMapping(String tableName, Class<? extends Model<?>> modelClass) {
tableList.add(new Table(tableName, modelClass));// 添加class类与name的映射
return this;
}
其中table 类保存了元数据包含列名和类型。
JFinal初始化时调用了plugins.start();
其中ActiveRecordPlugin的start方法实现如下：
public boolean start() {
if (isStarted)//isStarted是启动标识防止重复启动
return true;
if (dataSourceProvider != null)
dataSource = dataSourceProvider.getDataSource();//获取dataSource
if (dataSource == null)
throw new RuntimeException("ActiveRecord start error: ActiveRecordPlugin need DataSource or DataSourceProvider");
//生成Config设置或者使用已有的设置
if (config == null)
config = new Config(configName, dataSource, dialect, showSql, devMode, transactionLevel, containerFactory, cache);
DbKit.addConfig(config);
//建立config与数据库的关联 核心与关键
TableBuilder.build(tableList, config);
Db.init();
isStarted = true;
return true;
}
build方法实现如下：
static void build(List<Table> tableList, Config config) {
Table temp = null;
Connection conn = null;
try {
conn = config.dataSource.getConnection();//获取数据库连接
TableMapping tableMapping = TableMapping.me();//获取TableMapping 单例
//tableList中的数据为arp.add("User",User.class);
for (Table table : tableList) {
temp = table;
doBuild(table, conn, config);//建立每一个表与Model的对应关系
tableMapping.putTable(table);//将构建成功的每一个table添加到TableMapping中
DbKit.addModelToConfigMapping(table.getModelClass(), config);
}
} catch (Exception e) {
if (temp != null)
System.err.println("Can not create Table object, maybe the table " + temp.getName() + " is not exists.");
throw new ActiveRecordException(e);
}
finally {
config.close(conn);
}
}
doBuild()的实现方法如下：
private static void doBuild(Table table, Connection conn, Config config) throws SQLException {
table.setColumnTypeMap(config.containerFactory.getAttrsMap());
if (table.getPrimaryKey() == null)//table的主键是否为空
table.setPrimaryKey(config.dialect.getDefaultPrimaryKey());//将id设置为table的主键
String sql = config.dialect.forTableBuilderDoBuild(table.getName());//"select * from "+tablename+" where 1=2"
Statement stm = conn.createStatement();
ResultSet rs = stm.executeQuery(sql);
ResultSetMetaData rsmd = rs.getMetaData();//获取metadata
for (int i=1; i<=rsmd.getColumnCount(); i++) {
String colName = rsmd.getColumnName(i);//获取列名
String colClassName = rsmd.getColumnClassName(i);//获取the fully-qualified name
Class<?> clazz = strToType.get(colClassName);
if (clazz != null) {//判断是否为class类
table.setColumnType(colName, clazz);
}
else {
int type = rsmd.getColumnType(i);//获取字段类型
if (type == Types.BLOB) {//blob
table.setColumnType(colName, byte[].class);
}
else if (type == Types.CLOB || type == Types.NCLOB) {//Clob||NCLOB类型
table.setColumnType(colName, String.class);
}
else {
table.setColumnType(colName, String.class);
}
// core.TypeConverter
// throw new RuntimeException("You've got new type to mapping. Please add code in " + TableBuilder.class.getName() + ". The ColumnClassName can't be mapped: " + colClassName);
}
}
rs.close();
stm.close();
}
巧妙地利用“select * from tablename where 1=2"的语句获取table的相关信息，实现数据库到model的精巧映射。