MyBatis Interceptor: Replace Text in SQL Before Execution

To replace text in SQL before execution in MyBatis using an interceptor, you can create a custom interceptor that implements the 'Interceptor' interface and overrides the 'intercept' method.

Here's an example implementation:

public class ReplaceSqlInterceptor implements Interceptor {

  @Override
  public Object intercept(Invocation invocation) throws Throwable {
    MappedStatement mappedStatement = (MappedStatement) invocation.getArgs()[0];
    Object parameter = invocation.getArgs()[1];
    BoundSql boundSql = mappedStatement.getBoundSql(parameter);
    String sql = boundSql.getSql();
    
    // Replace text in SQL
    sql = sql.replace('old_text', 'new_text');
    
    // Update the BoundSql with the modified SQL
    BoundSql newBoundSql = new BoundSql(mappedStatement.getConfiguration(), sql,
      boundSql.getParameterMappings(), boundSql.getParameterObject());
    MappedStatement newMappedStatement = copyFromMappedStatement(mappedStatement, new BoundSqlSqlSource(newBoundSql));
    invocation.getArgs()[0] = newMappedStatement;
    
    // Proceed with the original query execution
    return invocation.proceed();
  }

  @Override
  public Object plugin(Object target) {
    return Plugin.wrap(target, this);
  }

  @Override
  public void setProperties(Properties properties) {
    // No properties to set
  }

  private static MappedStatement copyFromMappedStatement(MappedStatement ms, SqlSource newSqlSource) {
    MappedStatement.Builder builder = new MappedStatement.Builder(ms.getConfiguration(), ms.getId(),
      newSqlSource, ms.getSqlCommandType());
    builder.resource(ms.getResource());
    builder.fetchSize(ms.getFetchSize());
    builder.statementType(ms.getStatementType());
    builder.keyGenerator(ms.getKeyGenerator());
    builder.keyProperty(ms.getKeyProperty());
    builder.timeout(ms.getTimeout());
    builder.parameterMap(ms.getParameterMap());
    builder.resultMaps(ms.getResultMaps());
    builder.cache(ms.getCache());
    builder.useCache(ms.isUseCache());
    return builder.build();
  }

  private static class BoundSqlSqlSource implements SqlSource {
    private final BoundSql boundSql;

    public BoundSqlSqlSource(BoundSql boundSql) {
      this.boundSql = boundSql;
    }

    @Override
    public BoundSql getBoundSql(Object parameterObject) {
      return boundSql;
    }
  }
}

In this example, the 'intercept' method first retrieves the SQL statement from the 'MappedStatement' and 'BoundSql' objects. It then replaces any occurrences of the old text with the new text using the 'replace' method.

Next, it creates a new 'BoundSql' object with the modified SQL, and uses it to create a new 'MappedStatement' object with the 'copyFromMappedStatement' method. This new 'MappedStatement' is used to update the first element of the 'args' array, which contains the original 'MappedStatement'.

Finally, the method proceeds with the original query execution by calling 'invocation.proceed()'.

To use this interceptor in MyBatis, you need to add it to the 'Configuration' object:

Configuration config = new Configuration();
config.addInterceptor(new ReplaceSqlInterceptor());

This will apply the interceptor to all SQL statements executed by MyBatis.