sharding-jdbc中WrapperAdapter的作用是什么

本篇文章为大家展示了sharding-jdbc中WrapperAdapter的作用是什么，内容简明扼要并且容易理解，绝对能使你眼前一亮，通过这篇文章的详细介绍希望你能有所收获。

Wrapper

jdk-12.jdk/Contents/Home/lib/src.zip!/java.sql/java/sql/Wrapper.java

public interface Wrapper {     T unwrap(java.lang.Class iface) throws java.sql.SQLException;    boolean isWrapperFor(java.lang.Class iface) throws java.sql.SQLException;}

• Wrapper接口定义了unwrap、isWrapperFor方法

WrapperAdapter

incubator-shardingsphere-4.0.0-RC1/sharding-jdbc/sharding-jdbc-core/src/main/java/org/apache/shardingsphere/shardingjdbc/jdbc/adapter/WrapperAdapter.java

public abstract class WrapperAdapter implements Wrapper {        private final Collection jdbcMethodInvocations = new ArrayList<>();        @SuppressWarnings("unchecked")    @Override    public final  T unwrap(final Class iface) throws SQLException {        if (isWrapperFor(iface)) {            return (T) this;        }        throw new SQLException(String.format("[%s] cannot be unwrapped as [%s]", getClass().getName(), iface.getName()));    }        @Override    public final boolean isWrapperFor(final Class iface) {        return iface.isInstance(this);    }        /**     * record method invocation.     *      * @param targetClass target class     * @param methodName method name     * @param argumentTypes argument types     * @param arguments arguments     */    @SneakyThrows    public final void recordMethodInvocation(final Class targetClass, final String methodName, final Class[] argumentTypes, final Object[] arguments) {        jdbcMethodInvocations.add(new JdbcMethodInvocation(targetClass.getMethod(methodName, argumentTypes), arguments));    }        /**     * Replay methods invocation.     *      * @param target target object     */    public final void replayMethodsInvocation(final Object target) {        for (JdbcMethodInvocation each : jdbcMethodInvocations) {            each.invoke(target);        }    }}

• WrapperAdapter声明实现java.sql.Wrapper接口，它定义了JdbcMethodInvocation集合；recordMethodInvocation方法会往jdbcMethodInvocations添加JdbcMethodInvocation；replayMethodsInvocation方法则会挨个执行JdbcMethodInvocation的invoke方法

JdbcMethodInvocation

incubator-shardingsphere-4.0.0-RC1/sharding-jdbc/sharding-jdbc-core/src/main/java/org/apache/shardingsphere/shardingjdbc/jdbc/adapter/invocation/JdbcMethodInvocation.java

@RequiredArgsConstructorpublic class JdbcMethodInvocation {        @Getter    private final Method method;        @Getter    private final Object[] arguments;        /**     * Invoke JDBC method.     *      * @param target target object     */    @SneakyThrows    public void invoke(final Object target) {        method.invoke(target, arguments);    }}

• JdbcMethodInvocation的invoke方法执行的是method.invoke

小结

WrapperAdapter声明实现java.sql.Wrapper接口，它定义了JdbcMethodInvocation集合；recordMethodInvocation方法会往jdbcMethodInvocations添加JdbcMethodInvocation；replayMethodsInvocation方法则会挨个执行JdbcMethodInvocation的invoke方法

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